The phylogenetics of Teleosauroidea (Crocodylomorpha, Thalattosuchia) and implications for their ecology and evolution

Introduction

Teleosauroid crocodylomorphs—distant extinct relatives of extant crocodylians (which include alligators, crocodiles, caimans and gavials)—were a near-globally distributed clade that frequented freshwater, brackish, lagoonal and deep-water marine ecosystems throughout the Jurassic (Buffetaut, 1982; Hua & Buffetaut, 1997; Hua, 1999; Young et al., 2014; Foffa, Young & Brusatte, 2015; Foffa et al., 2019; Johnson et al., 2015; Martin et al., 2016; Johnson et al., 2017, 2018; Johnson, Young & Brusatte, 2019). They have frequently been regarded as marine analogues of extant gavials, as the majority of species had an elongate and tubular snout, high tooth count and dorsally directed orbits, suggestive of a feeding style of catching small, fast-moving prey (Andrews, 1909, 1913; Buffetaut, 1982; Hua, 1999). Teleosauroids are part of the wider crocodylomorph clade Thalattosuchia, which also includes the metriorhynchoids: the only archosaurs to adopt a fully pelagic, open-ocean, swimming lifestyle in the manner of modern cetaceans (Young et al., 2010; Parrilla-Bel et al., 2013; Foffa & Young, 2014).

While teleosauroid skeletal and dental morphology has been well documented from the 18th Century to present (Chapman, 1758; Cuvier, 1824; Von Meyer, 1837; Eudes-Deslongchamps, 1867; Blake, 1876; Andrews, 1909, 1913; Westphal, 1961, 1962; Young et al., 2014; Johnson et al., 2017; Johnson, Young & Brusatte, 2019; Foffa et al., 2019; Sachs et al., 2019a), the evolutionary relationships of these crocodylomorphs are poorly understood and little studied. This is problematic, as phylogenies are crucial when evaluating evolutionary changes throughout time (Purvis, Gittleman & Brooks, 2005; Mishra & Thines, 2014). One of the major problems in teleosauroid systematics is the nomenclatural nightmare that is the taxon Steneosaurus. Widespread taxonomic lumping has seen this genus become a ‘wastebasket’ for a multitude of species. The validity of Steneosaurus has recently been called into question (Jouve et al., 2017; Johnson, Young & Brusatte, 2020) as the type specimen of the type species, Steneosaurus rostromajor Geoffroy Saint-Hilaire, 1825 (MNHN.RJN 134c-d), has rarely been referenced or figured in the literature since its preliminary descriptions by Cuvier (1800, 1808, 1812, 1824) and Geoffroy Saint-Hilaire (1825, 1831). Another problematic issue reinforced during the 20th Century (Andrews, 1909, 1913) is the contention that while there are noticeable differences between the skulls of teleosauroid species, the postcranial skeleton only shows superficial differences. This led to the assumption that teleosauroids must have lived in similar habitats with a conservative body plan (Andrews, 1913; Buffetaut, 1982). However, recent studies (Young et al., 2014; Johnson et al., 2017; Foffa et al., 2019; Martin et al., 2016, 2019; Wilberg, Turner & Brochu, 2019) have begun to dispute this notion, showing, in terms of postcranial anatomy and palaeoenvironment, that teleosauroids were more diverse than originally thought.

Herein we present an in-depth, comprehensive phylogenetic study of Teleosauroidea, using the most recently updated crocodylomorph dataset. We will: (1) explore the historical background of teleosauroid phylogenetics; (2) discuss the materials and phylogenetic methods used; (3) provide a novel, comprehensive taxonomic layout of Teleosauroidea; (4) list detailed descriptions of both newly scored and morphologically important characters; (5) evaluate the results of the phylogenetic analyses; and (6) elucidate what this new phylogeny implies about teleosauroid ecomorphological and distributional patterns.

Historical Background

Previous teleosauroid phylogenetics—late 1900s, early 2000s and Mueller-Töwe’s (2006) contributions

Although descriptions of teleosauroid fossils were prevalent during the mid-18th and 19th Centuries (Chapman, 1758; Morton & Wooller, 1758; Cuvier, 1808, 1812, 1824; Geoffroy Saint-Hilaire, 1825, 1831; Von Meyer, 1837; Eudes-Deslongchamps, 1867; Westphal, 1961), investigation into their evolutionary relationships remains a relatively new area of study. While Buffetaut (1980a, 1980b) and Vignaud (1995) briefly took note on the general interrelationships within Thalattosuchia, Benton & Clark (1988) examined the overall phylogenetic affinities of crocodylomorphs as a group. During the early 21st Century, thalattosuchians continued to be incorporated into larger crocodylomorph studies. However, these analyses were not focused on the interrelationships between thalattosuchians, and usually included only one or two teleosauroid taxa, namely Steneosaurus bollensis Jäger, 1828 and Pelagosaurus typus Bronn, 1841, which was considered a basal teleosauroid during that time (Gasparini, Pol & Spalletti, 2006; Pol & Gasparini, 2009).

Mueller-Töwe’s (2006) unpublished thesis included the first analysis that focused specifically on thalattosuchian phylogenetics, in particular Teleosauridae, and was built upon a preliminary study (Mueller-Töwe, 2005). Mueller-Töwe’s (2006) dataset included 189 characters, with twelve teleosauroids out of 29 taxa: Machimosaurus hugii Von Meyer, 1837; Platysuchus multiscrobiculatus (Berckhemer, 1929) Westphal (1961); Steneosaurus baroni Newton, 1893; S. bollensis; Steneosaurus edwardsi Eudes-Deslongchamps, 1868a; Steneosaurus boutilieri Eudes-Deslongchamps, 1868b; Steneosaurus brevior Blake, 1876; Steneosaurus gracilirostris Westphal, 1961; Steneosaurus leedsi Andrews, 1909 (which also incorporated Mycterosuchus nasutus Andrews, 1913); Steneosaurus megarhinus Hulke, 1871; Steneosaurus obtusidens Andrews, 1909; Steneosaurus (Aeolodon) priscus Von Sömmerring, 1814; and Teleosaurus cadomensis (Lamouroux, 1820). Other taxa were considered insufficient to include in the dataset (e.g. specimens that the author felt contained insufficient information and/or skeletal material), and only four teleosauroids used in the analysis were studied in-depth: Pl. multiscrobiculatus, S. brevior, S. bollensis and S. gracilirostris (note that Mueller-Töwe (2006) focused specifically on Toarcian species). In addition, there were no ordered or weighted characters, and multi-state characters were treated as polymorphs (Mueller-Töwe, 2006). Disregarding ordered or weighted characters, however, presents a problem, as ordered parsimony is less artefactual and susceptible to polarization errors, and displays an overall higher performance level (Mueller-Töwe, 2006) than unordered parsimony (Grand et al., 2013; Rineau et al., 2015).

Mueller-Töwe’s (2006) strict consensus topology (Fig. 1A) produced 123 most parsimonious trees (MPTs) with a tree length of 423, an ensemble consistency index (CI) of 0.6312 and an ensemble retention index (RI) of 0.6549. The teleosauroids were found to be monophyletic and included: (1) Pel. typus as the basal-most teleosauroid; (2) a paraphyletic Steneosaurus; and (3) Platysuchus as the most closely related taxon to Machimosaurus (Fig. 1A). However, it is important to note that in Mueller-Töwe (2006) there are several factual errors and inconsistencies, particularly in the anatomical descriptions, which may have had an influence on the phylogenetic results. Note that as her final analyses were not subject to peer-review publication, it is unfair to give undue criticism.

When re-describing T. cadomensis, Jouve (2009) performed a phylogenetic analysis consisting of 75 taxa and 343 characters, and included the teleosauroids Teleosaurus cadomensis, Peipehsuchus teleorhinus Young, 1948 (now known as the Chinese teleosauroid IVPP V 10098), S. bollensis, Pel. typus (still considered to be a teleosauroid by some, although there was growing support for it as a metriorhynchoid: for example Buffetaut, 1980a; Mercier, 1933), Steneosaurus larteti Eudes-Deslongchamps, 1866 and ‘Mystriosaurus’ Kaup, 1834 (= Pelagosaurus tomarensis, MUHNAC unnumbered specimen: Telles-Antunes, 1967). The strict consensus (Fig. 1B) was found from four MPTs. Another study (Pierce, Angielczyk & Rayfield, 2009) conducted a parsimony analysis based off Mueller-Töwe’s (2006) unpublished character matrix; however, species they considered synonymous (e.g. S. leedsi and S. megarhinus) were combined and taxa not used in the authors’ landmark-based geometric morphometric analysis were deleted. Therefore, only seven teleosauroids were included (Steneosaurus heberti Morel de Glasville, 1876, S. gracilirostris, Pl. multiscrobiculatus, Mac. hugii, S. leedsi, S. bollensis and S. brevior), as well as Pel. typus, and Metriorhynchus superciliosus De Blainville, 1853 as the outgroup (Pierce, Angielczyk & Rayfield, 2009). This dataset produced two MPTs with 115 steps (CI = 0.621).

Methods

Systematic Palaeontology—genus and Species Level Taxonomy

As mentioned previously, the most historically important and commonly utilized teleosauroid genus Steneosaurus has been recognized as a ‘wastebasket’ taxon by researchers and has continuously been recovered as paraphyletic or polyphyletic in phylogenetic analyses (Mueller-Töwe, 2006; Wilberg, 2015b; Foffa et al., 2019; Johnson, Young & Brusatte, 2019). In addition, no type species had until recently been officially designated for Steneosaurus under International Commission on Zoological Nomenclature (ICZN) Code rules. Johnson, Young & Brusatte (2020) set out to rectify this problem by evaluating the validity of Steneosaurus. The authors designated Steneosaurus rostromajor Geoffroy Saint-Hilaire, 1825, as the type species of Steneosaurus, designated MNHN.RJN 134c-d as the lectotype, provided a thorough literature and descriptive review of the specimen, and compared it with other relevant teleosauroid taxa. Their final verdict considered S. rostromajor (MNHN.RJN 134c-d) to be a nomen dubium, and proposed that the genus Steneosaurus is undiagnostic, due to (1) lack of autapomorphic characters (2) poor preservation (3) a generic concept that has changed multiple times through time; and (4) uncertainty of teleosauroid ontogenetic variation and sexual dimorphism (Johnson, Young & Brusatte, 2020).

Johnson, Young & Brusatte (2020) suggested that establishing a ‘clean’ foundation of teleosauroid taxonomy using diagnostic type species/specimens, with every nomenclatural act correctly formulated, was the next course of action. Therefore, we believe that it is necessary to erect new proposed teleosauroid genera first, as a direct result of the proposal of Steneosaurus as a nomen dubium.

This article in Portable Document Format (PDF) signifies a published work in accordance with the ICZN. As such, the new genus and species names contained will be effectively published under ICZN Code from the electronic edition. This work and the nomenclatural acts contained within it have been registered in ZooBank, the online registration system for the ICZN. The following ZooBank LSIDs (Life Science Identifiers) and associated information may be viewed through a standard web browser by adding the LSID to the prefix http://zoobank.org/. The LSID for this publication is: urn:lsid:zoobank.org:pub:7CC3CA17-F08F-48AD-9F16-8537B6BAAC1F.

CROCODYLOMORPHA Hay, 1930 (sensu Nesbitt, 2011)

THALATTOSUCHIA Fraas, 1901 (sensu Young & Andrade, 2009)

TELEOSAUROIDEA Geoffroy Saint-Hilaire, 1831 (sensu herein, see below)

Plagiophthalmosuchus gen. nov.

Type species—Steneosaurus gracilirostris Westphal, 1961. Now referred to as Plagiophthalmosuchus gracilirostris (Westphal, 1961), comb. nov. urn:lsid:zoobank.org:act:1AC91E3C-FC9A-470B-B9A9-3220B9823C0F

Etymology—‘Lateral-eyed crocodile.’ Plágios (πλάγιος) and ofthalmós (οφθαλμός) are Greek for ‘lateral’ and ‘eye’, respectively (referring to the laterally directed orbits of this taxon); suchus is the Latinized form of the Greek soukhos (σοῦχος), meaning crocodile.

Diagnosis—same as the only known species (monotypic genus).

Plagiophthalmosuchus gracilirostris (Westphal, 1961) comb. nov.

(Fig. 2)

Holotype—NHMUK PV OR 14792, a nearly complete skeleton.

Paratype—NHMUK PV OR 15500, a complete skull and mandible.

Referred material—DONMG specimen (nearly complete skull and mandible); MNHNL TU515 (nearly complete skull and mandible); YORM 2012.38 (nearly complete skull).

Age—early Toarcian, Early Jurassic.

Localities—Whitby, Yorkshire, UK; Dudelange-Bettembourg, southern Luxembourg.

Stratigraphic horizons—Alum Shale Member, Whitby Mudstone Formation, Lias Group; Harpoceras serpentinum ammonite Zone (‘schistes bitumineux’).

Scoring Sources—the holotype (NHMUK PV OR 14792), paratype and all referred specimens were studied first-hand. Photographs of DONMG were provided by D. Lomax.

Autapomorphic characters of Pla. gracilirostris—in the antorbital fenestra, the external fenestra is significantly larger than internal fenestra (over 25%); antorbital fenestra is moderately large, being at least half the diameter of the orbit; internal fenestra is approximately 50% of the length of the orbit; supratemporal fossa is slightly larger (~25%) than the length of the orbit; basioccipital sub-vertical and somewhat visible in occipital view; exoccipital-opisthotics are dorsoventrally slender and paraoccipital processes have a straight distal margin; orbit positioned laterally with a slight dorsal inclination; dorsal border at dentary-surangular is relatively straight; glenoid fossa of the articular oriented subtly anterodorsally.

Emended diagnosis—longirostrine snout; tooth row and quadrate condyle aligned, both at a lower level than the occipital condyle (shared with Macrospondylus); ornamentation absent on prefrontal (shared with I. potamosiamensis, Aeolodon, Bathysuchus and Sericodon) and lacrimal (shared with I. potamosiamensis, Sericodon, Aeolodon and Macrospondylus); greater than 67% of the total premaxilla length is posterior to the external nares (similar to the Chinese teleosauroid, I. potamosiamensis, Mycterosuchus, Aeolodon, Bathysuchus and Sericodon); external nares oriented anterodorsally (shared with Indosinosuchus, the Chinese teleosauroid, Teleosaurus, Platysuchus, Mycterosuchus, Aeolodon, Bathysuchus and Sericodon); premaxilla anterior and anterolateral margins are not sub-vertical (shared with Macrospondylus, Andrianavoay, Charitomenosuchus, Deslongchampsina, Proexochokefalos, Neosteneosaurus and Machimosaurini); antorbital fenestra is anteroposteriorly elongated (similar to Deslongchampsina); frontal broader than orbital width (shared with Mystriosaurus, Platysuchus, Teleosaurus, Mycterosuchus, Bathysuchus, Aeolodon, Pr. cf. bouchardi, Neosteneosaurus, Mac. buffetauti and Mac. mosae); squamosal projects further posteriorly than the occipital condyle (shared with the Chinese teleosauroid, Neosteneosaurus, Yvridiosuchus, Lemmysuchus and Mac. mosae); orbit longitudinal ellipsoid in shape; basioccipital tubera reduced (shared with Mycterosuchus, Bathysuchus and Sericodon); supraoccipital dorsoventrally tall (shared with Clovesuurdameredeor, Andrianavoay and Lemmysuchus); angular straight and mainly horizontal, especially the anterior part (shared with Mystriosaurus); ventral margin of mandible is poorly curved (shared with Mystriosaurus); proximal humerus expanded and hooked (similar to Platysuchus and Teleosaurus); tibia evidently shorter than the femur (shared with Platysuchus).

Mystriosaurus Kaup, 1834

Type species—Mystriosaurus laurillardi Kaup, 1834.

Etymology—‘Spoon lizard’. Mystrio refers to the spoon-shaped anterior rostrum in dorsal view, and saurus is the Latinized version of saûros (σαυρoς), which is Ancient Greek for lizard.

Diagnosis—same as the only known species (monotypic genus).

Mystriosaurus laurillardi Kaup, 1834

(Fig. 3)

Holotype—HLMD V946-948, a partial skull.

Referred material—NHMUK PV OR 14781 (nearly complete skull and mandible), holotype of Steneosaurus brevior.

Age—Harpoceras serpentinum Sub-Boreal ammonite Zone, early Toarcian, Early Jurassic.

Localities—Altdorf, Germany; Whitby, Yorkshire, UK.

Stratigraphic horizons—Posidonia Shale Formation; Mulgrave Shale Member, Whitby Mudstone Formation, Lias Group.

Scoring sources—NHMUK PV OR 14781 was studied first-hand. The holotype (HLMD V946-948) was examined using high quality photographs provided by S. Sachs, and also discussed at great length with S. Sachs.

Autapomorphic characters of Mys. laurillardi—well-developed and extensive ornamentation on the nasals; external nares oriented anteriorly; antorbital fenestra is sub-rectangular in shape; supratemporal fossae form an approximate isosceles trapezoid-shape; medial margin of supratemporal arch relatively straight in dorsal view, with no significant concavity; prominent anterior notch in the dentaries; mandibular fenestra poorly elliptic; large robust teeth with numerous, conspicuous apicobasally aligned enamel ridges and a pointed apex, with more anteriorly-placed tooth crowns being procumbent.

Emended diagnosis—mesorostrine skull; well-developed and extensive ornamentation on the premaxillae, maxillae, frontal, prefrontal, lacrimal and postorbital; frontal ornamentation composed of small sub-circular to elongate pits that are closely spaced or, that can fuse and become a ridge-groove pattern (similar to Mycterosuchus); slight constriction of the snout anterior to the orbits (similar to Deslongchampsina); large and numerous neurovascular foramina on the premaxillae, maxillae and dentaries (shared with Machimosaurini); external nares 8-shaped in dorsal view (shared with the Chinese teleosauroid, I. potamosiamensis, Bathysuchus and Aeolodon); dorsoventrally deep premaxilla (similar to I. kalasinensis); anteroposterior premaxilla length less than 25% of total rostral length (shared with the Chinese teleosauroid, Mac. buffetauti and Mac. mosae); premaxilla anterior and anterolateral margins are orientated anteroventrally and extend ventrally in lateral view (shared with the Chinese teleosauroid, Indosinosuchus, Platysuchus, Mycterosuchus, Aeolodon, Bathysuchus and Sericodon); antorbital fenestrae almost equidistant to orbit and alveolar margin (shared with Platysuchus); antorbital fenestra is large relative to orbits, where the anteroposterior length is approximately 25% orbital anteroposterior length (similar to Plagiophthalmosuchus and Deslongchampsina); anterolateral margin of supratemporal fossae noticeably inclined anterolaterally (shared with the Chinese teleosauroid, Indosinosuchus, Platysuchus, Teleosaurus, Mycterosuchus, Aeolodon, Bathysuchus and Sericodon); the anterior region of the supratemporal fenestra has well-rounded lateral and medial margins; frontal width broader than orbital width (shared with Plagiophthalmosuchus, Platysuchus, Teleosaurus, Mycterosuchus, Aeolodon, Bathysuchus, Sericodon, Pr. cf. bouchardi, Neosteneosaurus, Mac. buffetauti and Mac. mosae); short frontal anteromedial process, (similar to Clovesuurdameredeor); orbits subcircular in shape and dorsolaterally orientated; postorbital reaches orbit posteroventral margin (shared with the Chinese teleosauroid, I. potamosiamensis, Platysuchus, Teleosaurus and Mycterosuchus); mandibular symphysis slightly less than half the mandibular length, between 45 and 50% (similar to I. potamosiamensis, Deslongchampsina and Proexochokefalos); deep, well-developed reception pits throughout the anterior- to mid-maxilla and gradually disappear (similar to Charitomenosuchus, Deslongchampsina and Proexochokefalos); ventral border of angular horizontal and poorly curved, especially the anterior part (similar to Plagiophthalmosuchus); four teeth per premaxilla; maxillary alveolar count at least 29 (modified from Young & Steel, in press) (similar to the Chinese teleosauroid, I. potamosiamensis, Neosteneosaurus, Yvridiosuchus and Mac. buffetauti); dentary alveolar count approximately 30 to 33 alveolar pairs; P1 and P2 both oriented anteriorly (shared with I. potamosiamensis, Platysuchus, Macrospondylus, Deslongchampsina, Neosteneosaurus, Yvridiosuchus and Lemmysuchus).

Clovesuurdameredeor gen. nov.

Type species—Steneosaurus stephani Hulke, 1877. Now referred to as Clovesuurdameredeor stephani (Hulke, 1877), comb. nov. urn:lsid:zoobank.org:act:B9FC0E91-9153-4F6B-B4B7-817839A9E7DD

Etymology—‘Clovesuurda’s sea creature’. Clovesuurda was the Medieval Latin name of the village of Closworth (written in the Doomsday Book of 1086), the locality where the holotype was found; meredēor is Old English for ‘sea creature’.

Diagnosis—same as the only known species (monotypic genus).

Clovesuurdameredeor stephani (Hulke, 1877) comb. nov.

(Fig. 4)

Holotype—NHMUK PV OR 49126, a partial skull and anterior section of mandible.

Age—Bathonian, Middle Jurassic.

Locality—Closworth, Dorsetshire, UK.

Stratigraphic horizon—Great Oolite Group, Cornbrash Formation.

Scoring sources—the holotype (NHMUK PV OR 49126) was examined first-hand.

Autapomorphic characters of Cl. stephani—prefrontal is anteroposteriorly short and mediolaterally broadened; posterior projections of the nasals not elongated and level with prefrontal-orbit contact in dorsal view; anteromedial process of the frontal is posterior to the prefrontals; anteromedial process of the frontal is anteroposteriorly short and mediolaterally broad; jugal extends anteriorly to the prefrontal.

Emended diagnosis—frontal ornamentation extends from the centre to the lateral- and anterior-most areas (shared with Plagiophthalmosuchus, the Chinese teleosauroid, Indosinosuchus, Platysuchus, Teleosaurus, Mycterosuchus and Macrospondylus); presence of small antorbital fenestrae; no anterolateral expansion or inclination of the supratemporal fenestrae (shared with Plagiophthalmosuchus, Macrospondylus, Charitomenosuchus, Seldsienean, Deslongchampsina, Proexochokefalos, Neosteneosaurus and Machimosaurini); frontal subequal to orbital width (shared with the Chinese teleosauroid, I. kalasinensis, Macrospondylus, Charitomenosuchus, Deslongchampsina, Proexochokefalos, Yvridiosuchus, Mac. hugii and Mac. rex); circular orbits (shared with Mystriosaurus, Indosinosuchus, Teleosaurus, Mycterosuchus, Sericodon, Lemmysuchus and Machimosaurus); anterior process of the jugal is slender and elongated (shared with Charitomenosuchus, Proexochokefalos, Neosteneosaurus and Machimosaurini).

The Chinese teleosauroid previously referred to Peipehsuchus teleorhinus Young, 1948 (Li, 1993).

(Fig. 5)

Specimen—IVPP V 10098, a complete skull.

Age—Toarcian, Early Jurassic.

Locality—Daxian, Szechuan, China.

Stratigraphic horizon—Ziliujing Formation.

Scoring sources—IVPP V 10098 was examined first-hand and was also discussed in great length with E. Wilberg.

Autapomorphic characters of IVPP V 10098—extreme constriction of premaxillae posterior to external nares (relative to other teleosauroids), creating a laterally expanded, ‘beak-like’ premaxilla; anterior- to mid-maxilla undulates mediolaterally in dorsal view; well-developed palatal canals; the first premaxillary alveolus (P1) and second premaxillary alveolus (P2) oriented immediately laterally to one another, with the anterior-most margins of both alveoli sloping weakly anterolaterally; weak lateral expansion of the premaxilla (the P3 is situated marginally ventrally to the P2); P3 is enlarged relative to the P2 and approximately the same size as the P4.

Emended diagnosis—mesorostrine skull; tooth row and occipital condyle aligned, and quadrate condyle at a lower level (shared with Charitomenosuchus, Proexochokefalos, Neosteneosaurus and Machimosaurini); tooth row and occipital condyle aligned on the same plane with quadrate at a slightly lower level (similar to Charitomenosuchus, Proexochokefalos, Neosteneosaurus and Machimosaurini); shallow ornamentation of the premaxillae and maxillae (similar to Indosinosuchus, Aeolodon, Bathysuchus and Sericodon); frontal ornamentation extends from the centre to the lateral- and anterior-most areas (shared with Plagiophthalmosuchus, Indosinosuchus, Platysuchus, Teleosaurus, Mycterosuchus, Macrospondylus and Clovesuurdameredeor); external nares oriented anterodorsally (shared with Plagiophthalmosuchus, Indosinosuchus, Platysuchus, Teleosaurus, Mycterosuchus, Aeolodon, Bathysuchus and Sericodon); external nares ‘8-shaped’ in anterior view (shared with Mystriosaurus, I. potamosiamensis, Bathysuchus and Aeolodon); premaxilla anteroposterior length less than 25% of total rostrum length (shared with Mystriosaurus, Mac. buffetauti and Mac. mosae); premaxilla anterior and anterolateral margins are orientated anteroventrally and extend ventrally (shared with Indosinosuchus, Platysuchus, Mycterosuchus, Aeolodon, Bathysuchus and Sericodon); over 67% of total premaxilla length posterior to the external nares (shared with Plagiophthalmosuchus, I. potamosiamensis, Mycterosuchus, Aeolodon, Bathysuchus and Sericodon); small antorbital fenestrae present; supratemporal fenestrae sub-rectangular in shape; anterolateral margin of supratemporal fossae noticeably inclined anterolaterally (shared with Mystriosaurus, Indosinosuchus, Teleosaurus, Platysuchus, Mycterosuchus, Aeolodon, Bathysuchus and Sericodon); frontal width subequal with orbital width (shared with I. kalasinensis, Macrospondylus, Clovesuurdameredeor, Charitomenosuchus, Proexochokefalos, Yvridiosuchus, Mac. hugii and Mac. rex); squamosal project further posteriorly than occipital condyle (shared with Plagiophthalmosuchus, Neosteneosaurus, Yvridiosuchus, Lemmysuchus and Mac. mosae); orbit anteroposteriorly elongated and ellipsoid in shape (similar to Plagiophthalmosuchus, Platysuchus, Aeolodon, Macrospondylus, Charitomenosuchus, Seldsienean, Deslongchampsina, Proexochokefalos and Neosteneosaurus); postorbital reaches the orbit posteroventral margin (shared with Mystriosaurus, I. potamosiamensis, Platysuchus, Teleosaurus and Mycterosuchus); pterygoid flange oriented horizontally (shared with Teleosaurus); four premaxillary alveolar pairs; 27 maxillary alveolar pairs; P3 and P4 do not form a couple (shared with Bathysuchus); small P1 compared to the P2 (similar to Macrospondylus).

Remarks—this taxon, along with the holotype of Peipehsuchus teleorhinus (IVPP RV 48001), is currently being re-described by MM Johnson and colleagues.

Platysuchus Westphal, 1961

Type species—Mystriosaurus multiscrobiculatus Berckhemer, 1929. Now referred to as Platysuchus multiscrobiculatus (Berckhemer, 1929), Westphal, 1961.

Etymology—‘Wide crocodile’. Platys comes from the Greek platýs (πλατύς) meaning wide (referring to the flattened, expanded osteoderms and dermal shield), and suchus is the Latinized form of the Greek soukhos (σοῦχος), meaning crocodile.

Diagnosis—same as the only known species (monotypic genus).

Platysuchus multiscrobiculatus (Berckhemer, 1929) Westphal, 1961

(Fig. 6)

Holotype—SMNS 9930, a nearly complete skeleton.

Referred material—MNHNL TU895 (a partial rostrum); UH 1 (complete skeleton).

Age—lower Toarcian, Early Jurassic.

Localities—Holzmaden, Baden-Württemberg, Germany; Foetz, Luxembourg.

Stratigraphic horizons—Posidonia Shale Formation; Harpoceras serpentinum ammonite Zone (‘schistes bitumineux’).

Scoring sources—the holotype (SMNS 9930) and MNHNL TU895 were examined first-hand. Additional information was taken from Westphal (1961, 1962).

Autapomorphic characters of Pl. multiscrobiculatus—prefrontal and lacrimal both ornamented with meandering, elongated grooves; mid- and posterior squamosal well ornamented with small, circular, closely packed pits; frontal contribution to the intertemporal bar frontal wider than the parietal in dorsal view; jugal excluded from the orbit by lacrimal-postorbital contact; P1 and P2 do not form a couplet and are not oriented on the anterior margin of the premaxilla; tuberculum of the dorsal rib medium-sized; ischium with thickened, robust ischial neck; shortened, stocky pubis with a relatively subcircular proximal rim.

Emended diagnosis—longirostrine snout; tooth row and quadrate condyle unaligned with the tooth row at a lower level, and both below the occipital condyle (shared with Teleosaurus); tooth row at a lower level than the quadrate (shared with Plagiophthalmosuchus, Indosinosuchus, Teleosaurus, Mycterosuchus and Macrospondylus); frontal ornamentation extends from the centre to lateral- and anterior-most regions (shared with Plagiophthalmosuchus, the Chinese teleosauroid, Indosinosuchus, Teleosaurus, Mycterosuchus, Macrospondylus and Clovesuurdameredeor); external nares oriented anterodorsally (shared with Plagiophthalmosuchus, the Chinese teleosauroid, Indosinosuchus, Teleosaurus, Mycterosuchus, Aeolodon, Bathysuchus and Sericodon); the premaxilla anterior and anterolateral margins are orientated anteroventrally and extend ventrally (shared with Mystriosaurus, the Chinese teleosauroid, Indosinosuchus, Teleosaurus, Mycterosuchus, Aeolodon, Bathysuchus and Sericodon); presence of small, mediolaterally thin antorbital fenestrae; anterior margin of the supratemporal fossae are noticeably inclined anterolaterally (shared with Mystriosaurus, the Chinese teleosauroid, Indosinosuchus, Teleosaurus, Mycterosuchus, Aeolodon, Bathysuchus and Sericodon); frontal width is broader than orbital width (shared with Plagiophthalmosuchus, Mystriosaurus, Teleosaurus, Mycterosuchus, Bathysuchus, Aeolodon, Pr. cf. bouchardi, Neosteneosaurus, Mac. buffetauti and Mac. mosae); frontal-postorbital suture is lower than the intertemporal bar (shared with Teleosaurus); orbits are longitudinal ellipsoid in shape (shared with Plagiophthalmosuchus, the Chinese teleosauroid, Aeolodon, Macrospondylus, Charitomenosuchus, Seldsienean, Proexochokefalos, Deslongchampsina and Neosteneosaurus); postorbital reaches the orbit posteroventral margin and forms an extensive area of the orbit ventral margin (shared with Mystriosaurus, Indosinosuchus, the Chinese teleosauroid, Teleosaurus and Mycterosuchus); five premaxillary alveoli (shared with Teleosaurus, Bathysuchus and Sericodon); interalveolar spacing between P1-P2 and P3-P4 relatively the same size (shared with Mycterosuchus, Bathysuchus and Sericodon); anterior maxillary teeth procumbent (shared with Plagiophthalmosuchus, I. kalasinensis, Teleosaurus, Sericodon, Aeolodon, Macrospondylus and Charitomenosuchus);neural spine height is greater than centrum height (similar to Neosteneosaurus); tuberculum of dorsal rib situated on the medial edge (shared with Aeolodon, Macrospondylus and Lemmysuchus); shortened and squat scapula (similar to Macrospondylus); proximal humerus posteriorly expanded and weakly hooked (shared with Teleosaurus); forelimb relatively shorter than hindlimb by approximately 22% (similar to Macrospondylus); tibia shorter than the femur by approximately 25% (similar to Macrospondylus); small round to ellipsoid pits on all osteoderms that are very densely distributed, with a ‘honeycomb’ pattern (shared with Teleosaurus); presacral osteoderms are strongly curved and closely locked together, forming a dorsal ‘shield’ (shared with Teleosaurus).

Teleosaurus Geoffroy Saint-Hilaire, 1825

Type species—Crocodilus cadomensis Lamouroux, 1820. Now referred to as Teleosaurus cadomensis (Lamouroux, 1820), Geoffroy Saint-Hilaire, 1825.

Etymology—‘Perfect lizard’. Teleo is from the Anceint Greek téleios (τέλειος) meaning perfect, and saurus is the Latinized version of saûros (σαυρoς), which is Ancient Greek for lizard or reptile.

Teleosaurus cadomensis Lamouroux, 1820

(Fig. 7)

Holotype—MNHN.F AC 8746, a partially complete skull, with associated postcranial material. The specimen was initially found by Pierre Tesson, who traded it to Lamouroux. Lamouroux briefly noted it (1820) and then sent the specimen to Georges Cuvier. It was fully described by Cuvier (1824) and Geoffroy Saint-Hilaire (1825). See Brignon (2018a) for more details.

Referred material—NHMUK PV OR 119a (dorsal osteoderms); NHMUK PV R 4207 (dorsal osteoderms); NHMUK PV OR 32588 (dorsal, sacral and caudal vertebrae); NHMUK PV OR 32657 (femur); NHMUK PV OR 32680 (ischium); NHMUK PV OR 33124 (mandibular symphysis); NHMUK PV OR 39788 (partial rostrum); and additional casts (e.g. NHMUK PV R 880; NHMUK PV R 880a).

Age—Bathonian, Middle Jurassic.

Locality—Allemagne, 3 km south of Caen, Calvados, Normandy, France.

Stratigraphic horizon—‘Calcaire de Caen’.

Scoring sources—the neotype and all referred material mentioned above was studied first-hand. Lamouroux (1820), Geoffroy Saint-Hilaire (1825), Eudes-Deslongchamps (1867), Vignaud (1995) and Jouve (2009) provided additional information.

Autapomorphic characters of T. cadomensis—small, subcircular, shallow antorbital fenestrae; supratemporal fenestrae box- or square-shaped; postorbital and squamosal are relatively the same length, with the squamosal being slightly longer (~10%); choanae mediolaterally wider than palatines.

Emended diagnosis—longirostrine, gracile snout; tooth row and quadrate condyle unaligned with the tooth row at a lower level, and both below the occipital condyle (shared with Platysuchus); tooth row at a lower level than the quadrate (shared with Plagiophthalmosuchus, Indosinosuchus, Platysuchus, Mycterosuchus and Macrospondylus); rostrum narrows immediately anterior to the orbits (shared with I. potamosiamensis, Mycterosuchus, Aeolodon, Bathysuchus, Sericodon and Seldsienean); frontal ornamentation extends from the centre to lateral- and anterior-most regions (shared with Plagiophthalmosuchus, the Chinese teleosauroid, Indosinosuchus, Platysuchus, Mycterosuchus, Macrospondylus and Clovesuurdameredeor); external nares oriented anterodorsally (shared with Plagiophthalmosuchus, the Chinese teleosauroid, Indosinosuchus, Platysuchus, Mycterosuchus, Aeolodon, Bathysuchus and Sericodon); premaxilla anterior and anterolateral margins of are orientated anteroventrally and extend ventrally (shared with Mystriosaurus, the Chinese teleosauroid, Indosinosuchus, Platysuchus, Mycterosuchus, Aeolodon, Bathysuchus and Sericodon); anterior margin of the supratemporal fossae are noticeably inclined anterolaterally (shared with Mystriosaurus, the Chinese teleosauroid, Indosinosuchus, Platysuchus, Mycterosuchus, Bathysuchus and Aeolodon); anteromedial projection of the frontal is relatively broad but becomes instantly mediolaterally thin at the anterior-most part (shared with Sericodon); frontal width is broader than orbital width (shared with Plagiophthalmosuchus, Mystriosaurus, Platysuchus, Mycterosuchus, Bathysuchus, Aeolodon, Pr. cf. bouchardi, Neosteneosaurus, Mac. buffetauti and Mac. mosae); frontal-postorbital suture is lower than the intertemporal bar (shared with Platysuchus); dorsal margins of orbits upturned (shared with I. potamosiamensis, Mycterosuchus and Aeolodon); postorbital reaches the orbit posteroventral margin and forms an extensive area of the orbit ventral margin (shared with Mystriosaurus, Indosinosuchus, the Chinese teleosauroid, Platysuchus and Mycterosuchus); pterygoid flange oriented horizontally (shared with the Chinese teleosauroid); five premaxillary alveolar pairs (shared with Platysuchus, Bathysuchus and Sericodon); anterior maxillary teeth procumbent (shared with Indosinosuchus, Platysuchus, Aeolodon, Sericodon, Macrospondylus and Charitomenosuchus); proximal humerus posteriorly expanded and weakly hooked (shared with Platysuchus); small round to ellipsoid pits that are very densely distributed, with a ‘honeycomb’ pattern (shared with Platysuchus); presacral osteoderms are strongly curved and closely locked together, forming a dorsal ‘shield’ (shared with Platysuchus).

Remarks—the genus Teleosaurus, initially defined by Geoffroy Saint-Hilaire (1825), has encompassed numerous species throughout its long history, such as T. gladius, T. subulidens, T. geoffroyi, T. minimus and T. eucephalus (Quenstedt, 1852; Phillips, 1871; Seeley, 1880; Eudes-Deslongchamps, 1868c). However, the majority of these historic Teleosaurus species are currently considered invalid due to the following propositions: (1) thought to be juveniles or sub-adults, and therefore subjective junior synonyms of T. cadomensis (e.g. Jouve, 2009); (2) uncertainty of teleosauroid ontogenetic stages and sexual dimorphism (see Johnson, Young & Brusatte, 2020); and (3) loss of original material. Therefore, we currently only recognize T. cadomensis as a valid species; the issue regarding the validity of other ‘Teleosaurus’ species is beyond the scope of this manuscript.

Mycterosuchus Andrews, 1913

Type species—Steneosaurus nasutus Andrews, 1909. Now referred to as Mycterosuchus nasutus (Andrews, 1909), Andrews, 1913.

Etymology—‘(Long) Nose crocodile’. Myctero comes from the Latin mycto meaning nose, referring to the elongated rostrum of this taxon; suchus is the Latinized form of the Greek soukhos (σοῦχος), meaning crocodile.

Diagnosis—same as the only known species (monotypic genus).

Mycterosuchus nasutus (Andrews, 1909) Andrews, 1913

(Fig. 8)

Holotype—NHMUK PV R 2167, a complete skull and mandible, with additional material (including vertebrae (cervical, dorsal, sacral and caudal), cervical and dorsal ribs, scapulocoracoid, two partial femora, one radius, one ulna, multiple phalanges and tarsals, isolated teeth and multiple dorsal osteoderms).

Referred material—CAMSM J.1420 (nearly complete skeleton); NHMUK PV R 3892 (dorsal and sacral vertebrae); NHMUK PV R 4059 (partial skull); unnumbered GZG specimen (complete skull). Possible NM partial skeleton (catalogue number unknown, photographs provided by B. Ekrt).

Age—Middle Callovian, Middle Jurassic.

Locality—Peterborough, UK.

Stratigraphic horizon—Peterborough Member, Oxford Clay Formation, Ancholme Group.

Scoring sources—the holotype (NHMUK PV R 2167) and all referred material (excluding the NM skeleton) mentioned above were studied first-hand.

Autapomorphic characters of Myc. nasutus—overall cranium and mandible extremely rugose; elongate, slender rostrum (approximately 73% of total skull length); maxilla ornamented with an array of irregular patterns of deep rugosities and anastomosing grooves; reduced quadrate condyles; palatine anterior margin terminates level to 29th maxillary alveoli, or more distal alveoli; curvature of the angular is gradual in the anterior region, but more abrupt in the posterior-most region; on the retroarticular process, the length of the attachment surface for the adductor muscles is more than twice its width; D1 strongly anteriorly oriented; the neural arches of the posterior cervical vertebrae are taller than the vertebral centra; the posterior edge of the scapula is more strongly concave than the anterior edge; the humeral head is weakly posteriorly expanded and hooked with a club-like shape; the ulna is more than 25% longer than the radius; the pubic shaft is over 50% length of the pubic plate; anteromedial tuber of the femur is the largest of the proximal tubera; size of calcaneal tuber approximately 25% of total astragalus size; large, heavyset dorsal osteoderms with large, round-to-ellipsoid (D-shaped) irregular pits that are well separated from one another.

Emended diagnosis—longirostrine snout; tooth row and quadrate condyle unaligned and quadrate at a lower level, but both below the occipital condyle (shared with Indosinosuchus taxa); well-developed and extensive ornamentation on the premaxillae, maxillae, frontal, prefrontal, lacrimal and postorbital; frontal ornamentation composed of small sub-circular to elongate pits that are closely spaced or, that can fuse and become a ridge-groove pattern (similar to Mystriosaurus); rostrum narrows immediately anterior to the orbits (shared with I. potamosiamensis, Teleosaurus, Aeolodon, Bathysuchus, Sericodon and Seldsienean); premaxilla anterior and anterolateral margins are strongly anteroventrally deflected and extend ventrally (shared with Mystriosaurus, the Chinese teleosauroid, Indosinosuchus, Platysuchus, Teleosaurus, Aeolodon, Bathysuchus and Sericodon); more than 67% of total premaxilla length is posterior to the external nares (shared with Plagiophthalmosuchus, I. potamosiamensis, the Chinese teleosauroid, Aeolodon, Bathysuchus and Sericodon); external nares are ‘8’ shaped in dorsal view due to enlarged anterior and posterior projections of the premaxilla (shared with Bathysuchus); external nares are anterodorsally oriented (shared with Mystriosaurus, the Chinese teleosauroid, Platysuchus and Bathysuchus); clustering of large, circular foramina along lateral margin of external nares (similar to Mystriosaurus, I. kalasinensis and Machimosaurini); small, subcircular antorbital fenestrae; the anterior margin of the supratemporal fossae are noticeably inclined anterolaterally (shared with Mystriosaurus, the Chinese teleosauroid, Indosinosuchus, Platysuchus, Teleosaurus, Aeolodon, Bathysuchus and Sericodon); frontal width broader than orbital width (shared with Plagiophthalmosuchus, Mystriosaurus, Platysuchus, Teleosaurus, Bathysuchus, Aeolodon, Neosteneosaurus, Mac. buffetauti and Mac. mosae); circular orbits (shared with Mystriosaurus, Teleosaurus, Indosinosuchus, Clovesuurdameredeor and Machimosaurini); dorsal margins of orbits are upturned (shared with I. potamosiamensis, Teleosaurus and Aeolodon); postorbital reaches the orbit posteroventral margin and extensively forms part of the orbit ventral margin (shared with Mystriosaurus, the Chinese teleosauroid, I. potamosiamensis, Platysuchus and Teleosaurus); reduced basioccipital tubera (similar to Plagiophthalmosuchus, Bathysuchus and Sericodon); mandibular symphysis over 50% of mandible length (shared with Bathysuchus, Aeolodon, Macrospondylus, Seldsienean and Charitomenosuchus); mandibular symphysis depth is very narrow, approximately 4–4.5% of the mandible length (shared with Charitomenosuchus); the P1 and P2 do not form a couplet, and the interalveolar spacing between the P1-P2 and P3-P4 are relatively the same size (shared with Platysuchus, Bathysuchus and Sericodon); both the P1 and P2 alveoli are oriented laterally (shared with Bathysuchus and Sericodon); the P1 and P2 do not form a couplet but are still oriented on the anterior margin of the premaxilla (shared with Bathysuchus and Sericodon); P1 and P2 are on the same transvers plane (shared with Aeolodon, Bathysuchus and Sericodon); teeth slender, pointed and weekly mediolaterally compressed (shared with Bathysuchus and Aeolodon); the tubercula and articular facets in the dorsal ribs are positioned directly in the middle (shared with Charitomenosuchus); the tubercula in the dorsal ribs are large and pronounced (shared with Neosteneosaurus and Machimosaurini); tibia approximately 40–50% shorter than the femur (shared with Charitomenosuchus, Neosteneosaurus and Machimosaurini); the medial femoral condyle is noticeably larger than the lateral femoral condyle (shared with Charitomenosuchus and Neosteneosaurus).

Remarks—the skull and mandible of the NHMUK holotype was originally numbered PV R 2617, along with the associated postcranial material. The skull and mandible were then reregistered PV R 3577 in error (what year and by whom is unknown). Mycterosuchus has also been considered as a synonym of Steneosaurus leedsi (= Charitomenosuchus leedsi) in certain studies (Vignaud, 1995).

Aeolodon Von Meyer, 1832

Type species—Crocodilus priscus Von Sömmerring, 1814. Now referred to as Aeolodon priscus (Von Sömmerring, 1814), Von Meyer, 1832.

Etymology—‘Changeful tooth’. Aeolo comes from the Ancient Greek aiólos (αἰόλος) meaning changeful, and don from the Greek dónti (δόντι) meaning tooth. Von Meyer (1832) wrote that he used this name based on the holotype’s “heterodont teeth”.

Diagnosis—same as the only known species (monotypic genus).

Aeolodon priscus (Von Sömmerring, 1814) Von Meyer, 1832

(Fig. 9)

Holotype—NMHUK PV R 1086, a nearly complete skeleton.

Referred material—MNHN.F.CNJ 78 (nearly complete skeleton).

Age—lower Tithonian, Late Jurassic.

Localities—Daiting, southern Germany; Canjuers, Var, France.

Stratigraphic horizons—Mörnsheim Formation; Canjuers conservation Lagerstätte.

Scoring sources—the holotype (NMHUK PV R 1086) and referred specimen (MNHN.F.CNJ 78a) were both studied first-hand.

Autapomorphic characters of A. priscus—shallow elliptical pits on the frontal; length of the attachment surface for the m. pterygoideus posterior on the retroarticular process is short, and subequal to its width; neural spine and centrum heights of the mid-cervical vertebrae are approximately equal; distal coracoid with rounded edges and a deep coracoid foramen; extremely shortened ulna and radius relative to humerus; ulna with little curvature, only in the proximal-most region; metacarpals IV and V are similar in robusticity to II-III ; ischial plate sub-triangular; tibia 30–40% shorter than the femur; dorsal osteoderm ornamentation consists of large, well-spaced circular pits.

Emended diagnosis—longirostrine skull; rostrum narrows immediately anterior to the orbits (shared with I. potamosiamensis, Teleosaurus, Mycterosuchus, Bathysuchus, Sericodon and Seldsienean); shallow, inconspicuous ornamentation of the premaxillae and maxillae (similar to the Chinese teleosauroid, Indosinosuchus, Bathysuchus and Sericodon); no ornamentation on the prefrontal (shared with Plagiophthalmosuchus, I. potamosiamensis, Bathysuchus and Sericodon) and lacrimal (shared with Plagiophthalmosuchus, I. potamosiamensis, Sericodon, Macrospondylus and Charitomenosuchus); frontal ornamentation restricted to centre (shared with Sericodon, Charitomenosuchus, Seldsienean, Deslongchampsina, Proexochokefalos, Neosteneosaurus and Machimosaurini); external nares oriented anterodorsally (shared with the Chinese teleosauroid, Indosinosuchus, Platysuchus, Teleosaurus, Mycterosuchus, Bathysuchus and Sericodon); external nares noticeably ‘8’-shaped in anterior view (shared with Mystriosaurus, the Chinese teleosauroid, I. potamosiamensis and Bathysuchus); the premaxilla anterior and anterolateral margins are orientated anteroventrally and extend ventrally (shared with Mystriosaurus, the Chinese teleosauroid, Indosinosuchus, Platysuchus, Teleosaurus, Mycterosuchus, Bathysuchus and Sericodon); sub-rectangular supratemporal fenestrae; the anterior margin of the supratemporal fossae are noticeably inclined anterolaterally (shared with Mystriosaurus, the Chinese teleosauroid, Indosinosuchus, Platysuchus, Teleosaurus, Mycterosuchus, Bathysuchus and Sericodon); frontal width is broader than orbital width (shared with Plagiophthalmosuchus, Mystriosaurus, Platysuchus, Teleosaurus, Mycterosuchus, Bathysuchus, Pr. cf. bouchardi, Neosteneosaurus, Mac. buffetauti and Mac. mosae); orbits are longitudinal ellipsoid in shape (shared with Plagiophthalmosuchus, the Chinese teleosauroid, Platysuchus, Macrospondylus, Charitomenosuchus, Seldsienean, Proexochokefalos, Deslongchampsina and Neosteneosaurus); the dorsal margins of the orbits are upturned (shared with I. potamosiamensis, Teleosaurus and Mycterosuchus); angular poorly curved (somewhat similar to Plagiophthalmosuchus and Mystriosaurus); mandibular symphysis is over 50% of the mandible length (shared with Mycterosuchus, Bathysuchus, Macrospondylus, Charitomenosuchus and Seldsienean); retroarticular width subequal to the glenoid fossa (shared with Lemmysuchus and Mac. buffetauti); P1 and P2 are both on the same transverse plane (shared with Mycterosuchus, Bathysuchus and Sericodon); the premaxilla lateral margins are sub-rectangular, with the P3 alveoli being clearly lateral to the P2 alveoli (shared with Mycterosuchus, Bathysuchus and Sericodon); at least 22 dentary alveolar pairs; premaxillary and anterior maxillary apicobasal length to basal width ratio of the tooth crown is 3 or greater (shared with Macrospondylus and Charitomenosuchus); shallow tuberculum on the dorsal ribs (shared with Macrospondylus and Charitomenosuchus); the proximal region of the humerus is very strongly posteriorly deflected and hooked (shared with Charitomenosuchus and Neosteneosaurus); femoral condyles are relatively the same size (shared with Macrospondylus, Platysuchus and Lemmysuchus); pits on dorsal osteoderms arranged in alternating rows (similar to Bathysuchus); dorsal osteoderms reduced in size and thickness (shared with Bathysuchus).

Remarks—Crocodilus priscus (NHMUK PV R 1086) was the first teleosauroid genus to be scientifically named by von Sömmering in 1814. Von Meyer (1830) initially presented Aeolodon gen. nov., and prematurely used this genus for comparison with Rhacheosaurus (1831: 176) but did not provide a formal description until his 1832 volume. Comparing the specimen (NHMUK PV R 1086) to the modern gharial, Von Meyer (1832) noted the “heterodont” teeth (which was his basis for the new genus name) and the “limb bones and phalanges […] appear like in whales”. It is also interesting to note that Geoffroy Saint-Hilaire (1831: 48) did not believe that Aeolodon (“le gavial de Sömmering”: “Sömmering’s gavial”) could be referred to as either Teleosaurus or ‘Steneosaurus’ (mainly due to the fact that it was not found in the deposits near Caen, which Geoffroy Saint-Hilaire believed these two genera were restricted to).

Despite coming from different localities, the holotype (NHMUK PV R 1086) and referred specimen (MNHN.F.CNJ 78) share the following combination of features:

1. A longirostrine, weakly ornamented skull;

2. Protruding orbits;

3. Neural spine and centrum of the mid-cervical vertebrae are approximately equal in height;

4. Distal coracoid with rounded edges and deep coracoid foramen;

5. An elongated ilial process, more so than other teleosauroids (e.g. Charitomenosuchus NHMUK PV R 3806);

6. A sub-triangular ischial blade; and

7. Reduced dorsal ornamentation on osteoderms, with large, shallow, well-spaced pits.

Bathysuchus Foffa et al., 2019

Type species—Teleosaurus megahinus Hulke, 1871. Now referred to as Bathysuchus megarhinus (Hulke, 1871), Foffa et al., 2019.

Etymology—‘Deep water crocodile’. Bathys, or vathys (βαθυς) is Ancient Greek for deep, and suchus is the Latinized form of the Greek soukhos (σοῦχος), meaning crocodile.

Diagnosis—same as the only known species (monotypic genus).

Bathysuchus megarhinus (Hulke, 1871) Foffa et al., 2019

(Fig. 10)

Holotype—NHMUK PV OR 43086, a partial rostrum.

Referred material—DORCM G.05067i-v (premaxillae, isolated tooth and partial osteoderm), LPP unnumbered specimen (a partial rostrum, mandible and skull).

Age—Aulacostephanus autissiodorensis Sub-Boreal ammonite Zone and Au. eudoxus ammonite Zone, late Kimmeridgian, Late Jurassic.

Locality—Kimmeridge, Dorset, UK; Francoulés, Quercy, France.

Stratigraphic horizon—Dorset succession, lower Kimmeridge Clay Formation, Ancholme Group; between the Quercynum Horizon and the Contejeani Horizon (Hantzpergue & Lafaurie, 1983).

Scoring sources—the holotype (NHMUK PV OR 43086) and the unnumbered LPP specimen were studied first-hand. D. Foffa provided high quality photographs of DORCM G.05067i-v, and B. megarhinus was also discussed at great length with D. Foffa.

Autapomorphic characters of B. megarhinus—shallow, minor ornamentation on the parietal (nearly imperceptible); extremely pronounced lateral expansion of the premaxilla with rounded, straightened lateral margins; the fifth dentary alveolar pair is posterolaterally oriented and on the posterior end of the mandibular spatula

Emended diagnosis—longirostrine snout; rostrum narrows immediately anterior to the orbits (shared with I. potamosiamensis, Teleosaurus, Mycterosuchus, Sericodon, Aeolodon and Seldsienean); shallow, inconspicuous ornamentation of the premaxillae and maxillae (similar to the Chinese teleosauroid, Indosinosuchus, Sericodon and Aeolodon); no ornamentation on the prefrontal (shared with Plagiophthalmosuchus, I. potamosiamensis, Sericodon and Aeolodon); external nares are ‘8’ shaped in dorsal view (shared with Mystriosaurus, the Chinese teleosauroid, I. potamosiamensis, Mycterosuchus and Aeolodon) and in anterior view (shared with Mystriosaurus, the Chinese teleosauroid, I. potamosiamensis and Aeolodon); external nares are anterodorsally oriented (shared with Plagiophthalmosuchus, the Chinese teleosauroid, Indosinosuchus, Platysuchus, Mycterosuchus, Aeolodon, Bathysuchus and Sericodon); reduced anteroposterior length of the external nares; more than 67% of total premaxilla length is posterior to the external nares (shared with Plagiophthalmosuchus, the Chinese teleosauroid, I. potamosiamensis, Mycterosuchus, Sericodon and Aeolodon); premaxillary anterior and posterior medial margin of external nares formed by two bulbous projections (shared with Mycterosuchus); the anterior and anterolateral margins of the premaxillae are strongly anteroventrally deflected and extend ventrally (shared with Mystriosaurus, the Chinese teleosauroid, Mycterosuchus and Platysuchus); inconspicuously ornamented maxillary dorsal surface (shared with the Chinese teleosauroid and Aeolodon), consisting of a shallow irregular pattern of ridges and anastomosing grooves; nasal, prefrontal, lacrimal are also inconspicuously ornamented; absence/extremely reduced frontal ornamentation (shared with Aeolodon); the rostrum narrows markedly immediately anterior to the orbits (shared with I. potamosiamensis, Teleosaurus and Mycterosuchus); frontal width is broader than the orbital width (shared with Plagiophthalmosuchus, Mystriosaurus, Platysuchus, Teleosaurus, Mycterosuchus, Aeolodon, Pr. cf. bouchardi, Neosteneosaurus, Mac. buffetauti and Mac. mosae); palatine anterior margin terminates distal to the 20th maxillary alveoli (shared with Mycterosuchus); basioccipital tubera reduced (shared with Plagiophthalmosuchus, Mycterosuchus and Sericodon); mandibular symphysis over 50% of mandible length (shared with Mycterosuchus, Aeolodon, Macrospondylus, Seldsienean and Charitomenosuchus); premaxillae with five alveoli (shared with Platysuchus, Teleosaurus and Sericodon); the P1–P2 do not form a couplet (shared with Platysuchus, Mycterosuchus and Sericodon); the P3–P4 do not form a couple (shared with the Chinese teleosauroid); the P1 and P2 alveoli are lateral to each other at the anterior margin of the premaxilla (shared with Mycterosuchus, Sericodon and possibly Aeolodon); the P3 and P4 are aligned on the lateral plane of the external margin more so than P2 (shared with Sericodon); the P1 and P2 are on the same transverse plane, and the lateral margin between the P2 and P3 is sub-rectangular (shared with Mycterosuchus, Sericodon and Aeolodon); anterior maxillary interalveolar spacing is sub-equal to longer than adjacent alveoli; lack of apical tooth carinae (shared with Sericodon); the pits on the dorsal osteoderms are circular and regularly organised in alternate rows (similar with Aeolodon); dorsal osteoderms reduced in size and thickness (shared with Aeolodon).

Remarks—Steneosaurus megarhinus was initially named and described by Hulke (1871) and was recently re-described within a new monotypic genus, Bathysuchus, by Foffa et al. (2019). Due to similar anatomical features of the cranium, stratigraphic horizons, and comparative measurements of the humerus and femur with Aeolodon, Foffa et al. (2019) concluded that these two genera were evidence of the first deep water, more pelagic teleosauroids.

Sericodon Von Meyer, 1845

Type species—Sericodon jugleri Von Meyer, 1845.

Etymology—‘Silk toothed’, Serico comes from the Latin sēricus (Ancient Greek: Sêres [Σῆρες], possibly from Ancient Chinese ) meaning silk, and don from the Greek dónti (δόντι) meaning tooth. Refers to the slender, poorly ornamented dentition of this taxon.

Diagnosis—same as the only known species (monotypic genus).

Sericodon jugleri Von Meyer, 1845

(Fig. 11)

Type series—Isolated teeth from Hannover (Germany) and Solothurn (Switzerland). Catalogue numbers currently unknown.

Taxonomic note—Von Meyer (1845) initially diagnosed a series of teeth from the Kimmeridgian of Solothurn and Hannover as the type series of Sericodon; however, it is unknown if this material is still available, and Von Meyer did not designate a holotype. A lectotype can be proposed for one of the NMS (Switzerland) specimens, but this needs further clarification. The authors and colleagues plan a thorough description of this specimen, as well as additional Sericodon material, to allow for a formal designation of a lectotype.

Referred material—BSY006-348, BSY007-134, BSY008-622, SCR010-312, SCR010-1184, SCR011-2460, SCR011-406, TCH005-151 TCH007-215, VTT006-171 (see Schaefer, Püntener & Billon-Bruyat, 2018), as well as LM 16645-46 (anterior mandible), NHMUK PV R 1752, NZM-PZ R2337, SMF R 431a-b, SMF R 4318 (isolated teeth), unnumbered Göttingen specimen (partial skull).

Age—late Kimmeridgian to early Tithonian, Late Jurassic.

Localities—Courtedoux-Bois de Sylleux, Courtedoux-sur Combe Ronde, Courtedoux-Tchâfouè and Courtedoux-Vâ Tche Tchâ, northwestern Switzerland; Hannover, Germany.

Stratigraphic horizon—Reuchenette Formation.

Scoring sources—Majority of material was scored using Schaefer, Püntener & Billon-Bruyat (2018). Additional specimens (LM 16645-46, NHMUK PV R 1752, NRM-PZ R2337, SMF R 431a-b, SMF R 4318, unnumbered Göttingen specimen) were examined first-hand.

Autapomorphic characters of Ser. jugleri—unornamented intertemporal bar; external nares weakly subcircular in dorsal view; palatal canals extremely shallow; lack of apical enamel ridges; tuberculum and articular facet of dorsal rib situated close to the lateromedial edge; posteromedial tuber of femur reduced.

Emended diagnosis—longirostrine snout; rostrum narrows immediately anterior to orbits (shared with I. potamosiamensis, Teleosaurus, Bathysuchus, Mycterosuchus and Aeolodon); no conspicuous ornamentation on both the prefrontal (shared with Plagiophthalmosuchus, I. potamosiamensis, Bathysuchus and Aeolodon) and lacrimal (shared with Plagiophthalmosuchus, I. potamosiamensis, Aeolodon and Macrospondylus); frontal ornamentation restricted to centre (shared with Aeolodon, Charitomenosuchus, Seldsienean, Deslongchampsina, Proexochokefalos, Neosteneosaurus and Machimosaurini); external nares oriented anterodorsally (shared with Plagiophthalmosuchus, the Chinese teleosauroid, Indosinosuchus, Platysuchus, Mycterosuchus, Aeolodon and Bathysuchus); over 67% of total premaxilla length is posterior to the external nares (shared with Plagiophthalmosuchus, the Chinese teleosauroid, I. potamosiamensis, Mycterosuchus, Bathysuchus and Aeolodon); anteromedial projection of the frontal is relatively broad but becomes immediately mediolaterally thin at the anterior-most part (shared with Teleosaurus); basioccipital tubera reduced (shared with Plagiophthalmosuchus, Mycterosuchus and Bathysuchus); five premaxillary alveolar pairs (shared with Platysuchus, Teleosaurus and Bathysuchus); the P1 and P2 alveoli are lateral to each other at the anterior margin of the premaxilla (shared with Mycterosuchus, Bathysuchus and possibly Aeolodon); the P3 and P4 are aligned on the lateral plane of the external margin more so than P2 (shared with Bathysuchus); the P1 and P2 are on the same transverse plane, and the lateral margin between the P2 and P3 is sub-rectangular (shared with Mycterosuchus, Bathysuchus and Aeolodon); lack of apical carinae (shared with Bathysuchus); shallow tuberculum (shared with Aeolodon, Macrospondylus and Charitomenosuchus); postacetabular iliac process elongated (shared with Plagiophthalmosuchus, Platysuchus, Teleosaurus and Macrospondylus); dorsal osteoderm pits are subcircular and organised in sub-parallel rows.

Remarks—Sericodon was initially diagnosed by Von Meyer (1845) but since the late 1800s has been considered a subjective junior synonym of ‘Steneosaurus’ (Sauvage, 1896; Sauvage, 1897; Von Huene, 1926; Kuhn, 1936; Steel, 1973; Buffetaut et al., 1985). Sericodon differs from Bathysuchus in the following characteristics:

1. Sericodon (TCH005-151; Schaefer, Püntener & Billon-Bruyat, 2018) lacks enamel ridges on the apices of the dentition, whereas Bathysuchus possesses faint but present enamel ridges (DORCM G.05067iv);

2. The lateral margins of the premaxillae are more expanded and sub-rectangular in Bathysuchus (NHMUK PV OR 43086; unnumbered LPP specimen). In Sericodon (SCR011-406; Schaefer, Püntener & Billon-Bruyat, 2018) they are less laterally expanded with more rounded margins;

3. Frontal ornamentation is present in Sericodon (SCR010-312; Schaefer, Püntener & Billon-Bruyat, 2018) but is absent in Bathysuchus (unnumbered LPP specimen), in specimens of approximately equal size;

4. A distinct groove between the two distinct quadrate condyles is present in Sericodon (SCR010-312; Schaefer, Püntener & Billon-Bruyat, 2018), whereas in Bathysuchus (unnumbered LPP specimen) the groove is nearly non-existent (although this may be due to preservation); and

5. The P3 alveoli is substantially larger than both the P1 and P2 in Sericodon (SCR011-406; Schaefer, Püntener & Billon-Bruyat, 2018). In Bathysuchus (DORCM G.05067i), the P3 is relatively the same size as the P2 and slightly larger than the P1.

6. Finally, Sericodon and Bathysuchus are always stable sister taxa in the phylogeny (see below), regardless of teleosauroid taxa and/or characters added or removed.

Indosinosuchus Martin et al., 2019

Type species—Indosinosuchus potamosiamensis Martin et al., 2019.

Etymology—‘Indochinese crocodile’. Refers to the Indochinese micro-tectonic block where the fossil was discovered, and suchus is the Latinized form of the Greek soukhos (σοῦχος), meaning crocodile.

Diagnosis—tooth row and quadrate condyle are unaligned with quadrate at a lower level, but both are below the occipital condyle; faint to no conspicuous maxillary ornamentation; approximately 30 alveoli per dentary.

Indosinosuchus potamosiamensis Martin et al., 2019

(Fig. 12)

Holotype—PRC-11, a complete skull and mandible.

Referred material—PRC-238

Age—Late Jurassic (exact age is unknown, hypothesised to be Tithonian).

Locality—Pho Noi, Phu Phan range, Kham Muang District, Kalasin Province, northeastern Thailand.

Stratigraphic horizon—lower part of the Phu Kradung Formation, Khorat Group.

Scoring sources—the holotype (PRC-11) as well as PRC-238 were examined first-hand. Additional information was gleaned from Martin et al. (2019).

Autapomorphic characters of I. potamosiamensis—extremely anteroposteriorly elongated posterior nasal processes (reaching the medial margin of the orbit); substantially elongated anterior process of the nasal, near-parallel to the posterior margin of the antorbital fenestra; the D2–D3 interalveolar space is longer than that between the D1 and D2.

Emended diagnosis—mesorostrine snout; tooth row and quadrate condyle unaligned with quadrate at a lower level, and both below the occipital condyle (shared with I. kalasinensis and Mycterosuchus); tooth row at a lower level than occipital condyle (shared with Plagiophthalmosuchus, I. kalasinensis, Platysuchus, Teleosaurus, Mycterosuchus and Macrospondylus); rostrum narrows immediately anterior to orbits (shared with Teleosaurus, Mycterosuchus, Aeolodon, Bathysuchus and Sericodon); shallow, irregular maxillary ornamentation consisting of grooves (similar to the Chinese teleosauroid, Bathysuchus and Aeolodon); no conspicuous ornamentation on both the prefrontal and lacrimal (similar to Plagiophthalmosuchus, Aeolodon and Sericodon); frontal ornamentation extends from the centre to lateral- and anterior-most regions (shared with Plagiophthalmosuchus, the Chinese teleosauroid, I. kalasinensis, Platysuchus, Teleosaurus, Mycterosuchus, Macrospondylus and Clovesuurdameredeor); external nares oriented anterodorsally (shared with the Chinese teleosauroid, I. kalasinensis, Platysuchus, Mycterosuchus, Aeolodon, Bathysuchus and Sericodon); over 67% of premaxilla total length is posterior to the external nares (shared with Plagiophthalmosuchus, the Chinese teleosauroid, Mycterosuchus, Bathysuchus, Sericodon and Aeolodon); presence of small, oval-shaped antorbital fenestrae; anterior margin of the supratemporal fossae are noticeably inclined anterolaterally (shared with Mystriosaurus, the Chinese teleosauroid, I. kalasinensis, Platysuchus, Teleosaurus, Mycterosuchus, Bathysuchus and Aeolodon); frontal width narrower than orbital width (shared with Charitomenosuchus); dorsal margins of orbits upturned (shared with Teleosaurus, Mycterosuchus and Aeolodon); postorbital reaches the orbit posteroventral margin and forms an extensive area of the orbit ventral margin (shared with Mystriosaurus, the Chinese teleosauroid, Platysuchus, Teleosaurus and Mycterosuchus); palatine anterior margin terminates level to 17th or 18th maxillary alveoli (similar to Charitomenosuchus and Mac. buffetauti); symphysis under half of mandible length, between 0.45 and 0.5 (shared with Mystriosaurus, Deslongchampsina and Proexochokefalos); mandibular fenestra anteroposteriorly small and poorly elliptic (similar to Mystriosaurus); at least 27 maxillary alveolar pairs; third premaxillary alveolus are enlarged relative to adjacent alveoli (shared with the Chinese teleosauroid); at least 30 dentary alveoli.

Indosinosuchus kalasinensis sp. nov.

(Fig. 13)

Holotype—PRC-239, a nearly complete skull and mandible.

Etymology—the specific epithet refers to the Kalasin Province in northeastern Thailand where the holotype was found. urn:lsid:zoobank.org:act:2B7DB5BB-1F93-457F-A295-0409ECCD3998

Age—Late Jurassic (exact age is unknown, hypothesised to be Tithonian).

Locality—Pho Noi, Phu Phan range, Kham Muang District, Kalasin Province, northeastern Thailand.

Stratigraphic horizon—lower part of the Phu Kradung Formation, Khorat Group.

Scoring Sources—PRC-239 was examined first-hand.

Autapomorphic characters of I. kalasinensis—approximately 64% of total premaxilla length is posterior to the external nares; anteroposteriorly thickened postorbital bar.

Emended diagnosis—mesorostrine snout; tooth row and quadrate condyle unaligned with quadrate at a lower level, and both below the occipital condyle (shared with I. potamosiamensis and Mycterosuchus); tooth row at a lower level than occipital condyle (shared with Plagiophthalmosuchus, I. potamosiamensis, Platysuchus, Teleosaurus, Mycterosuchus and Macrospondylus); premaxilla and maxilla ornamented with shallow ridges (similar to the Chinese teleosauroid, I. potamosiamensis, Bathysuchus, Sericodon and Aeolodon); frontal ornamentation extends from the centre to lateral- and anterior-most regions (shared with Plagiophthalmosuchus, the Chinese teleosauroid, I. potamosiamensis, Platysuchus, Teleosaurus, Mycterosuchus, Macrospondylus and Clovesuurdameredeor); enlarged premaxillary foramina lateral to the external nares (similar to Mystriosaurus and Yvridiosuchus); external nares oriented anterodorsally (shared with Plagiophthalmosuchus, the Chinese teleosauroid, I. potamosiamensis, Platysuchus, Mycterosuchus, Aeolodon, Bathysuchus and Sericodon); dorsoventrally deep premaxilla (similar to Mystriosaurus); the anterior and anterolateral premaxillary margins are orientated anteroventrally and extend ventrally (shared with Mystriosaurus, the Chinese teleosauroid, I. potamosiamensis, Platysuchus, Teleosaurus, Mycterosuchus, Bathysuchus and Aeolodon); anterior margin of the supratemporal fossae are noticeably inclined anterolaterally (shared with Mystriosaurus, the Chinese teleosauroid, I. potamosiamensis, Platysuchus, Teleosaurus, Mycterosuchus, Bathysuchus and Aeolodon); frontal width subequal to orbital width (shared with the Chinese teleosauroid, Macrospondylus, Clovesuurdameredeor, Seldsienean, Yvridiosuchus, Deslongchampsina, Proexochokefalos, Mac. hugii and Mac. rex); large, slightly robust teeth (most notably in the posterior dental region) with a pointed apex (most similar to Mystriosaurus).

Remarks—Martin et al. (2019) initially referred PRC-239 to Indosinosuchus potamosiamensis; however, we designate PRC-239 as a separate species, I. kalasinensis, as it differentiates from the holotype (PRC-11) of I. potamosiamensis in several features:

1. Rostrum does not narrow immediately anterior to the orbits in PRC-239, whereas there is a noticeable narrowing of the rostrum in PRC-11;

2. Premaxillary and maxillary neurovascular foramina are nearly 2x larger in PRC-239 than PRC-11, notably in the premaxillae;

3. External nares ‘B’-shaped in anterior view in PRC-239, whereas in PRC-11 they are somewhat‘8-shaped’;

4. Premaxillary length posterior to the external nares is between 50-65% in PRC-239, whereas in PRC-11 the premaxilla length posterior to the external nares is over 67%;

5. Minimum width of the frontal is subequal to orbital width in PRC-239, whereas in PRC-11 the frontal width is noticeably narrower than the orbital width;

6. Dorsal margin of the orbit flush with the skull dorsal surface in PRC-239 (although this may be due to dorsoventral crushing) whereas in PRC-11 the dorsal margins of the orbits are prominently upturned; and

7. Poorly elliptic external mandibular fenestra in PRC-239, whereas in I. potamosiamensis the mandibular fenestra is highly elliptic (anteroposteriorly elongated).

In addition, I. kalasinensis is never recovered as sister taxon to I. potamosiamensis in the phylogenetic analyses conducted below, and I. kalasinensis lacks all autapomorphies seen in I. potamosiamensis.

Macrospondylus Von Meyer, 1831

Type species—Crocodilus bollensis Jäger, 1828. Now referred to as Macrospondylus bollensis (Jäger, 1828), Von Meyer, 1831.

Etymology— ‘Large vertebra.’ Macro is from the Greek makrýs (μάκρος) meaning long, and spondylus is from the Ancient Greek spóndylos (σπόνδυλος) meaning vertebra. Refers to the long, amphicoelous vertebrae.

Diagnosis—same as the only known species (monotypic genus).

Macrospondylus bollensis (Jäger, 1828) Jäger, 1831

(Fig. 14)

Holotype—MMG BwJ 595, a partial postcranial skeleton, including dorsal, sacral and anterior caudal vertebrae, femora, one tibia, one fibula, one pes and disarticulated osteoderms.

Referred material—GPIT-RE-9427; MMG BwJ 565; MMG BwJ 689; NHMUK PV R 324; NHMUK PV R 756; NHMUK PV R 1088; NHMUK PV R 5703; NHMUK PV OR 14436; NHMUK PV OR 14438; NHMW-1848-0031-0001; NHMW-1878-0047-0001; NHMW-1882-0026-4082; PMU R161; SMNS 18672; SMNS 20280; SMNS 20283; SMNS 51555; SMNS 51563; SMNS 51753; SMNS 51957; SMNS 51984; SMNS 53422; SMNS 58876; SMNS 81699; SMNS 10 000 (all representing partial skulls, complete or near-complete skeletons); unnumbered OUMNH partial skull.

Age—early Toarcian, Early Jurassic.

Localities—Baden-Württemberg, Germany; Yorkshire, UK; Sanem, Luxembourg.

Stratigraphic horizons—Posidonia Shale Formation; Whitby Mudstone Formation; Harpoceras serpentinum ammonite Zone (‘schistes bitumineux’).

Scoring sources—the holotype (MMG BwJ 595), as well as a multitude of specimens from Germany, England and Luxembourg, were studied first-hand. Additional photographs were provided by B. Kear (PMU), M. Manabe (NMNSJ), U. Menkveld-Gfeller (NMBE), L. Schöllmann (LWL), A. Sennikov (PIN), W. Simpson (FMNH) and G. Wahlefeld (NMR).

Autapomorphic characters of Ma. bollensis—the proximal region of the humerus is strongly proximodistally elongated and weakly posteriorly hooked; ulna with a well-developed distal curvature.

Emended diagnosis—longirostrine skull; tooth row at a lower level than the quadrate (shared with Plagiophthalmosuchus, Platysuchus, Indosinosuchus, Teleosaurus and Mycterosuchus); no conspicuous ornamentation on the lacrimal (shared with Plagiophthalmosuchus, I. potamosiamensis, Bathysuchus, Aeolodon and Charitomenosuchus); frontal ornamentation extends from the centre to lateral- and anterior-most regions (shared with Plagiophthalmosuchus, the Chinese teleosauroid, Indosinosuchus, Platysuchus, Teleosaurus, Mycterosuchus and Clovesuurdameredeor); external nares oriented dorsally (shared with Plagiophthalmosuchus, Sericodon, Charitomenosuchus, Proexochokefalos, Deslongchampsina, Neosteneosaurus and Machimosaurini); presence of shallow, slightly anteroposteriorly elongated antorbital fenestrae; no anterolateral expansion or inclination of the supratemporal fenestrae (shared with Plagiophthalmosuchus, Clovesuurdameredeor, Charitomenosuchus, Seldsienean, Deslongchampsina, Proexochokefalos, Neosteneosaurus and Machimosaurini); frontal width subequal to orbital width (shared with the Chinese teleosauroid, I. kalasinensis, Clovesuurdameredeor, Seldsienean, Deslongchampsina, Proexochokefalos, Yvridiosuchus, Mac. hugii and Mac. rex); orbit is longitudinal ellipsoid in shape (shared with Plagiophthalmosuchus, the Chinese teleosauroid, Platysuchus, Aeolodon, Charitomenosuchus, Seldsienean, Proexochokefalos, Deslongchampsina and Neosteneosaurus); basisphenoid exposed along the palatal surface, bifurcating the pterygoids (shared with Charitomenosuchus, Deslongchampsina, Proexochokefalos, Neosteneosaurus, Yvridiosuchus and Lemmysuchus); mandibular symphysis over 50% of mandible length (shared with Mycterosuchus, Bathysuchus, Aeolodon, Seldsienean and Charitomenosuchus); anterior maxillary teeth procumbent (shared with I. kalasinensis, Platysuchus, Teleosaurus, Sericodon, Aeolodon and Charitomenosuchus); tuberculum of dorsal rib situated on the medial edge (shared with Platysuchus, Aeolodon and Lemmysuchus); shallow tuberculum on the dorsal ribs (shared with Sericodon, Aeolodon and Charitomenosuchus); forelimb shorter than hindlimb by approximately 22-23% (similar to Platysuchus); tibia shorter than the femur by approximately 25% (similar to Platysuchus); femoral condyles are relatively the same size (shared with Platysuchus, Aeolodon and Lemmysuchus).

Remarks—the holotype of Macrospondylus bollensis (MMG BwJ 595) was one of the first well preserved vertebrate fossils housed in a scientific institution, dating back to 1755 (Von Meyer, 1831: 196). Johann Georg Gmelin, a chemist and pharmacist for the Royal Churfurstliche Naturaliengalerie Dresden, acquired it at the beginning of the 18th century. Von Meyer initially presented the holotype in an 1830 public talk (S. Sachs, 2019, personal communication), and both Dassdorff (1782) and Walch (1796) briefly noted it to be a crocodile skeleton (Von Meyer, 1831); it was then described by Cuvier (1812, 1824) as the iconic “Gavial de Boll” (“Boll gavial”). Jäger (1828) then named the specimen Crocodilus bollensis, and Von Meyer (1831, 1832) defined and described it as a new genus Macrospondylus. The holotype was badly burned in the Zwinger fire of May 1849 (during the Burgerliche revolution) but survived. Due to this damage, it has been suggested that it cannot be referable to other Macrospondylus specimens (M. Wilmsen, 2017, personal communication). However, MMG BwJ 595 displays a combination of postcranial features unique to Macrospondylus (e.g. SMNS 18672; SMNS 51563; SMNS 51753; SMNS 51957):

1. Large, anteroposteriorly elongated and dorsoventrally thin cervical ribs (most posteriorly placed);

2. Shallow tuberculum on dorsal ribs;

3. Ulna with well-developed, pronounced distal curvature that is noticeably larger than the distal part;

4. Anteroposteriorly short anterior iliac process;

5. Femoral condyles of relatively same size; and

6. Dorsal osteoderms with a pronounced keel and subcircular, numerous, separated pits.

Seldsienean gen. nov.

Type species—Steneosaurus megistorhynchus Eudes-Deslongchamps, 1866. Now referred to as Seldsienean megistorhynchus (Eudes-Deslongchamps, 1866) comb. nov. urn:lsid:zoobank.org:act:A5177ED2-1416-4C54-A169-05591DA55D80

Etymology— ‘Rare one’. Seldsīene is Old English for ‘rare’ or ‘seldom seen’ and ‘-an’ is Old English for ‘one’. Refers to the rarity of this taxon compared to other Bathonian teleosauroids.

Diagnosis—same as the only known species (monotypic genus).

Seldsienean megistorhynchus (Eudes-Deslongchamps, 1866) comb. nov.

(Fig. 15)

Holotype—A partial skull and complete mandible initially described by Cuvier (1824), re-described by Eudes-Deslongchamps (1866, 1867), and presumed destroyed in 1944.

Neotype—MMT P28-1 (a partial skull and mandible, as well as isolated vertebrae, fragmented elements, and three osteoderms and teeth) (see Godefroit, Vignaud & Lieger, 1995 for additional information).

Designation of neotype—herein we formally designate MMT P28-1 as the neotype of Se. megistorhynchus. In order to be in full accordance of Article 75 of the ICZN Code, specifically Article 75.3, we make the following statements:

1. This designation is made with the objective of clarifying the taxonomic status of Se. megistorhynchus.

2. Our assertion of the characters that we regard as distinguishing Se. megistorhynchus from other teleosauroid taxa is listed in the species diagnosis below.

3. The neotype can be recognized through both the following diagnosis and Fig. 15.

4. The holotype is presumed destroyed in 1944 during the bombing of Caen.

5. The holotype, in addition to a partial skull, included a complete mandible; E. Eudes-Deslongchamps (1867: 217) stated that the holotype of Se. megistorhynchus consisted of a “Museau très-allonge’, grêle, étroit et aplati dans toute sa longueur” (“Very elongated muzzle, slender, narrow and flattened along its entire length”). As such, the neotype is consistent with what is known of the former name-bearing type.

6. Unfortunately, the locality of the neotype is not known. However, it and the holotype are from the same age (Bathonian) and country (France), and have been referred to as the same species.

7. Se. megistorhynchus is a slender, longirostrine form, which differs from the genera Deslongchampsina (mesorostrine) and Yvridiosuchus (durophagous), which are found in the same stratigraphic horizon and location. In addition, the neotype displays has several distinct features that differ from Deslongchampsina and Yvridiosuchus (e.g. telescopic orbits).

8. The neotype is the property of an internationally recognized scientific institution at the Musée d’art et d’histoire de Toul (MMT), which maintains a research collection with suitable facilities for preserving name-bearing types and is accessible for study.

Referred material— OUMNH J.1414 (near-complete mandible); LPP.T.1 (partial mandible).

Age—Bathonian, Middle Jurassic.

Localities—unspecified location in France; Enslow Bridge, Oxfordshire, UK.

Stratigraphic horizons— ‘Calcaire de Caen’; Cornbrash Formation, Great Oolite Group.

Scoring Sources—the referred specimens (LPP.T.1 and OUMNH J.1415) were studied first-hand. Additional information was taken from Eudes-Deslongchamps (1866, 1867).

Autapomorphic characters of Se. megistorhynchus— small, circular, noticeably spaced ornamentation on prefrontal and lacrimal; extremely interdigitated anterior margin of the palatines; relatively deep, subcircular neurovascular foramina in the posterior region of the dentary, seen in lateral view; deep coronoid groove; dorsal osteoderms with large, irregularly shaped and elongated pits with raised areas in between pits, and a small yet well-developed keel situated in the middle of the osteoderm.

Emended diagnosis—longirostrine skull; rostrum narrows immediately anterior to the orbits (shared with I. potamosiamensis, Teleosaurus, Mycterosuchus, Aeolodon, Bathysuchus and Sericodon); frontal ornamentation restricted to centre (shared with Sericodon, Aeolodon, Charitomenosuchus, Deslongchampsina, Proexochokefalos, Neosteneosaurus and Machimosaurini); no anterolateral expansion or inclination of the supratemporal fenestrae (shared with Plagiophthalmosuchus, Clovesuurdameredeor, Macrospondylus, Charitomenosuchus, Deslongchampsina, Proexochokefalos, Neosteneosaurus and Machimosaurini); antorbital fenestra present; frontal width subequal to orbital width (shared with the Chinese teleosauroid, I. kalasinensis, Clovesuurdameredeor, Macrospondylus, Deslongchampsina, Proexochokefalos, Yvridiosuchus, Mac. hugii and Mac. rex); orbit is longitudinal ellipsoid in shape (shared with Plagiophthalmosuchus, the Chinese teleosauroid, Platysuchus, Aeolodon, Macrospondylus, Charitomenosuchus, Proexochokefalos, Deslongchampsina and Neosteneosaurus); mandibular symphysis over 50% of mandible length (shared with Mycterosuchus, Bathysuchus, Aeolodon, Macrospondylus and Charitomenosuchus); over 30 dentary alveoli per side (shared with Plagiophthalmosuchus, Platysuchus, Bathysuchus, Mycterosuchus and Charitomenosuchus).

Remarks—despite fragmentary material, we consider Seldsienean as a distinct taxon because it is the only longirostrine form present in the Great Oolite Group (UK) during the Bathonian.

Charitomenosuchus gen. nov.

Type species—Steneosaurus leedsi Andrews, 1909. Now referred to as Charitomenosuchus leedsi (Andrews, 1909), comb. nov. urn:lsid:zoobank.org:act:DE54456D-A305-4A5D-8209-A987982B200C

Etymology— ‘Graceful crocodile’. Charitoménos (χαριτωμένος) is Greek for ‘graceful’ (referring to the slender, elegant skull of this taxon) and suchus is the Latinized form of the Greek soukhos (σοῦχος), meaning crocodile.

Diagnosis—same as the only known species (monotypic genus).

Charitomenosuchus leedsi (Andrews, 1909) comb. nov.

(Fig. 16)

Holotype—NHMUK PV R 3320, a nearly complete skull.

Referred material—BRLSI GP1770a-e (a complete skull and mandible); NHMUK PV R 2619 (a complete mandible and additional femora, ilia, ischia, pubes, tibiae, humeri, ulnae, radiae, ribs [cervical, dorsal], partially preserved vertebrae [two cervical, two dorsal, two sacral] and dorsal osteoderms); NHMUK PV R 3806 (a nearly complete skeleton); PETMG R179 (complete skull).

Age—Middle Callovian, Middle Jurassic.

Locality—Peterborough, UK.

Stratigraphic horizon—Peterborough Member, Oxford Clay Formation, Ancholme Group.

Scoring Sources—the holotype (NHMUK PV R 3320) as well as all referred specimens mentioned above were examined first-hand.

Autapomorphic characters of C. leedsi—frontal ornamentation consists of circular, spaced apart pits limited to the centre-most and posterior frontal; strongly interdigitating premaxilla-maxilla suture; narrow mediolateral supratemporal fenestra width (relative to other teleosauroids); supratemporal arch dorsal margin subtly concave in lateral view; neural spine height of anterior thoracic vertebrae is less than centrum height; dorsal osteoderms with large, subcircular well-spaced pits arranged in a semi-parallel pattern; mediolaterally thickened keel on sacral osteoderms.

Emended diagnosis—longirostrine, gracile skull; tooth row and occipital condyle aligned, and quadrate condyle at a lower level (shared with the Chinese teleosauroid, Proexochokefalos, Neosteneosaurus and Machimosaurini); skull width less than 26% of skull length (shared with Plagiophthalmosuchus, Mycterosuchus, Bathysuchus and Aeolodon); no ornamentation on the lacrimal (shared with Plagiophthalmosuchus, I. potamosiamensis, Aeolodon and Macrospondylus); external nares oriented dorsally (shared with Plagiophthalmosuchus, Macrospondylus, Deslongchampsina, Proexochokefalos, Neosteneosaurus and Machimosaurini); premaxilla anterior and anterolateral margins are not subvertical (shared with Plagiophthalmosuchus, Macrospondylus, Andrianavoay, Deslongchampsina, Proexochokefalos, Neosteneosaurus and Machimosaurini); frontal width narrower than orbital width (shared with I. potamosiamensis); orbit is longitudinal ellipsoid in shape (shared with Plagiophthalmosuchus, the Chinese teleosauroid, Platysuchus, Aeolodon, Macrospondylus, Seldsienean, Proexochokefalos, Deslongchampsina and Neosteneosaurus); the anterior process of the jugal is slender, elongated and extends anteriorly (shared with Clovesuurdameredeor, Proexochokefalos, Neosteneosaurus and Machimosaurini); palatine anterior margin terminates level to 15th to 19th maxillary alveoli (shared with I. potamosiamensis and Mac. buffetauti); basisphenoid exposed along the palatal surface, bifurcating the pterygoids (shared with Macrospondylus, Deslongchampsina, Proexochokefalos, Neosteneosaurus, Yvridiosuchus and Lemmysuchus); the mandibular symphysis is over 50% of the mandible length (shared with Bathysuchus, Mycterosuchus, Macrospondylus, Aeolodon and Seldsienean); mandibular symphysis depth is very narrow, approximately 4–4.5% of the mandible length (shared with Mycterosuchus); the P1 is oriented anteriorly whereas the P2 is oriented slightly medially (shared with Proexochokefalos); over 30 dentary alveoli per side (shared with Plagiophthalmosuchus, Platysuchus, Bathysuchus, Mycterosuchus and Seldsienean); slender teeth with weak mediolateral compression (shared with Macrospondylus); neural spine height of mid-cervical vertebrae is approximately equal to centrum height (similar to Aeolodon); the tuberculum and articular facet are situated directly in the dorsal rib (shared with Mycterosuchus); the dorsal rib tuberculum is shallow (shared with Sericodon, Aeolodon and Macrospondylus); proximal humerus strongly posteriorly deflected and hooked (similar to Aeolodon, Macrospondylus and Neosteneosaurus); supraacetabular iliac crest is shallow and poorly pronounced (shared with Neosteneosaurus, Lemmysuchus and Mac. mosae); postacetabular iliac process is fan-shaped (shared with Neosteneosaurus, Lemmysuchus and Mac. mosae); tibia approximately 40–50% shorter than the femur (shared with Mycterosuchus, Neosteneosaurus, Lemmysuchus and Mac. mosae); medial femoral condyle larger than lateral femoral condyle (shared with Mycterosuchus, Neosteneosaurus and Machimosaurus).

Remarks—Both Vignaud (1995) and Mueller-Töwe (2006) considered Mycterosuchus nasutus to be a synonym of Steneosaurus leedsi (= Charitomenosuchus leedsi).

Deslongchampsina Johnson, Young & Brusatte, 2019

Type species—Steneosaurus larteti Eudes-Deslongchamps, 1866. Now referred to as Deslongchampsina larteti (Eudes-Deslongchamps, 1866) Johnson, Young & Brusatte, 2019.

Etymology—Named after Jacques Amand and Eugène Eudes-Deslongchamps, father and son French naturalists who thoroughly described the holotype specimen and additional teleosauroid material.

Diagnosis—same as the only known species (monotypic genus).

Deslongchampsina larteti (Eudes-Deslongchamps, 1866) Johnson, Young & Brusatte, 2019

(Fig. 17)

Holotype—A partial skull associated with a partial symphyseal section of the mandible, pelvis, hindlimb, two vertebrae and dorsal osteoderms. Destroyed in 1944.

Neotype—OUMNH J.29851, a partial skull broken into two pieces. Neotype designation by Johnson, Young & Brusatte (2019).

Age—Bathonian, Middle Jurassic.

Localities—Calvados, France; Enslow Bridge, Oxfordshire, UK.

Stratigraphic horizons— ‘Fuller’s Earth inférieur’; Cornbrash Formation, Great Oolite Group.

Scoring Sources—the neotype (OUMNH J.29851) was studied first-hand.

Autapomorphic characters of D. larteti—feeble constriction of the premaxillae posterior to the external nares, giving the premaxillae a more rounded, ‘globular’ appearance in dorsal and ventral views; posterior processes of the nasals are mediolaterally thin; gradual and well-developed anteroventral sloping of the nasals. See Johnson, Young & Brusatte (2019) for more detail.

Emended diagnosis—mesorostrine snout; frontal ornamentation restricted to the centre (shared with Sericodon, Aeolodon, Seldsienean, Charitomenosuchus, Proexochokefalos, Neosteneosaurus and Machimosaurini); external nares oriented dorsally (shared with Plagiophthalmosuchus, Macrospondylus, Charitomenosuchus, Proexochokefalos, Neosteneosaurus and Machimosaurini); premaxilla anterior and anterolateral margins are not sub-vertical (shared with Plagiophthalmosuchus, Macrospondylus, Andrianavoay, Charitomenosuchus, Proexochokefalos, Neosteneosaurus and Machimosaurini); presence of large, anteroposteriorly elongated antorbital fenestrae, and internal antorbital fenestra over 25% of the length of the orbit (shared with Plagiophthalmosuchus); orbit is longitudinal ellipsoid in shape (shared with Plagiophthalmosuchus, the Chinese teleosauroid, Platysuchus, Aeolodon, Macrospondylus, Charitomenosuchus, Seldsienean, Proexochokefalos and Neosteneosaurus); frontal width subequal with orbital width (shared with the Chinese teleosauroid, Mycterosuchus, Proexochokefalos, Yvridiosuchus, Mac. hugii and Mac. rex); small basioccipital tuberosities (similar to Bathysuchus); palatine anterior margin terminates distal to the 20th maxillary alveoli (shared with Charitomenosuchus, Mycterosuchus and Bathysuchus); mandibular symphysis slightly less than half the mandibular length, between 45 and 50% (shared with Mystriosaurus, I. potamosiamensis and Proexochokefalos); deep, well-developed reception pits throughout the anterior- to mid-maxilla and gradually disappear (similar to Mystriosaurus, Charitomenosuchus and Proexochokefalos); teeth are robust, slightly curved and weakly-compressed, with pointed apices and high relief enamel ridges (similar to Neosteneosaurus).

Proexochokefalos gen. nov.

Type species—Steneosaurus heberti Morel de Glasville, 1876. Now referred to as Proexochokefalos heberti (Morel de Glasville, 1876), comb. nov. urn:lsid:zoobank.org:act:FC885641-54CC-421D-84E7-0341140EB704

Etymology— ‘Big head with big tuberosities’. Proexochi (προεξοχή) is Greek for projection/tuberosity (in an anatomical sense), referring to the large occipital tuberosities that are characteristic of this taxon, and kefálo[s] (κεφάλι) is Greek meaning head.

Diagnosis—mesorostrine snout; lack of a midline cavity (= trench) on the nasals; well-developed occipital tuberosities.

Proexochokefalos heberti (Morel de Glasville, 1876) comb. nov.

(Fig. 18)

Holotype—MNHN.F 1890-13, a complete skull and mandible.

Age—upper Callovian, Middle Jurassic.

Locality—Villers-sur-mer, Calvados, France.

Stratigraphic horizon—Marnes de Dives Formation.

Scoring sources—the holotype (MNHN.F 1890-13) was studied first-hand.

Autapomorphic characters of Pr. heberti—premaxillae dorsoventrally high in lateral view (approximately 38 mm dorsoventral length, from dorsal-most area to tooth row); occipital tuberosities large and well-developed; slightly mediolaterally compressed teeth with pointed apices throughout the dentary series; faint enamel ridges on apical third of teeth; 79-80° posterior curvature of the teeth throughout the entire dental series.

Emended diagnosis—mesorostrine skull; tooth row and occipital condyle aligned, and quadrate condyle at a lower level (shared with the Chinese teleosauroid, Charitomenosuchus, Pr. cf. bouchardi, Neosteneosaurus and Machimosaurini); frontal ornamentation restricted to centre (shared with Sericodon, Aeolodon, Charitomenosuchus, Seldsienean, Deslongchampsina, Neosteneosaurus and Machimosaurini); external nares oriented dorsally (shared with Plagiophthalmosuchus, Macrospondylus, Charitomenosuchus, Deslongchampsina, Neosteneosaurus and Machimosaurini); anterior and anterolateral margins of the supratemporal fenestrae are not sub-vertical (shared with Plagiophthalmosuchus, Macrospondylus, Andrianavoay, Charitomenosuchus, Deslongchampsina, Neosteneosaurus and Machimosaurini); flat nasals with no evidence of a midline concavity (shared with Pr. cf. bouchardi); absence of antorbital fenestrae (shared with Neosteneosaurus and Machimosaurini excluding Yvridiosuchus); supratemporal fenestra length is twice as long as the anterior width (shared with Pr. cf. bouchardi and Neosteneosaurus, and somewhat similar to Machimosaurini); orbit is longitudinal ellipsoid in shape (shared with Plagiophthalmosuchus, the Chinese teleosauroid, Platysuchus, Aeolodon, Macrospondylus, Charitomenosuchus, Seldsienean, Pr. cf. bouchardi, Deslongchampsina and Neosteneosaurus); frontal width sub-equal to orbital width (shared with the Chinese teleosauroid, I. kalasinensis, Macrospondylus, Clovesuurdameredeor, Seldsienean, Deslongchampsina, Yvridiosuchus, Mac. hugii and Mac. rex); anterior process of the jugal is slender and anteriorly elongated (shared with Clovesuurdameredeor, Charitomenosuchus, Neosteneosaurus and Machimosaurini); mandibular symphysis slightly less than half the mandibular length, between 45 and 50% (shared with Mystriosaurus, I. potamosiamensis and Deslongchampsina); deep, well-developed reception pits throughout the anterior- to mid-maxilla and gradually disappear (similar to Mystriosaurus, Charitomenosuchus and Deslongchampsina); shallow Meckelian groove (shared with Neosteneosaurus and Machimosaurini); sharp dorsal curvature of the angular (shared with Neosteneosaurus and Machimosaurini); the P1 is oriented anteriorly whereas the P2 is oriented slightly medially (shared with Proexochokefalos).

Proexochokefalos cf. bouchardi (Sauvage, 1872) comb. nov.

(Fig. 19)

Holotype—A partial specimen initially composed of a skull, mandible and assorted vertebrae (Vignaud, 1995). Currently missing and/or destroyed.

Referred material—Sauvage (1872); Buffetaut & Makinsky (1984); Lepage et al. (2008); SCR010-374 (Schaefer, Püntener & Billon-Bruyat, 2018).

Age—Kimmeridgian, Late Jurassic.

Localities—Villerville, Calvados, France; Courtedoux-sur Combe Ronde, northwestern Switzerland.

Stratigraphic horizons— ‘Calcaire de Caen’; Reuchenette Formation.

Scoring sources—Scores were based on specimen photographs from Lepage et al. (2008) and Schaefer, Püntener & Billon-Bruyat (2018). Additional information was read from Joleaud (1928) and Buffetaut & Makinsky (1984).

Emended diagnosis—mesorostrine skull; tooth row and occipital condyle aligned in the same plane (similar to the Chinese teleosauroid, Charitomenosuchus, Pr. heberti, Neosteneosaurus and Machimosaurini); flat nasals with no evidence of a midline concavity (shared with Pr. heberti); supratemporal fenestrae length is twice as long as width (shared with Pr. heberti and Neosteneosaurus, and somewhat similar to Machimosaurini); frontal width broader than orbital width (shared with Plagiophthalmosuchus, Mystriosaurus, Platysuchus, Teleosaurus, Mycterosuchus, Aeolodon, Bathysuchus, Neosteneosaurus, Mac. buffetauti and Mac. mosae); orbit is ellipsoid in shape (shared with Plagiophthalmosuchus, the Chinese teleosauroid, Platysuchus, Aeolodon, Macrospondylus, Charitomenosuchus, Seldsienean, Deslongchampsina, Pr. heberti and Neosteneosaurus).

Remarks—the mandible of the holotype disappeared, while remnants of the skull material were initially sent to BHN2 (and was considered the lectotype (presumably BHN2 R 59)). However, this museum was closed in 2003 and the current whereabouts of the material is unknown. In addition, Vignaud (1995) considered the remaining vertebrae of the holotype (location also unknown) as the paralectotype, with no formal explanation as to why. In 1892, M. Makinsky discovered the skull figured in Lepage et al. (2008) in the Pictonia baylei ammonite zone (lower Kimmeridgian) near Villerville (Calvados, France). Buffetaut & Makinsky (1984) described it as ‘Steneosaurus’ cf. bouchardi; currently the location of this skull, as with all holotype material, is not known (Y. Lepage, 2018, personal communication). Due to the close phylogenetic placement of this taxon to Proexochokefalos heberti, it is currently considered to be in the same genus.

Steneosaurus Geoffroy Saint-Hilaire, 1825

Type species—Steneosaurus rostromajor Geoffroy Saint-Hilaire, 1825. Type by subsequent designation (see Johnson, Young & Brusatte, 2020).

Etymology— ‘Narrow lizard.’ Steneo is from the Greek sténos (στενός) meaning narrowness (presumably referring to the elongated maxillae), and saurus is Latin meaning lizard.

Diagnosis—nomen dubium, undiagnostic.

Steneosaurus rostromajor Geoffroy Saint-Hilaire, 1825

(Fig. 20)

Lectotype—MNHN.RJN 134, a partial rostrum. Designated by Johnson, Young & Brusatte (2020).

Age—lower Oxfordian, Late Jurassic (Bacheley (1778a, 1778b) and Cuvier (1808, 1812)).

Locality—Vaches Noires, Calvados, France.

Stratigraphic horizon—Marnes de Villiers Formation (hypothesized by Bacheley (1778a, 1778b) and Cuvier (1808, 1812)).

Scoring sources—the lectotype (MNHN.RJN 134c-d) was examined first-hand.

Description—maxillae ornamented with numerous, weakly- to strongly developed grooves; moderately interdigitating premaxilla-maxilla dorsal suture (shared with Mystriosaurus, Proexochokefalos, Andrianavoay, Neosteneosaurus and Machimosaurini); deep, pronounced reception pits throughout the entirety of the maxilla (shared with Andrianavoay, Neosteneosaurus, and Machimosaurini); at least 27 maxillary alveoli; mainly circular, well-spaced maxillary alveoli throughout the entirety of the rostrum; posterior maxillary alveoli slightly smaller than anterior maxillary alveoli (similar to Yvridiosuchus); well-developed, pronounced enamel ridges near the base of the tooth. See Johnson, Young & Brusatte (2020) for more detail.

Remarks—initially, the type species of the genus Steneosaurus (MNHN.RJN 134), Steneosaurus rostromajor Geoffroy Saint-Hilaire, 1825, was composed of a rostrum (MNHN.RJN 134c-d) and orbital region (MNHN.RJN 134a-b); however, the orbital section comes from a metriorhynchid. The validity of this taxon has been called into question due to its fragmentary nature (Eudes-Deslongchamps, 1867) and paraphyletic or polyphyletic nature of Steneosaurus in phylogenetic studies (Mueller-Töwe, 2006; Ősi et al., 2018; Foffa et al., 2019; Johnson, Young & Brusatte, 2019). Currently, only one taxon can hypothetically be referable to S. rostromajor, Neosteneosaurus; however, due to lack of autapomorphic features, uncertainty of teleosauroid ontogenetic and sexual dimorphic stages, a generic concept that has changed multiple times, and poor preservation, S. rostromajor is currently regarded as a nomen dubium (Johnson, Young & Brusatte, 2020).

Andrianavoay gen. nov.

Type species—Steneosaurus baroni Newton, 1893. Now referred to as Andrianavoay baroni (Newton, 1893), comb. nov. urn:lsid:zoobank.org:act:90C7838E-BE28-4615-BB85-BB04B67F1304

Etymology— ‘Noble crocodile’. Andrian’ and voay are Malagasy meaning noble (usually referring to a prince) and crocodile, respectively.

Diagnosis—same as the only known species (monotypic genus).

Andrianavoay baroni (Newton, 1893) comb. nov.

(Fig. 21)

Holotype—NHMUK PV R 1999, a partial skull and mandible with one associated osteoderm.

Age—Lower Oolite, Bathonian, Middle Jurassic, based on association with Mytilus, Modiola, Perna and Trochactmonina shells (Newton, 1893).

Locality—Andranosamonta, northwestern Madagascar.

Stratigraphic horizon—Unknown.

Scoring sources—the holotype (NHMUK PV R 1999) was examined first-hand.

Autapomorphic characters of A. baroni—sparse, small, deep subcircular foramina on the posterior and lateral margins of the external nares; anteroposteriorly thin posterior-most parietal.

Emended diagnosis—maxilla ornamented with numerous, shallow to deep grooves; premaxilla anterior and anterolateral margins are not sub-vertical (shared with Plagiophthalmosuchus, Macrospondylus, Charitomenosuchus, Deslongchampsina, Proexochokefalos, Neosteneosaurus and Machimosaurini); moderately interdigitating premaxilla-maxilla dorsal suture (shared with Mystriosaurus, Proexochokefalos, Neosteneosaurus, S. rostromajor and Machimosaurini); dorsoventrally deep posterior premaxilla (shared with Proexochokefalos); dorsoventrally tall supraoccipital (shared with Plagiophthalmosuchus, Clovesuurdameredeor and Lemmysuchus); deep, pronounced reception pits throughout the entirety of the maxilla (shared with S. rostromajor, Neosteneosaurus and Machimosaurini); osteoderm fragment with large, circular pits that are well separated from one another.

Neosteneosaurus gen. nov.

Type species—Steneosaurus edwardsi Eudes-Deslongchamps, 1868a. Now referred to as Neosteneosaurus edwardsi (Eudes-Deslongchamps, 1868a), comb. nov. urn:lsid:zoobank.org:act:09ADDEA4-AB2B-40A4-AAFF-19819898532F

Etymology— ‘New Steneosaurus’. ‘Neo-’ is from the Greek neos (νέος) meaning ‘new’. Refers to the genus this species previously belonged to, Steneosaurus.

Diagnosis—same as the only known species (monotypic genus).

Neosteneosaurus edwardsi (Eudes-Deslongchamps, 1868a) comb. nov.

(Fig. 22)

Holotype—While Eugène Eudes-Deslongchamps (1867) described and figured MNHN.RJN 118, he did not formally designate it as the holotype, and included other specimens (syntypes) in his original description (Brignon, 2018b).

Lectotype—MNHN.RJN 118, a partial skull (see Brignon, 2018b).

Referred material—GPIT-RE-7286 (complete skeleton); NHMUK PV R 2075 (partial skull, mandible and associated postcrania); NHMUK PV R 2076 (partial mandible and femora, ilia, tibia, ulna, dorsal and sacral osteoderms); NHMUK PV R 2865 (complete skull, assorted vertebrae and isolated teeth); NHMUK PV R 3701 (nearly complete skull and mandible, and partial skeleton); NHMUK PV R 3898 (femur, ilium and ischium); NRM-PZ R.144 (a partial sacral vertebra); NRM-PZ R.2053 (tibia); NRM-PZ R.2074 (femur); OUMNH J.29815 (partial skull); PETMG R175 (complete skeleton); PETMG R178 (nearly complete skeleton); SMF R 123 (complete skull and nearly complete mandible).

Age—Middle Callovian, Middle Jurassic.

Locality—Peterborough, UK.

Stratigraphic horizon—Peterborough Member, Oxford Clay Formation, Ancholme Group.

Scoring sources—the holotype (MNHN.RJN 118), as well as all additional referred specimens, were examined first-hand.

Autapomorphic characters of N. edwardsi—posterior (distal) teeth with sub-pointed apices (are not blunt and rounded but significantly less pointed than in anterior [mesial] and middle teeth); tuberculum and articular facet of the dorsal rib positioned on the lateromedial edge.

Emended diagnosis—mesorostrine snout; tooth row and occipital condyle aligned, and quadrate condyle at a lower level (shared with the Chinese teleosauroid, Charitomenosuchus, Proexochokefalos and Machimosaurini); frontal ornamentation restricted to centre (shared with Sericodon, Aeolodon, Charitomenosuchus, Seldsienean, Deslongchampsina, Proexochokefalos and Machimosaurini); external nares oriented dorsally (shared with Plagiophthalmosuchus, Macrospondylus, Charitomenosuchus, Deslongchampsina, Proexochokefalos, and Machimosaurini); premaxilla anterior and anterolateral margins are not sub-vertical (shared with Plagiophthalmosuchus, Macrospondylus, Andrianavoay, Charitomenosuchus, Deslongchampsina, Proexochokefalos and Machimosaurini); moderately interdigitating premaxilla-maxilla suture, appearing subcircular in shape (shared with Mystriosaurus, Andrianavoay, S. rostromajor, Lemmysuchus and Machimosaurus); absence of antorbital fenestrae (shared with Proexochokefalos and Machimosaurini excluding Yvridiosuchus); supratemporal fenestrae length is twice as long as wide (shared with Proexochokefalos, and somewhat similar to Machimosaurini); the anterior process of the jugal is slender, elongated and extends anteriorly (shared with Clovesuurdameredeor, Proexochokefalos and Machimosaurini); orbit is longitudinal ellipsoid in shape (shared with Plagiophthalmosuchus, the Chinese teleosauroid, Platysuchus, Aeolodon, Macrospondylus, Charitomenosuchus, Seldsienean, Proexochokefalos and Deslongchampsina); frontal width broader than orbital width (shared with Plagiophthalmosuchus, Mystriosaurus, Platysuchus, Teleosaurus, Mycterosuchus, Bathysuchus, Aeolodon, Pr. cf. bouchardi, Mac. buffetauti and Mac. mosae); squamosal projects further posteriorly than occipital condyle (shared with the Chinese teleosauroid and Machimosaurini); shallow Meckelian groove (shared with Proexochokefalos and Machimosaurini); mandibular symphysis between 30 to 45% of the mandibular length; (shared with Machimosaurini); deep, pronounced reception pits throughout the entirety of the maxilla (shared with Andrianavoay, Neosteneosaurus, and Machimosaurini); maxillary teeth not procumbent (shared with Proexochokefalos and Machimosaurini); large, robust, weakly-compressed teeth with a pointed apex and high relief enamel ridges (similar to Deslongchampsina); postacetabular iliac process is fan-shaped (shared with Charitomenosuchus, Lemmysuchus and Mac. mosae); tibia approximately 40-50% shorter than the femur (shared with Mycterosuchus, Charitomenosuchus, Lemmysuchus and Mac. mosae); medial femoral condyle larger than lateral femoral condyle (shared with Mycterosuchus, Charitomenosuchus and Machimosaurus); elongated and pronounced keel across the entirety of the sacral dorsal osteoderms (shared with Lemmysuchus).

TRIBE Machimosaurini (Jouve et al., 2016)

Yvridiosuchus Johnson, Young & Brusatte, 2019

Type species—Steneosaurus boutilieri Eudes-Deslongchamps, 1868b. Now referred to as Yvridiosuchus boutilieri (Eudes-Deslongchamps, 1868b), Johnson, Young & Brusatte, 2019.

Etymology— ‘Hybrid crocodile’. Yvrídio (υβρίδιο) is Ancient Greek for ‘hybrid’ (refers to a unique combination of non-machimosaurin and machimosaurin teleosauroid symplesiomorphies observed in this genus), and suchus is the Latinized form of the Greek soukhos (σοῦχος), meaning crocodile.

Diagnosis—same as the only known species (monotypic genus).

Yvridiosuchus boutilieri (Eudes-Deslongchamps, 1868b) Johnson, Young & Brusatte, 2019

(Fig. 23)

Holotype—A skull fragment, figured by Eudes-Deslongchamps (1867) and presumed lost or destroyed (Vignaud, 1995; Johnson, Young & Brusatte, 2019).

Neotype—OUMNH J.1401, a partial skull. Neotype designation by Johnson, Young & Brusatte (2019).

Referred material—OUMNH J.29850 (nearly complete skull and mandible); OUMNH J.1403 (nearly complete skull); OUMNH J.1404 (partial mandible); OUMNH J.1417 (partial mandible) (see Johnson, Young & Brusatte, 2019).

Age—Bathonian, Middle Jurassic.

Localities—Calvados, France; Enslow Bridge, Oxfordshire, UK.

Stratigraphic horizons— ‘Sommet de la Grande Oolithe, France; Great Oolite Group, UK.

Scoring sources—the neotype (OUMNH J.1401), as well as all referred specimens mentioned above, were studied first-hand.

Autapomorphic characters of Y. boutilieri—heavily ornamented lacrimal, appearing perforated in lateral view; extreme elongation of the anterior jugal, so that it participates in the posterior margin of the antorbital fenestra; orbit subcircular in shape; anterior process of palatine U-shaped; width of retroarticular process is narrower than the glenoid fossa. See Johnson, Young & Brusatte (2019) for more detail.

Emended diagnosis—mesorostrine skull; skull ornamented with numerous conspicuous pits and grooves (differs from that seen in Mycterosuchus and Mystriosaurus); large and numerous neurovascular foramina on the premaxillae, maxillae and dentaries (shared with Mystriosaurus and Machimosaurini); external nares oriented dorsally (shared with Plagiophthalmosuchus, Macrospondylus, Charitomenosuchus, Proexochokefalos, Deslongchampsina, Neosteneosaurus and other members of Machimosaurini); premaxilla anterior and anterolateral margins are not sub-vertical (shared with Plagiophthalmosuchus, Macrospondylus, Andrianavoay, Charitomenosuchus, Deslongchampsina, Proexochokefalos, Neosteneosaurus and other members of Machimosaurini); presence of small, deep antorbital fenestrae; frontal width subequal with orbital width (shared with the Chinese teleosauroid, Mycterosuchus, Proexochokefalos, Deslongchampsina, Mac. hugii, and Mac. rex); squamosal projects further posteriorly than occipital condyle (shared with the Chinese teleosauroid, Neosteneosaurus and other members of Machimosaurini); shallow Meckelian groove (shared with Proexochokefalos, Neosteneosaurus and other members of Machimosaurini); sharp dorsoposterior curvature of the posterior mandibular rami (shared with Proexochokefalos and Lemmysuchus); teeth large and conical with blunt apices (shared with other members of Machimosaurini); teeth not mediolaterally compressed (shared with Bathysuchus and other members of Machimosaurini); carinae heterogeneous with faint denticles (shared with other members of Machimosaurini); teeth with anastomosing pattern on the apical surface (shared with other members of Machimosaurini); maxillary teeth not procumbent (shared with Proexochokefalos, Neosteneosaurus and other members of Machimosaurini).

Remarks—Yvridiosuchus has a long and complicated taxonomic history, including an invalid species name (Crocodilus oxoniensis; following ICZN Code rules), and OUMNH J.1401 (the designated neotype) considered by Eudes-Deslongchamps (1867) as “appartenant à la même espèce” (“belonging to the same species”) to the previously destroyed French holotype (Johnson, Young & Brusatte, 2019). In addition, Teleosaurus (‘Steneosaurus’) brevidens Phillips, 1871, and ‘Steneosaurus’ meretrix Phizackerley, 1951 (the holotype of T. brevidens), are subjective junior synonyms of Yvridiosuchus (see Johnson, Young & Brusatte, 2019 for more information).

Lemmysuchus Johnson et al., 2017

Type species—Steneosaurus obtusidens Andrews, 1909. Now referred to as Lemmysuchus obtusidens (Andrews, 1909) Johnson et al., 2017.

Etymology— ‘Lemmy’s crocodile’. Lemmy refers to Ian Fraser ‘Lemmy’ Kilmister, the deceased founder, lead singer and bassist of the band Motörhead, and suchus is the Latinized form of the Greek soukhos (σοῦχος), meaning crocodile.

Diagnosis—same as the only known species (monotypic genus).

Lemmysuchus obtusidens (Andrews, 1909) Johnson et al., 2017

(Fig. 24)

Holotype—NHMUK PV R 3168, a nearly complete skeleton including the skull, mandible, vertebrae, hindlimbs, and multiple osteoderms.

Referred material—LPP.M.21 (a nearly complete skull and mandible); NOTNH FS3361 (a partial rostrum); PETMG R39 (a rostral-orbital section).

Age—Middle Callovian, Middle Jurassic.

Locality—Peterborough, UK.

Stratigraphic horizon—Peterborough Member, Oxford Clay Formation, Ancholme Group.

Scoring sources—the holotype (NHMUK PV R 3168) and all referred specimens mentioned above were studied first-hand.

Autapomorphic characters of L. obtusidens—the rostrum external surface is strongly convex, in particular the nasals; partial or complete fusion of the internasal suture; nasal midline cavity poorly developed; eight cervical vertebrae; dorsoventrally curved cervical ribs; anterior process of ilium is anteroposteriorly shortened; acetabulum is shallow and poorly developed; shallow supraacetabular crest on the ilium; anterior ischial process reduced; dorsal osteoderms with small-to-large, irregularly shaped pits that radiate from the centre of the keel and are arranged in a starburst pattern (to a certain extent similar to Mac. mosae). See Johnson et al. (2017) for more detail.

Emended diagnosis—mesorostrine skull; external nares oriented dorsally (shared with Plagiophthalmosuchus, Macrospondylus, Deslongchampsina, Proexochokefalos, Neosteneosaurus and other members of Machimosaurini); two parallel lines of large, circular neurovascular foramina on the premaxillae and maxillae, and a clustering of foramina on the lateral surface of the premaxillae (shared with other members of Machimosaurini); premaxilla anterior and anterolateral margins are not sub-vertical (shared with Plagiophthalmosuchus, Macrospondylus, Andrianavoay, Charitomenosuchus, Deslongchampsina, Proexochokefalos, Neosteneosaurus and other members of Machimosaurini); moderately interdigitating premaxilla-maxilla suture, appearing subcircular in shape (shared with Mystriosaurus, Andrianavoay, Neosteneosaurus, S. rostromajor, and Machimosaurus); absence of antorbital fenestrae (shared with Proexochokefalos, Neosteneosaurus and other members of Machimosaurini excluding Yvridiosuchus); parallelogram-shaped supratemporal fenestrae (shared with other members of Machimosaurini); the anterior process of the jugal is slender, elongated and extends anteriorly (shared with Clovesuurdameredeor, Proexochokefalos, Neosteneosaurus and other members of Machimosaurini); squamosal project posteriorly to occipital condyle (shared with Plagiophthalmosuchus, the Chinese teleosauroid, Neosteneosaurus and Yvridiosuchus); supraoccipital dorsoventrally tall (shared with Plagiophthalmosuchus, Clovesuurdameredeor and Andrianavoay); shallow Meckelian groove (shared with Proexochokefalos, Neosteneosaurus and other members of Machimosaurini); retroarticular process subequal to glenoid fossa width (shared with Aeolodon and Mac. buffetauti); teeth large and conical with blunt apices (shared with other members of Machimosaurini); teeth not mediolaterally compressed (shared with Bathysuchus and other members of Machimosaurini); carinae heterogeneous with faint denticles (shared with other members of Machimosaurini); teeth with anastomosing pattern on the apical surface (shared with other members of Machimosaurini); axis lacks diapophyses (shared with Macrospondylus); three sacral vertebrae (shared with Machimosaurus); dorsal ribs with pronounced tuberculum (shared with Mycterosuchus, Neosteneosaurus and Machimosaurus); postacetabular iliac process is fan-shaped (shared with Charitomenosuchus, Neosteneosaurus and Mac. mosae); posteroventral margin of ischial plate sub-squared (shared with Mac. mosae); tibia approximately 40–50% shorter than the femur (shared with Mycterosuchus, Charitomenosuchus, Neosteneosaurus and Mac. mosae); tibial tuberosity angled ventrally (shared with Mac. mosae); elongate and pronounced keel on sacral osteoderms (shared with Neosteneosaurus).

Remarks—the exact location of LPP.M.21, which comes from France, is currently unknown.

GENUS Machimosaurus (Von Meyer, 1837) emend. Von Meyer, 1838

Type species—Machimosaurus hugii Von Meyer, 1837 emend. Von Meyer, 1838

Referred species—Machimosaurus buffetauti Young et al., 2015b; Machimosaurus mosae Sauvage & Liénard, 1879; Machimosaurus rex Fanti et al., 2016.

Etymology— ‘Pugnacious lizard’. Machimo is derived from the Greek machimoi (μάχιμoι), meaning pugnacious (having a combative nature, presumably referring to the robust dentition), and saurus is the Latinized version of sauros (σαυρoς), which is Ancient Greek for lizard.

Age—middle Oxfordian to upper Hauterivian/lower Barremian.

Geographical range—Africa (Ethiopia and Tunisia) and Europe (England, France, Germany, Portugal, Spain and Switzerland).

Generic diagnosis—rostrum wider than high; three alveoli per premaxilla; first premaxillary alveoli strongly oriented anteroventrally; 18–22 alveoli per maxilla; 19–25 alveoli per dentary; maximum supratemporal length is greater than 27% relative to maximum basicranial length; extreme elongation of the supratemporal fenestrae, with the anteroposterior length twice the mediolateral length; medial quadrate hemicondyle considerably smaller than the lateral quadrate hemicondyle; presence of carinae on teeth variable; tall axis neural spine terminating on a plane dorsal to the pre- and postzygapophyses in lateral view; axis neural spine posteriorly expanded in lateral view.

Machimosaurus buffetauti Young et al., 2015b

(Fig. 25)

Holotype—SMNS 91415, a complete skull and mandible (as well as in situ teeth) with associated partial postcranial skeleton including cervical and dorsal vertebrae, one coracoid and multiple osteoderms.

Referred material—DFMMh FV 330 (isolated tooth crown); DFMMh FV 541 (isolated tooth crown); MPV V1600.Bo (anterior region of rostrum and mandible); MPV V1601.Bo (partial rostrum).

Age—Ataxioceras hypselocyclum Sub-Mediterranean ammonite Zone (=Weißer Jura gamma 2), Lower Kimmeridgian, Upper Jurassic.

Localities—Am Hörnle Quarry, Neuffen, Baden-Württemberg, Germany; lower Saxony, Germany; Cricqueboeuf, Normandy, Northern France

Stratigraphic horizons—Lacunosamergel Formation; Langenberg Formation; Calcaires Coquilliers Formation.

Scoring sources—the holotype (SMNS 91415) was examined first-hand, and additional information was gleaned from Young et al. (2014, 2015b).

Autapomorphic characters of Mac. buffetauti—anterolateral frontal projections between nasals and prefrontals; squamosal approximately level with occipital condyle; retroarticular process is slightly longer than wide; low post-symphyseal tooth count of the dentary; dorsal margin of the axis neural arch is strongly concave in lateral view; tuberculum and articular facet of dorsal ribs slightly situated on the medial edge; elongated coracoid glenoid process that extends considerably from the proximal coracoid, and sub-isosceles triangle-shaped in lateral view; anterior margin of the coracoid postglenoid process is slightly concave and terminates approximately in the same frontal plane as the glenoid; posterior margin of the coracoid postglenoid process is strongly concave and terminates approximately in the same frontal plane as the posterior end of the glenoid process; dorsal osteoderms with generally small, irregularly shaped pits arranged in a random pattern, with a shallow keel.

Emended diagnosis—brevirostrine skull; rostrum wider than high; two parallel lines of large, circular neurovascular foramina on the premaxillae and maxillae, and a clustering of foramina on the lateral surface of the premaxillae (shared with Mystriosaurus and members of Machimosaurini); dentary neurovascular foramina form a relatively straight line (shared with Mac. mosae); external nares oriented dorsally (shared with Plagiophthalmosuchus, Macrospondylus, Deslongchampsina, Proexochokefalos, Neosteneosaurus and other members of Machimosaurini); premaxilla anterior and anterolateral margins are not sub-vertical (shared with Plagiophthalmosuchus, Macrospondylus, Andrianavoay, Charitomenosuchus, Deslongchampsina, Proexochokefalos, Neosteneosaurus and other members of Machimosaurini); premaxilla less than 25% of rostral length (shared with Mystriosaurus, the Chinese teleosauroid and Mac. mosae); absence of antorbital fenestrae (shared with Proexochokefalos, Neosteneosaurus, Lemmysuchus and other members of Machimosaurus); parallelogram-shaped supratemporal fenestrae (shared with other members of Machimosaurini); frontal width broader than orbital width (shared with Plagiophthalmosuchus, Mystriosaurus, Platysuchus, Teleosaurus, Mycterosuchus, Bathysuchus, Aeolodon, Pr. cf. bouchardi, Neosteneosaurus and Mac. mosae); circular orbits (shared with Mystriosaurus, Indosinosuchus, Teleosaurus, Mycterosuchus, Clovesuurdameredeor, Lemmysuchus and other members of Machimosaurus); the anterior process of the jugal is slender, elongated and extends anteriorly (shared with Clovesuurdameredeor, Proexochokefalos, Neosteneosaurus and Machimosaurini); quadrates with a single large, circular depression on the dorsal surface close to the hemicondyles; shallow Meckelian groove (shared with Proexochokefalos, Neosteneosaurus and other members of Machimosaurini); retroarticular width is subequal to the glenoid fossa (shared with Aeolodon and Lemmysuchus); 21–28 maxillary alveolar pairs; deep, pronounced reception pits throughout the entirety of the maxilla (shared with Andrianavoay, S. rostromajor, Neosteneosaurus and other members of Machimosaurini); teeth large and conical with blunt apices (shared with other members of Machimosaurini); teeth not mediolaterally compressed (shared with Bathysuchus and other members of Machimosaurini); carinae heterogeneous with faint denticles (shared with other members of Machimosaurini); presence of keeled carinae variable (shared with Mac. hugii and Mac. rex); teeth with anastomosing pattern on the apical surface (shared with other members of Machimosaurini).

Remarks—the correct nominal authority is found in the short taxonomic note in Young et al., 2015b, not Young et al., 2014 (where the new taxon was described).

Machimosaurus mosae Sauvage & Liénard, 1879

(Fig. 26)

Holotype—A skull, destroyed during the First World War. Location and horizon unknown.

Neotype—A partially complete skeleton, labelled as MHNB 1100. Current location unknown.

Referred material—IRSNB (cast of neotype with reconstructed elements added, representing a complete skeleton); Hua (1999); Young et al. (2014).

Age—Either the Aulacostephanus autissiodorensis Sub-Boreal ammonite Zone, uppermost Kimmeridgian, or the Gravesia gigas/Pectinaties elegans Sub-Boreal ammonite Zone, lowermost Tithonian; Late Jurassic (neotype locality).

Neotype locality—Beach near Ambleteuse, Boulonnais, Département du Pas-de-Calais, Nord Pas-de-Calais, France.

Neotype stratigraphic horizon—Argiles de Châtillon Formation.

Scoring sources—Young et al. (2014). Additional information was gleaned from examining the large cast of Mac. mosae in the IRSNB exhibit.

Autapomorphic characters of Mac. mosae—anterior palatal margin terminates at approximately the 11–14th maxillary alveoli; approximately 17–18 alveoli per maxilla; approximately 19–20 alveoli per dentary; coracoid glenoid process very short; anterior edge of the scapula is strongly concave compared to the posterior edge.

Emended diagnosis—brevirostrine skull; conspicuous grooved-ridged ornamentation of maxilla (shared with Mac. hugii and Mac. rex); two parallel lines of large, circular neurovascular foramina on the premaxillae and maxillae, and a clustering of foramina on the lateral surface of the premaxillae (shared with Mystriosaurus and members of Machimosaurini); dentary neurovascular foramina form a relatively straight line (shared with Mac. buffetauti); external nares oriented dorsally (shared with Plagiophthalmosuchus, Macrospondylus, Deslongchampsina, Proexochokefalos, Neosteneosaurus and other members of Machimosaurini); premaxilla anterior and anterolateral margins are not subvertical (shared with Plagiophthalmosuchus, Macrospondylus, Andrianavoay, Charitomenosuchus, Deslongchampsina, Proexochokefalos, Neosteneosaurus and other members of Machimosaurini); premaxilla less than 25% of rostral length (shared with Mystriosaurus, the Chinese teleosauroid and Mac. buffetauti); absence of antorbital fenestrae (shared with Proexochokefalos, Neosteneosaurus, Lemmysuchus and other members of Machimosaurus); parallelogram-shaped supratemporal fenestrae (shared with other members of Machimosaurini); frontal width broader than orbital width (shared with Plagiophthalmosuchus, Mystriosaurus, Platysuchus, Teleosaurus, Mycterosuchus, Bathysuchus, Aeolodon, Pr. cf. bouchardi, Neosteneosaurus and Mac. buffetauti); circular orbits (shared with Mystriosaurus, Indosinosuchus, Teleosaurus, Mycterosuchus, Clovesuurdameredeor, Lemmysuchus and other members of Machimosaurus); shallow Meckelian groove (shared with Proexochokefalos, Neosteneosaurus and other members of Machimosaurini); deep, pronounced reception pits throughout the entirety of the maxilla (shared with Andrianavoay, S. rostromajor, Neosteneosaurus and other members of Machimosaurini); teeth large and conical with blunt apices (shared with other members of Machimosaurini); teeth not mediolaterally compressed (shared with Bathysuchus and other members of Machimosaurini); carinae heterogeneous with faint denticles (shared with other members of Machimosaurini); teeth with anastomosing pattern on the apical surface (shared with other members of Machimosaurini); three sacral vertebrae (shared with Lemmysuchus and potentially other members of Machimosaurus); postacetabular iliac process is fan-shaped (shared with Charitomenosuchus, Neosteneosaurus and Lemmysuchus); posteroventral margin of ischial plate is sub-square (shared with Lemmysuchus); tibial tuberosity angled ventrally (shared with Lemmysuchus); dorsal osteoderms ornamented with small-to-large, irregularly shaped pits that radiate from the centre of the keel and are arranged in a starburst pattern (similar to an extent in Lemmysuchus).

Remarks—the diagnosis of Machimosaurus mosae has until recently been uncertain. Sauvage & Liénard (1879) initially diagnosed this taxon based on an incomplete skull, mandible and postcranial material. However, Krebs (1967) viewed it as a junior synonym of Machimosaurus hugii. Hua (1999) then regarded it as a distinct taxon and proposed a new diagnosis for it, based on a new specimen from the Kimmeridgian of Boulonnais (northwestern France) containing the skull, mandible and partial postcranial material. Pierce, Angielczyk & Rayfield (2009) also considered Mac. mosae to be distinct from Mac. hugii, due to the position of it within their geometric morphometric analysis.

However, Martin & Vincent (2013: 194) criticized Hua (1999) and Pierce, Angielczyk & Rayfield (2009)’s diagnoses, writing ‘most of the content of these diagnoses reveal to be either diagnostic at the genus level or to characterize all Teleosauridae’. Martin & Vincent (2013: 195) then showed that high variation in maxillary and dentary tooth counts among the various Callovian teleosaurids is ‘sufficient difference to discard such an interpretation (the synonymy)’. Martin & Vincent (2013) synonymized Mac. mosae with Mac. hugii, thus re-opening an old debate as to whether Machimosaurus represented a monotypic genus, or if the differences found between Mac. mosae and Mac. hugii were ontogenetic. However, other subsequent studies by Vignaud (1995), Hua (1999) and Young et al. (2014) all considered Mac. mosae to be taxonomically distinct from Mac. hugii. Importantly, Young et al. (2014) outlined five distinct points that strengthen the separation of Mac. mosae from Mac. hugii:

1. The Mac. mosae neotype is equivalent in size to Mac. buffetauti skulls from France and Germany;

2. Lack of juvenile characteristics in any of the French and German Mac. buffetauti skulls;

3. The Mac. mosae neotype exhibits exostoses (the formation of new bone) in the femur, right pubis, and some caudal vertebrae;

4. There is a 3- to 5-million-year gap between the Mac. mosae neotype and the Mac. hugii skulls; and

5. Loss of the prearticulars in Mac. mosae, which are present in Mac. hugii.

There are also certain postcranial features that differentiate Mac. mosae and Mac. hugii, including the shape and size of the coracoid postglenoid and glenoid processes (Young et al., 2014).

Machimosaurus hugii (Von Meyer, 1837) emend. Von Meyer, 1838

(Fig. 27)

Holotype—Von Meyer (1837, 1838) never designated a holotype; when establishing Mac. hugii, he referred to isolated tooth crowns from Solothurn, Switzerland and Kahlenberg, Germany (syntypes).

Lectotype—NMS 8342, an isolated tooth crown. Designation by Krebs (1967).

Referred material—MCNV-CC-4 (isolated tooth crown); MG-25; MG-8730-1 (two rostral pieces); MG-8730-2 (occipital section); MG unnumbered; ML 647; ML 491; ML 657; ML 658; (isolated teeth); Young et al. (2014).

Age—Kimmeridgian, Late Jurassic.

Localities—Kreuzen Quarry at St. Verena, near Solothurn, Canton Solothurn, Switzerland; Guimarota coalmine, Leiria, NW Portugal.

Stratigraphic horizon— ‘Rätschenbank der Schildkrötenschichten’ (“Solothurn Turtle Limestone, Reuchenette Formation”); Guimarota Strata, Alcobaça Formation.

Scoring sources—MG-8730-1, MG-8730-2 and MG unnumbered were examined first-hand, along with multiple teeth (e.g. LMH 16386; LMH 16399; MG 25; NZM-PZ R.2358a-g; SMF R 434a-b). Additional information was taken from Young et al. (2014).

Autapomorphic characters of Mac. hugii—external surfaces of the cranial bones are poorly ornamented, particularly the rostrum and near the orbits; paraoccipital processes greatly enlarged, mediolaterally elongated and with expanded lateral ends, and are larger than the exoccipital-opisthotics; in occipital view, the inter-basioccipital tubera notch is a large inverse ‘U’-shape; dentary interalveolar spacing uniformly narrow.

Emended diagnosis—mesorostrine skull; groove-ridged ornamentation present along the maxilla (shared with Mac. mosae and Mac. rex); circular orbits (shared with Mystriosaurus, Indosinosuchus, Teleosaurus, Mycterosuchus, Clovesuurdameredeor, Lemmysuchus and other members of Machimosaurus); frontal width sub-equal to orbital width (shared with the Chinese teleosauroid, I. kalasinensis, Macrospondylus, Clovesuurdameredeor, Seldsienean, Deslongchampsina, Proexochokefalos, Yvridiosuchus and Mac. rex); parallelogram-shaped supratemporal fenestrae (shared with other members of Machimosaurini); circular orbits (shared with Mystriosaurus, Indosinosuchus, Teleosaurus, Mycterosuchus, Clovesuurdameredeor, Lemmysuchus and other members of Machimosaurus); shallow Meckelian groove (shared with Proexochokefalos, Neosteneosaurus and other members of Machimosaurini); deep, pronounced reception pits throughout the entirety of the maxilla (shared with Andrianavoay, S. rostromajor, Neosteneosaurus and other members of Machimosaurini); teeth large and conical with blunt apices (shared with other members of Machimosaurini); teeth not mediolaterally compressed (shared with Bathysuchus and other members of Machimosaurini); carinae heterogeneous with faint denticles (shared with other members of Machimosaurini); presence of keeled carinae variable (shared with Mac. buffetauti and Mac. rex); teeth with anastomosing pattern on the apical surface (shared with other members of Machimosaurini); pseudodenticles present (shared with Mac. rex); dorsal osteoderm ornamentation composed of small-to-large, well separated, irregularly shaped, randomly arranged pits.

Remarks—In response to Young et al. (2014)’s proposal that the genus Machimosaurus consisted of four distinct species, Martin, Vincent & Falconnet (2015) wrote a brief rebuttal, hypothesising that Machimosaurus was monospecific and Mac. hugii was the only representative of the genus. Foffa, Young & Brusatte (2015) then addressed the rebuttal put forth by Martin, Vincent & Falconnet (2015), noting that the authors did not address the monospecifity of Machimosaurus but rather concentrated on the validity of Mac. buffetauti, suggesting that it is the same as Mac. mosae and that both should be referred to Mac. hugii (as proposed by Martin & Vincent (2013)). Martin, Vincent & Falconnet (2015) claimed that intraspecific variation or post-mortem deformation accounted for the diagnoses put forth by Young et al. (2014); however, while acknowledging that the specimens did undergo some deformation, Foffa, Young & Brusatte (2015) argued that Young et al. (2014)’s diagnoses consisted of accurate morphological traits. In addition, both Young et al. (2014) and Foffa, Young & Brusatte (2015) listed six additional factors that differentiated Machimosaurus species:

1. Stratigraphy;

2. Basioccipital cross-sections;

3. Comparable size and shape of basioccipital tuberosities;

4. Comparable size and lateral expansion of the paraoccipital processes;

5. Dental morphology, as well as enamel traits; and

6. Tooth counts.

Machimosaurus rex Fanti et al., 2016

(Fig. 28)

Holotype—ONM NG 1–25, 80, 81 and 83–87, comprising a fragmented, partially complete skull in association with pieces of the atlas-axis complex, two complete dorsal vertebrae, multiple fragments, and isolated osteoderms and teeth.

Age—late Hauterivian/early Barremian, Early Cretaceous.

Locality—Touil el Mhahir, Tataouine Governorate, Tunisia.

Stratigraphic horizon—Douiret Sand Member, Douiret Formation.

Scoring sources—the holotype was examined first-hand.

Emended diagnosis—mesorostrine skull; conspicuous groove-ridged ornamentation along the maxilla (shared with Mac. mosae and Mac. hugii); frontal width sub-equal to orbital width (shared with the Chinese teleosauroid, I. kalasinensis, Macrospondylus, Clovesuurdameredeor, Seldsienean, Deslongchampsina, Proexochokefalos, Yvridiosuchus and Mac. hugii); circular orbits (shared with Mystriosaurus, Indosinosuchus, Teleosaurus, Mycterosuchus, Clovesuurdameredeor, Lemmysuchus and other members of Machimosaurus); parallelogram-shaped supratemporal fenestrae (shared with other members of Machimosaurini); teeth large and conical with blunt apices (shared with other members of Machimosaurini); teeth not mediolaterally compressed (shared with Bathysuchus and other members of Machimosaurini); carinae heterogeneous with faint denticles (shared with other members of Machimosaurini); presence of keeled carinae variable (shared with Mac. buffetauti and Mac. hugii); teeth with anastomosing pattern on the apical surface (shared with other members of Machimosaurini); pseudodenticles present (shared with Mac. hugii); dorsal osteoderm ornamentation consists of pits with variable size, shape and distribution (similar Lemmysuchus, Mac. buffetauti and Mac. mosae).

Remarks—While Fanti et al. (2016) described this specimen as being Hauterivian in age, the exact age is unclear, due to uncertainty of the geological age of the area, as well as previously disregarded biostratigraphic invertebrate fauna (Dridi & Johnson, 2019; Dridi, 2020). It is also important to note that Mac. rex does not display any autapomorphic characters, given its extremely poor preservation.

Character Descriptions

New characters pertaining to teleosauroids

The 38 new characters introduced here were formulated to describe thalattosuchian, specifically teleosauroid, anatomical variation. These characters are relevant to the interrelationships of teleosauroids, and many highlight previously unexamined morphological divergence between two large subclades within the group (see below). These characters are new and are here used in a cladistic analysis for the first time, and all states (indicated by a number in brackets) are subsequently figured. Character numbering follows the numbering used in the full list of characters for the present analysis (see Supplemental Data SD1). More detailed descriptions and comparisons of all following characters have been provided in the Supplemental Data SD4.

12. Ornamentation on prefrontal in dorsal view: present, with shallow to deep pits and/or grooves (0), or absent (1) (Fig. 29).

This character was inspired by the variety of ornamentation patterns found on the prefrontal of teleosauroid taxa. Ornamentation is either absent (state 1) or comes in the form of shallow to deep pits or shallow to deep, elongated and thin grooves (state 0). State 1 occurs in very few teleosauroids, including the basal teleosauroid Plagiophthalmosuchus (NHMUK PV OR 14792), I. potamosiamensis (PRC-11), Aeolodon (MNHN.F.CNJ 78), Sericodon (Schaefer, Püntener & Billon-Bruyat, 2018) and Bathysuchus (Foffa et al., 2019). The majority of teleosauroids are scored as state 0, including the Chinese teleosauroid (IVPP V 10098), Platysuchus (SMNS 9930), Mycterosuchus (NHMUK PV R 2617), Macrospondylus (GPIT-RE-9427; MMG BwJ 565; SMNS 51555), Charitomenosuchus (NHMUK PV R 3320), Proexochokefalos (MNHN.F 1890-13), and machimosaurins (Yvridiosuchus: OUMNH J.1401; Lemmysuchus: LPP.M.21; Mac. buffetauti: SMNS 91415).

13. Ornamentation on lacrimal in dorsal view: present (0), with shallow to deep pits and/or grooves, or absent (1) (Fig. 29).

As with the above character, the ornamentation displayed on the lacrimal (=lachrymal) differs between taxa. Ornamentation is either absent (state 1) or comes in the form of shallow to deep pits, as well as shallow to deep, elongated and thin grooves (state 0). The majority of teleosauroids (Mystriosaurus: NHMUK PV OR 14781; Platysuchus: SMNS 9930; Mycterosuchus: NHMUK PV R 2617; Proexochokefalos: MNHN.F 1890-13; Lemmysuchus: NHMUK PV R 3168; Mac. buffetauti: SMNS 91415) exhibit state 0, with some form of ornamentation being present. State 1 (lack of ornamentation) occurs in six taxa: I. potamosiamensis (PRC-11), Aeolodon (MNHN.F.CNJ 78), Plagiophthalmosuchus (NHMUK PV OR 14792), Macrospondylus (SMNS 51563), Charitomenosuchus (NHMUK PV R 3320) and Sericodon (Schaefer, Püntener & Billon-Bruyat, 2018). As discussed in ch. 12, lack of ornamentation has previously been attributed to juveniles (Vignaud, 1995); however, this character was scored using adult specimens.

15. Frontal, extension of ornamentation: extends from the centre of the frontal to lateral- and anterior-most regions (0), restricted to centre of the frontal (1) or no ornamentation (2) (Fig. 29).

The frontal of teleosauroids is a single bone that is consistently ornamented throughout the majority of the group, excluding Bathysuchus (unnumbered LPP specimen) and juveniles (e.g. SMNS 10,000). Ornamentation either extends from the centre of the frontal to the anterior- and lateral-most areas (state 0) or is restricted to the midline or centre of the frontal (state 1), with minimal extension.

Plagiophthalmosuchus (NHMUK PV OR 14792), Clovesuurdameredeor (NHMUK PV OR 49126), Macrospondylus (MMG BwJ 565; SMNS 51563) and many basal teleosauroids (e.g. Mystriosaurus: NHMUK PV OR 14781; Platysuchus: SMNS 9930), display state 0. The majority of more derived teleosauroids (e.g. Charitomenosuchus: NHMUK PV R 3320; Proexochokefalos: MNHN.F 1890-13; Lemmysuchus: LPP.M.21; Mac. buffetauti: SMNS 91415), along with Sericodon (SCR010312 in Schaefer, Püntener & Billon-Bruyat (2018)) and Aeolodon (MNHN.F.CNJ 78), share state 1.

It has been suggested that Bathysuchus lacks any frontal ornamentation (Vignaud, 1995), similar to juvenile individuals. However, there may possibly be weak, nearly unnoticeable pits and grooves restricted to the midline of the frontal in this taxon (Fig.), in an LPP unnumbered specimen (Foffa et al., 2019). Due to this uncertainty, this taxon was scored as (?).

43. Premaxilla in dorsal view, the total anteroposterior length relative to total rostrum length is less than 25% (0) or approximately 25% or greater (1) (Fig. 30).

This character focuses on the total anteroposterior premaxillary length in relation to the total anteroposterior rostrum length of a cranium. When defining the rostral length, this refers to the length between the anterior-most premaxillae to the anterior orbital margin.

In the majority of teleosauroids, the premaxillary anteroposterior length is greater than 25% relative to the rostral length (state 1). This condition is observed in the basal teleosauroid Plagiophthalmosuchus (NHMUK PV OR 14792), as well as many longirostrine taxa that are (e.g. Indosinosuchus: PRC239; Mycterosuchus: NHMUK PV R 2617; Macrospondylus: SMNS 18672; Proexochokefalos: MNHN.F 1890-13; Lemmysuchus: NMHUK PV R 3168). Few teleosauroids have a premaxillary anteroposteriorly length that is less than 25% of the rostral length (state 0). This is seen in Mac. buffetauti (SMNS 91415) and Mac. mosae (IRSNB cast; Hua, 1999) as well as Mystriosaurus (NHMUK PV OR 14781) and the Chinese teleosauroid (IVPP V 10098).

56. Premaxilla in dorsal view, the anterior and posterior medial margins of the external nares are formed by two bulbous projections, which are either absent (0) or present (1) (Fig. 31).

In most teleosauroids, the medial margins of the external nares are minimally convex (state 0), causing the external nares to appear D-shaped in dorsal view. This is the condition seen in the basal Plagiophthalmosuchus (NHMUK PV OR 14792) in addition to Mystriosaurus (NHMUK PV R OR 14781), Indosinosuchus (PRC11; PRC-239), the Chinese teleosauroid (IVPP V 10098), Platysuchus (SMNS 9930), Macrospondylus (MMG BwJ 565), Charitomenosuchus (NHMUK PV R 3806), Proexochokefalos (MNHN.F 1890-13), Neosteneosaurus (NHMUK PV R 2865) and Machimosaurini (e.g. Lemmysuchus: NHMUK PV R 3168).

In certain taxa, however, both the anterior and posterior margins are strongly convex, and appear ‘bulging’ in dorsal view. This condition (state 1) is synapomorphic in a unique clade containing Mycterosuchus (NHMUK PV R 2617), Bathysuchus (unnumbered LPP specimen) (Foffa et al., 2019), and possibly Aeolodon (MNHN.F.CNJ 78) (however, specimens of this taxon are dorsoventrally crushed and slightly distorted, so it is difficult to say with certainty if it is present).

58. Premaxilla in dorsal view, the shape of the anteroposterior premaxilla-maxilla contact is triangular (0), subcircular (1) or ‘ragged’ (2) (Fig. 31).

In the basal-most form (Plagiophthalmosuchus: NHMUK PV OR 14792), as well as the Chinese teleosauroid (IVPP V 10098); Indosinosuchus (PRC-11; PRC-239); Platysuchus (SMNS 9930); Aeolodon (MNHN.F.CNJ 78), Mycterosuchus (NHMUK PV R 2617), Bathysuchus (unnumbered LPP specimen) and Macrospondylus (SMNS 51753; SMNS 51984), the contact is triangular with slight or no interdigitating areas (state 0). An intermediate condition (state 1) shows the contact to be anteroposteriorly short and subcircular in shape (more posteromedially horizontally oriented than state 0), with a weak to moderate degree of interdigitating regions, generally close to the midline of the rostrum. This occurs in S. rostromajor (MNHN.RJN 134c-d) as well as Mystriosaurus (NHMUK PV OR 14781), Andrianavoay (NHMUK PV R 1999), Proexochokefalos (MNHN.F 1890-13), Neosteneosaurus (NHMUK PV R 2865) and Machimosaurini (e.g. Lemmysuchus: NHMUK PV R 3168, LPP.M.21). A third condition (state 2) is autapomorphic to Charitomenosuchus (NHMUK PV R 3320, NHMUK PV R 3806): the premaxilla-maxilla suture is anteroposteriorly elongated, sub-rectangular and highly interdigitating, giving it a ‘ragged’-like appearance.

64. Nasals, elongate posterior process that does not (0) or does (1) contact anterior rim of orbit (Fig. 32).

In the majority of teleosauroids (e.g. the Chinese teleosauroid: IVPP V 10098; Platysuchus: SMNS 9930; Mycterosuchus: NHMUK PV R 2617; Lemmysuchus: LPP.M.21), including the basal-most teleosauroid (Plagiophthalmosuchus: NHMUK PV OR 14792), the posterior processes of the nasals reach or extend slightly past the anterior rim of the orbits (state 0). In addition, these processes are positioned medially, slightly mediolaterally thin in the posterior-most area, and do not come into close contact with the medial orbital margin. However, I. potamosiamensis (PRC-11) clearly possesses state 1, in which the nasals have extraordinarily anteroposteriorly elongated posterior processes; these are mediolaterally thin and contacts the medial rim of the orbit (see Martin et al., 2019).

124. Frontal, anteromedial process shape and length relative to nasals: anterior projection of frontal is mediolaterally broad and does not extend far anteriorly past anterior orbital rim into nasals (0) or anterior projection of frontal is mediolaterally thin and extends anteriorly past anterior orbital rim into nasals (1) (Fig. 32).

In the majority of teleosauroids, this process is triangular, thin and anteromedially elongated, usually extending past the anterior orbital margin (state 1). This is seen in taxa such as the basal-most form Plagiophthalmosuchus (NHMUK PV OR 14792) as well as Mystriosaurus (NHMUK PV OR 14781), the Chinese teleosauroid (IVPP V 10098), Indosinosuchus taxa (PRC 11; PRC 239), Platysuchus (SMNS 9930), Mycterosuchus (NHMUK PV R 2617), Aeolodon (MNHN.F.CNJ 78), Macrospondylus (MMG BwJ 565; SMNS 51555), Charitomenosuchus (NHMUK PV R 3320), Deslongchampsina (OUMNH J.29851), Proexochokefalos (MNHN.F 1890-13), Neosteneosaurus (MNHN.RJN 118; PETMG R178) and Machimosaurini (Yvridiosuchus OUMNH J.1401; Lemmysuchus LPP.M.21; Mac. buffetauti SMNS 91415). It is interesting to note that the anteromedial frontal processes in Yvridiosuchus, Indosinosuchus, Charitomenosuchus and Mac. buffetauti are considerably more elongated and mediolaterally thin than in the other aforementioned taxa.

Only one taxon, Clovesuurdameredeor (NHMUK PV OR 49126), expresses state 0, in which the anteromedial frontal process is noticeably mediolaterally broadened (giving it a subcircular appearance in dorsal view) and anteroposteriorly short.

125. Frontal in dorsal view, small anterolateral projections between nasals and prefrontals are absent (0) or present (1) (Fig. 32).

Most teleosauroids do not have these extra frontal projections; instead, the frontal suture is flush with that of the posterior nasal processes (state 0). This condition is clearly seen in the basal teleosauroid Plagiophthalmosuchus (NHMUK PV OR 14792) and the Chinese teleosauroid (IVPP V 10098), Indosinosuchus (PRC-11, PRC-239), Platysuchus (SMNS 9930), Teleosaurus (MNHN AC 8746), Mycterosuchus (NHMUK PV R 2617), Aeolodon (MNHN.F.CNJ 78), Macrospondylus (MMG BwJ 565), Clovesuurdameredeor (NHMUK PV OR 49126), Charitomenosuchus (NHMUK PV R 3320), Deslongchampsina (OUMNH J.29851), Proexochokefalos (MNHN.F 1890-13), Neosteneosaurus (NHMUK PV R 2865), Yvridiosuchus (OUMNH J.1401) and Lemmysuchus (LPP.M.21). The presence of these frontal projections is an apomorphic state, however, in the taxon Mac. buffetauti (Martin & Vincent, 2013; SMNS 91415), in which they are large, mediolaterally broadened and clearly noticeable (state 1).

167. Jugal anterior process is absent (0) or is slender, elongated and extends anteriorly (1) (Fig. 33).

The majority of teleosauroids have a shortened anterior process of the jugal that does not extend past the anterior orbital margin (state 0). This is clearly seen in the basal form Plagiophthalmosuchus (MNHNL. TU515) as well as Mystriosaurus (NHMUK PV OR 14781), the Chinese teleosauroid (IVPP V 10098), Platysuchus (SMNS 9930), Teleosaurus (MNHN AC 8746), Mycterosuchus (NHMUK PV R 2617), Macrospondylus (PMU R161) and Deslongchampsina (OUMNH J.29851).

In certain teleosauroids, the anterior jugal becomes dorsoventrally curved, narrow and anteroposteriorly elongated, and extends substantially past the anterior orbital margin, at times nearly to the posterior region of the antorbital fenestra. This condition (state 1) is present in the taxa Charitomenosuchus (NHMUK PV R 3320), Neosteneosaurus (MNHN.RJN 118; PETMG R178), Proexochokefalos (MNHN.F 1890-130) and members of Machimosaurini (e.g. Yvridiosuchus: OUMNH J.1401).

184. Maxilla in palatal view, shape of anterior maxilla is tapering (subtriangular) (0) or straightened (sub-rectangular) (1) (Fig. 34).

This character focuses on the anterior premaxilla-maxilla contact in palatal view, which is positioned parallel to the fourth premaxillary alveolus. State 1 is a synapomorphic character for members of Teleosauroidea (e.g. the Chinese teleosauroid: IVPP V 10098; Yvridiosuchus: OUMNH J.1401); the contact is horizontal and straight, and sub-rectangular in shape. This character is one key difference from Metriorhynchoidea, in which the contact is subtriangular and anteriorly directed (state 0) (e.g. Metriorhynchus superciliosus: LPP.M.48).

208. Paraoccipital process approximately the same size (0) or substantially larger than the remainder of the exoccipital-opisthotic (1) (Fig. 35).

Generally, the paraoccipital processes (the posterior-most part of the exoccipital-opisthotics) are approximately the same size as the rest of the exoccipital-opisthotic (state 0). This is seen in the basal form Plagiophthalmosuchus (MNHNL TU515) as well as most teleosauroids (e.g. the Chinese teleosauroid: IVPP V 10098; Platysuchus: SMNS 9930; Mycterosuchus: NHMUK PV R 2617; Macrospondylus: SMNS 81699; Charitomenosuchus: NHMUK PV R 3320; Proexochokefalos: MNHN.F 1890-13; Lemmysuchus: NHMUK PV R 3168). In Mac. hugii (MG-8730-2), the paraoccipital processes are noticeably and substantially larger than the remaining exoccipital-opisthotics; this condition (state 1) is autapomorphic for this taxon.

269. Splenials in dorsal view, the excavation of Meckelian groove on the dorsal surface of symphyseal splenials is deep (0) or shallow (1) (Fig. 36).

This character focuses on the excavation of the Meckelian groove (=canal) seen on the dorsal surface of the symphyseal splenials. In more basal and longirostrine teleosauroids (e.g. Mycterosuchus: NHMUK PV R 2617; Macrospondylus: SMNS 53422; Seldsienean: OUMNH J.1414; Charitomenosuchus: NHMUK PV R 3806), the Meckelian groove is anteroposteriorly long relative to jaw length and deeply excavated (state 1). In the taxa Proexochokefalos (MNHN.F 1890-13), Neosteneosaurus (NHMUK PV R 3701) and Machimosaurini (e.g. Lemmysuchus: LPP.M.21), the Meckelian groove is shallow with little to no excavation (state 0).

270. Angular dorsal curvature is gradual (0) or sharp and abrupt (1) (Fig. 37).

In most teleosauroids, the ventral margin of the angular gradually curves posterodorsally (state 0). This condition is seen in Indosinosuchus (PRC-11; PRC-239), Platysuchus (SMNS 9930), Sericodon (SCR010-1184 in Schaefer, Püntener & Billon-Bruyat, 2018), Aeolodon (MNHN.F.CNJ 78), Macrospondylus (SMNS 51753), Charitomenosuchus (NHMUK PV R 3806) and Seldsienean (OUMNH J.1414). Both Plagiophthalmosuchus (MNHNL TU515; NHMUK PV OR 15500) and Mystriosaurus (NHMUK PV OR 14781) also display state 0; however, the anterior-most angular is straight (horizontally directed), and the dorsoposterior curvature is poor and limited to the posterior area.

The curvature of the angular differs in Proexochokefalos (MNHN.F 1890-13), Neosteneosaurus (PETMG R178) and Machimosaurini (Yvridiosuchus: OUMNH J.29850; Lemmysuchus: NHMUK PV R 3168; Machimosaurus: IRSNB cast, SMNS 91415), in which the dorsoposterior curvature is immediate, sharp and abrupt (state 1).

291. Maxilla, reception pits are either absent, shallow throughout, or conspicuous only in the anterior maxilla (0) or pronounced and deep throughout the entirety of the maxilla (1) (Fig. 38).

State 0 includes taxa that have either shallow or absent reception pits on the maxillae; however, it is important to note that reception pits are present in all teleosauroids, so for the purposes of this analysis, state 0 of character 291 focuses purely on taxa with shallow reception pits. These may vary substantially in terms of noticeability; for example, they are present but near invisible in the basal taxon Plagiophthalmosuchus (MNHNL TU515) and are relatively small and shallow, disappearing gradually, in most taxa (e.g. Mystriosaurus: NHMUK PV OR 14781; Platysuchus: SMNS 9930; Mycterosuchus: NHMUK PV R 2617;).

In some taxa, the reception pits are deep and noticeable throughout the near-entirety or entirety of the maxilla, notably so in the anterior and middle regions, although they do become smaller when progressing posteriorly (state 1). This condition is seen in machimosaurins (e.g. Lemmysuchus: NHMUK PV R 3618) as well as Andrianavoay (NHMUK PV R 1999), S. rostromajor (MNHN.RJN 134c-d, to some extent) and large individuals of Neosteneosaurus (PETMG R178).

292. Premaxilla, P1-P2 either does not form a couplet and the interalveolar spacing between P1-P2 and P3-P4 relatively the same size (0) or forms a couplet with the interalveolar spacing between P1-P2 and P3-P4, with P1-P2 being separated by a thin lamina and P3-P4 being well separated (1) (Fig. 39).

The first (P1) and second (P2) premaxillary alveoli are situated anterior to the third (P3) and fourth (P4), which are positioned posterolaterally. The fifth (P5) premaxillary alveolus (present in Bathysuchus, Sericodon and Platysuchus) is positioned dorsally in comparison to the P1 to P4 (Foffa et al., 2019). As such, the interalveolar distance varies between these alveoli. The P1 and P2 can be well separated in a way similar to that between the P3 and P4; the interalveolar spacing is large and noticeable, with the adjacent alveoli at a further distance from one another. This condition (state 0) occurs in Platysuchus (MNHNL TU895), Sericodon (SCR011-406 in Schaefer, Püntener & Billon-Bruyat, 2018), Bathysuchus (DORCM G.05067i) and Mycterosuchus (CAMSM J.1420).

In contrast, in the majority of teleosauroids the P3 and P4 remain separate, but the P1 and P2 are situated closely together and are either separated by a small, thin interalveolar lamina, or appear slightly merged together, thereby creating a P1-P2 ‘couplet’ (state 1). This state is seen in Mystriosaurus (NHMUK PV OR 14781), the Chinese teleosauroid (IVPP V 10098), I. potamosiamensis (PRC-11) and one subclade of teleosauroids (e.g. Macrospondylus SMNS 18672; Charitomenosuchus: NHMUK PV R 3806; Proexochokefalos: MNHN.F 1890-13; Lemmysuchus: NOTNH FS3361). Note that this character is not applicable for taxa that have fewer than four premaxillary alveoli (Machimosaurus).

293. Premaxilla, P3-P4 couplet is present (0) or absent (1) (Fig. 39).

In most teleosauroids, the interalveolar spacing is generally noticeable and well-developed between the P3 and the P4, but it is usually small (possibly due to both alveoli being quite large); the alveoli are therefore closely spaced together, forming a couplet (state 0). This is present in most teleosauroids (e.g. Mystriosaurus: NHMUK PV OR 14781; Platysuchus: MNHNL TU895; Mycterosuchus: CAMSM J.1420; Macrospondylus SMNS 81699; Proexochokefalos: MNHN.F 1890-13; Lemmysuchus: NOTNH FS3361). State 1 is found in both Bathysuchus (NHMUK PV OR 43086, DORCM G.05067i) and the Chinese teleosauroid (IVPP V 10098), in which the P3-P4 are widely spaced apart from one another, and therefore do not form a couplet. Note that this character is not applicable for taxa that have fewer than four premaxillary alveoli (Machimosaurus).

294. Premaxilla in palatal view, both P1 and P2 are oriented anteriorly (0), P1 is oriented anteriorly and P2 slightly medially (1), or both P1 and P2 are oriented laterally (2) (Fig. 39).

In many teleosauroids, both the P1 and P2 are oriented anteriorly (state 0). This occurs in Mystriosaurus (NHMUK PV OR 14781), I. potamosiamensis (PRC11), Platysuchus (MNHNL TU895), Macrospondylus (SMNS 18672), Deslongchampsina (OUMNH J.29851), Neosteneosaurus (NHMUK PV R 28650), Yvridiosuchus (OUMNH J.1401) and Lemmysuchus (NOTNH FS3361). In a second condition (state 1), the P1 is oriented anteriorly, but the P2 is oriented slightly medially. This is seen in Charitomenosuchus (NHMUK PV R 3806) and Proexochokefalos (MNHN.F 1890-13). A third condition (state 2), which occurs in Bathysuchus (Foffa et al., 2019), Sericodon (SCR011-406 in Schaefer, Püntener & Billon-Bruyat, 2018) and Mycterosuchus (CAMSM J.1420), is that the P1 and P2 are both strongly oriented laterally, appearing almost horizontally placed. Note that this character is not applicable for taxa that have fewer than four premaxillary alveoli (Machimosaurus).

295. Premaxilla, both P1 and P2 do not form a couplet and are either not oriented on the anterior margin of the premaxilla (0) or are oriented on the anterior margin of the premaxilla (1) (Fig. 39).

In certain teleosauroids, if the P1-P2 alveolar complex does not form a couplet, these two alveoli are positioned either on or slightly ventral to the anterior margin of the premaxilla. In Platysuchus (SMNS 9930), the P1 and P2 do not form such a couplet and both alveoli are not oriented on the anterior margin of the premaxilla (state 0). However, in the genera Bathysuchus (DORCM G.05067i, unnumbered LPP specimen), Sericodon (SCR011-406 in Schaefer, Püntener & Billon-Bruyat, 2018) and Mycterosuchus (CAMSM J.1420), the P1 and P2 do not form a couplet but are noticeably oriented on the anterior margin of the premaxilla (state 1). Note that this character is not applicable for taxa that have fewer than four premaxillary alveoli (Machimosaurus).

296. Premaxilla with no strong lateral expansion (0) or strong lateral expansion so that P3 and P4 are aligned on the lateral plane of the external margin, more so than P2 (1) (Fig. 39).

In most teleosauroids, the P3 and P4 are positioned posteriorly to the P1 and P2 and are aligned on a vertical plane of the lateral margin, whereas the P1 and P2 are aligned more laterally,, due to little or no lateral expansion of the premaxillae (state 0). This condition can be clearly seen in Plagiophthalmosuchus (NHMUK PV OR 14792), more basal teleosauroids (e.g. Mystriosaurus: NHMUK PV OR 14781; Platysuchus: MNHNL TU895), and in more derived teleosauroids (e.g. Charitomenosuchus: NHMUK PV R 3806; Proexochokefalos: MNHN.F 1890-13; Lemmysuchus: LPP.M.21). In select taxa, the premaxillae are laterally expanded, with the P3 and P4 aligned on a different plane (state 1). This occurs in Bathysuchus (DORCM G.05067i; unnumbered LPP specimen) and Sericodon (Schaefer, Püntener & Billon-Bruyat, 2018).

297. Premaxilla, very small first premaxillary alveolus with the second premaxillary alveolus being much larger (0) or the first and second premaxillary alveoli are relatively the same size (1) (Fig. 39).

In most teleosauroids, the size of the P1 and P2 are relatively the same, with both being slightly smaller than the P3 and P4 (which is often the largest, as it houses the large fourth premaxillary tooth) (state 1). This condition is observed in I. potamosiamensis (PRC-11), Mycterosuchus (CAMSM J.1420), Bathysuchus (DORCM G.05067i), Deslongchampsina (OUMNH J.29851), Charitomenosuchus (NHMUK PV R 3806), Proexochokefalos (MNHN.F 1890-13), Neosteneosaurus (NHMUK PV R 2865), Yvridiosuchus (OUMNH J.1401) and Lemmysuchus (LPP.M.21). In certain teleosauroids, the P1 is considerably smaller than the P2, with the P1 being 25% or less the size of the P2 (state 0). This condition is observed in the Chinese teleosauroid (IVPP V 10098) and Macrospondylus (SMNS 81699).

339. Dentition, carinae on the apical third of a tooth are present and well pronounced (0) or absent/weakly pronounced (1) (Fig. 40).

All known teleosauroids possess carinae (excluding the Chinese teleosauroid IVPP V 10098, Andrianavoay NHMUK PV R 1999, Clovesuurdameredeor NHMUK PV OR 49126 and P. cf. bouchardi (Lepage et al., 2008), as none have any teeth preserved); in addition, most teleosauroids have carinae that extend the entire apicobasal length of the tooth, (state 0). These is seen in the basal form Plagiophthalmosuchus (MNHNL TU515) and Mystriosaurus (NHMUK PV OR 14781), I. kalasinensis (PRC-239), Mycterosuchus (NHMUK PV R 2617), Aeolodon (MNHN.F.CNJ 78) Charitomenosuchus (NHMUK PV R 3806), Proexochokefalos (MNHN.F 1890-13) Seldsienean (OUMNH J.1414), Neosteneosaurus (PETMG R178), Lemmysuchus (NHMUK PV R 3168) and Mac. hugii (MG8730-1). However, two taxa (Bathysuchus: DORCM G.05067iv; Sericodon: TCH005-151 in Schaefer, Püntener & Billon-Bruyat, 2018) have carinae that only extend two-thirds the apicobasal length of the tooth, from the base to the apex and are absent at the apex (state 1).

340. Dentition, enamel ridges on the apical third of a tooth are absent (0) or present (1) (Fig. 40).

In teleosauroids, the enamel ridges are either faint and/or difficult to see (e.g. Plagiophthalmosuchus: MNHNL TU515), or noticeable and well-developed (e.g. Mycterosuchus: NHMUK PV R 2617). Enamel ridges are present on the entirety of the crown, including the apex (state 1) in the basal-most form Plagiophthalmosuchus (MNHNL TU515), along with most teleosauroids (e.g. Mystriosaurus: NHMUK PV OR 14781; Mycterosuchus: NHMUK PV R 2617; Bathysuchus: DORCM G.05067iv; 53422; Charitomenosuchus: NHMUK PV R 3806; Seldsienean: OUMNH J.1414; Deslongchampsina: OUMNH J.29851; machimosaurins: NHMUK PV R 3168; NHMW 1846.III.208). Only in one confirmed taxon, Sericodon (TCH005-151 in Schaefer, Püntener & Billon-Bruyat (2018)), are the enamel ridges absent from the apex (state 0).

394. Cervical ribs in lateral view, the anteroposterior ridge of large, more posteriorly placed cervical ribs is straight (0) or dorsoventrally curved (1) (Fig. 41).

Most teleosauroids that can be scored for this character exhibit T-shaped (in dorsal view) cervical ribs where the anteroposterior ridge is horizontal or straightened (state 0)(Platysuchus : SMNS 9930); Mycterosuchus: NHMUK PV R 2617; Charitomenosuchus: NHMUK PV R 3806. However, in Lemmysuchus (NHMUK PV R 3168), the largest, most posteriorly placed cervical ribs have a distinct dorsomedial curvature along the anteroposterior ridge, appearing slightly concave in lateral view (state 1).

395. Dorsal ribs, the positioning of both the tuberculum and articular facet is on the medial edge (0), directly in the middle (1), or on the lateromedial edge (2) (Fig. 42).

In most teleosauroids with preserved dorsal ribs, both the tuberculum and articular facet are positioned on the medial edge of the rib (state 0). This is observed in Platysuchus (SMNS 9930), Macrospondylus (SMNS 51753, SMNS 18672), Aeolodon (MNHN.F.CNJ 78) and Lemmysuchus (NHMUK PV R 3168). In two taxa (Mycterosuchus: NHMUK PV R 2617; Charitomenosuchus: NHMUK PV R 3806), the tuberculum and articular facets have shifted laterally and are placed directly in the middle of the rib (state 1). In Neosteneosaurus (NHMUK PV R 3701, PETMG R178), the tuberculum and articular facets have shifted even further laterally so that they are positioned on the lateromedial edge of the rib (state 2).

396. Dorsal ribs in lateral view, the tuberculum is pronounced (0) or weak (1) (Fig. 42).

In Mycterosuchus (NHMUK PV R 2617), Neosteneosaurus (PETMG R178), Lemmysuchus (NHMUK PV R 3168) and Mac. buffetauti (SMNS 91415), the tuberculum is well-developed and pronounced, as large as the capitulum and anteroposteriorly elongated, giving it an oval shape (state 0). In certain taxa (Sericodon: Schaefer, Püntener & Billon-Bruyat, 2018; Aeolodon: MNHN.F.CNJ 78; Macrospondylus: SMNS 51753; Charitomenosuchus: NHMUK PV R 3806), the tuberculum is reduced, small and circular in shape (state 1).

398. Second sacral vertebrae, the anterior margin of the posterior area of the second sacral vertebra has either a small, non-expanding flange (0) or a large, expanded and projecting flange (1) (Fig. 43).

In crocodylomorphs, the posterior area of the second sacral vertebra has an anterior margin that is both anteroposteriorly and dorsoventrally expanded into a projection or ‘flange’ of bone, which allows for a secure attachment to the ilium, thus influencing body movement. This ‘flange’ is either small and non-expanding (state 0), or noticeably expanded and anteroposteriorly protruding (state 1). All scored teleosauroids exhibit state 1, as there is always an expanded flange present on the anterior margin; however, the size and development differ. In the taxa Mycterosuchus (NHMUK PV R 2617), Charitomenosuchus (NHMUK PV R 3806), Lemmysuchus (NHMUK PV R 3168) and Mac. mosae (Hua, 1999; Young et al., 2014), the flange is considerably larger, more pronounced and well-developed. In Macrospondylus (MMG BwJ 595) and Neosteneosaurus (NHMUK PV R 3701) the flange is still present, but it is much smaller and less obvious.

417. Radius and ulna, the same length (0) or the ulna is longer (1) (Fig. 44).

In the majority of teleosauroids, the radius and ulna are approximately the same size (Andrews, 1913), with the ulna being marginally longer (state 0); this is seen in taxa such as Platysuchus (SMNS 9930), Aeolodon (MNHN.F.CNJ 78), Macrospondylus (SMNS 51563, SMNS 53422), Charitomenosuchus (NHMUK PV R 3608), Neosteneosaurus (PETMG R178) and Lemmysuchus (NHMUK PV R 3168). However, in the genus Mycterosuchus (NHMUK PV R 2617) the ulna is roughly 18% longer than the radius (state 1), which is unusual.

430. Pubis, the shape of distal rim of distal pubic blade is straight and square-like (0) or curved and rounded (1) (Fig. 45).

In most scored teleosauroids, the ventral (distal) margin of the pubic blade is anteriorly curved and rounded in lateral view (state 1). This is the case in Charitomenosuchus (NHMUK PV R 3806), Macrospondylus (SMNS 51957), Neosteneosaurus (PETMG R178), Lemmysuchus (NHMUK PV R 3168) and Mac. mosae (Hua, 1999; Young et al., 2014). However, in two taxa the distal rim of the pubic blade is straightened and relatively square-like (state 0): Mycterosuchus (NHMUK PV R 2617) and Platysuchus (SMNS 9930).

431. Pubis, the pubic shaft is shorter (0) or longer (1) than the pubic blade (Fig. 45).

In most teleosauroid taxa, the pubic shaft is either approximately the same length or slightly anteroposteriorly shorter than the pubic blade (state 0). This is the condition seen in six scored teleosauroids: Macrospondylus (SMNS 51957), Charitomenosuchus (NHMUK PV R 3806), Lemmysuchus (NHMUK PV R 3168), Mac. mosae (Hua, 1999), Platysuchus (SMNS 9930) and Sericodon (SCR010-312 in Schaefer, Püntener & Billon-Bruyat, 2018). However, the pubic shaft is significantly longer (over 50%) than the pubic blade (state 1) in one taxon (Mycterosuchus: NHMUK PV R 2617) and represents an apomorphic trait of this genus.

434. Ilium, the anterior iliac process is long and slender (0), or short and robust (1) (Fig. 46).

In most teleosauroids, the anterior iliac process is anteroposteriorly elongated, mediolaterally slender, and straight with little to no curvature (state 0). This is seen in Platysuchus (SMNS 9930), Teleosaurus (NHMUK PV R 1782a), Sericodon (SCR010-312 in Schaefer, Püntener & Billon-Bruyat, 2018), Aeolodon (MNHN.F.CNJ 78), Macrospondylus (MMG BwJ 565), Charitomenosuchus (NHMUK PV R 3806; Andrews, 1913) and Neosteneosaurus (PETMG R178). In contrast, state 1 describes the anterior process as anteroposteriorly shortened, robust and chunky in appearance, with a slight lateral curvature. This morphology is present in the machimosaurins Lemmysuchus (NHMUK PV R 3168) and Mac. mosae (Hua, 1999; Young et al., 2014), as well as the basal metriorhynchoid Pelagosaurus (MNHN.RJN 463) and members of Metriorhynchidae (e.g. Tyrannoneustes lythrodectikos Young et al., 2013; Cricosaurus lithographicus; Cricosaurus araucanensis (Herrera, Fernández & Gasparini, 2013); Fraas, 1902; Andrews, 1913).

438. Supraacetabular iliac crest is pronounced (0) or shallow and poorly developed (1) in medial view (Fig. 46).

In non-machimosaurins (e.g. Plagiophthalmosuchus: NHMUK PV OR 14792; Platysuchus: SMNS 9930; Charitomenosuchus: NHMUK PV R 3806; Neosteneosaurus: NHMUK PV R 3701, PETMG R178) the supraacetabular crest is enlarged and pronounced, jutting out laterally and slightly overhanging the acetabulum (state 0). In state 1, the supraacetabular crest is poorly developed, with either shallow or no outward projection. This is the case in the machimosaurins Lemmysuchus (NHMUK PV R 3168; Johnson et al., 2017) and Mac. mosae (Hua, 1999).

449. Ischium, the posteroventral margin of ischial blade is triangular (0) or sub-square (1) (Fig. 47).

In most teleosauroids, the ischial blade is gracile, mediolaterally thin and anteroposteriorly elongated, with the posteroventral margin having a triangular-like shape (state 0). This morphology is present in Platysuchus (SMNS 9930), Teleosaurus (NHMUK PV R 1638), Mycterosuchus (CAMSM J.1420), Macrospondylus (SMNS 51957), Charitomenosuchus (NHMUK PV R 3806) and Neosteneosaurus (NHMUK PV R 3701, PETMG R178). A second condition (state 1) is that the posteroventral margin is noticeably anteroposteriorly shortened and dorsoventrally broad, giving it a sub-square shape. This state is unique to machimosaurins (Lemmysuchus: NHMUK PV R 3168; Mac. mosae: ISRNB cast; Hua, 1999; Young et al., 2014).

456. Femur in dorsal view, the anteromedial tuber is present and small (0), or the largest of the proximal tubera (1) (Fig. 48).

In most teleosauroids, the posteromedial tuber is the largest of the three femoral tubera, and the anteromedial tuber is present but relatively small (state 0). This is the condition seen in Platysuchus (SMNS 9930), Sericodon (SCR010-312 in Schaefer, Püntener & Billon-Bruyat, 2018), Aeolodon (MNHN.F.CNJ 78), Macrospondylus (SMNS 18672), Charitomenosuchus (NHMUK PV R 3806), Neosteneosaurus (PETMG R178) and machimosaurins (Lemmysuchus: NHMUK PV R 3168; Machimosaurus: Hua, 1999) The genus Mycterosuchus (NHMUK PV R 2617), however, has an anteromedial tuber that is noticeably well pronounced and well-developed, and it is the largest of all proximal tubera (state 1).

459. Femur, the distal medial and lateral condyles are the same size (0), or the medial condyle is larger than the lateral condyle (1) (Fig. 48).

In most teleosauroids, the medial and lateral condyles of the femur are approximately the same size (state 0). This condition is seen in the basal form Plagiophthalmosuchus (NHMUK PV OR 14792), as well as Platysuchus (SMNS 9930), Aeolodon (MNHN.F.CNJ 78), Macrospondylus (SMNS 51555) and Lemmysuchus (NHMUK PV R 3168). In certain teleosauroid genera, however, the femoral medial condyle is noticeably larger than the femoral lateral condyle (state 1). This is the case in Mycterosuchus (NHMUK PV R 2617) and Neosteneosaurus (NHMUK PV R 3701, PETMG R178).

464. Tibia in lateral view, the angle of tibial tuberosity is horizontal (0) or ventral (1) (Fig. 49).

In most scored teleosauroids, the tibial tuberosity is horizontally placed in lateral view (state 0). This is seen in the basal form Plagiophthalmosuchus (NHMUK PV OR 14792) as well as Platysuchus (SMNS 9930), Mycterosuchus (NHMUK PV R 2617), Aeolodon (MNHN.F.CNJ 78), Macrospondylus (SMNS 51984), Charitomenosuchus (NHMUK PV R 3806) and Neosteneosaurus (NHMUK PV R 3701, PETMG R178). In select teleosauroids, the angle of the tibial tuberosity is strongly ventrally displaced. This condition (state 1) is seen in machimosaurins (Lemmysuchus: NHMUK PV R 3168; Machimosaurus: IRSNB cast; Hua, 1999).

466. Calcaneum, the calcaneum tuber is the same size (0) or larger (1) than the astragalus (Fig. 50).

Both the calcaneum and astragalus are approximately the same shapes in all scored teleosauroids; both tarsal bones are also relatively the same size as one another (state 0), with the calcaneum being marginally larger. This condition is observed in Platysuchus (SMNS 9930), Macrospondylus (MMG BwJ 565, SMNS 51984), Charitomenosuchus (NHMUK PV R 3806), Neosteneosaurus (PETMG R178) and Lemmysuchus (NHMUK PV R 3168). However, in Mycterosuchus (NHMUK PV R 2617) the enlarged calcaneum tuber is noticeably larger than the astragalus (state 1), by approximately 25%. This condition is currently autapomorphic for this genus.

489. Sacral dorsal armour (osteoderms), the dorsal keel is elongated and shallow (0) or elongated and pronounced (1) (Fig. 51).

In certain teleosauroids, the longitudinal ridge (or keel) on the dorsal osteoderms is anteroposteriorly elongated but shallow (state 0). This condition is seen in Plagiophthalmosuchus (NHMUK PV OR 14792), Platysuchus (SMNS 9930), Teleosaurus (NHMUK PV R 4207, NHMUK PV OR 32584), Aeolodon (NHMUK PV R 1086, MNHN.F.CNJ 78), Macrospondylus (SMNS 51563) and Charitomenosuchus (NHMUK PV R 3806). In more derived teleosauroids, the keel of the sacral osteoderms is elongated, well-developed and thickened (state 1). State 1 is well exemplified in large specimens of Neosteneosaurus (PETMG R178) as well as the machimosaurin Lemmysuchus (NHMUK PV R 3168).

Previous characters pertaining to teleosauroids

In addition to the 38 new characters described above, several original characters from the 2016 H+Y dataset are key in differentiating between various teleosauroid taxa. In particular, 19 characters are anatomically distinct, variant and important in teleosauroids and are described in detail as follows (as mentioned previously, all following characters are thoroughly described in SD4):

10. Rostrum narrows markedly in dorsal view immediately in front of the orbits (0), or there is no narrowing (1) (Fig. 52).

In most teleosauroids, the posterior portion of the rostrum will either narrow slightly mediolaterally or not narrow at all, instead becoming flush with the anterior rim of the orbit (state 1). This is seen in Plagiophthalmosuchus (NHMUK PV OR 14792), Mystriosaurus (NHMUK PV OR 14781), the Chinese teleosauroid (IVPP V 10098), Platysuchus (SMNS 9930), and a particular subclade of teleosauroids (e.g. Macrospondylus MMG BwJ 565; Charitomenosuchus: NHMUK PV R 3806; Proexochokefalos: MNHN.F 1890-13; Mac. buffetauti SMNS 91415). In certain teleosauroids, however, there is a distinct and pronounced narrowing, or mediolateral compression, of the rostrum immediately anterior to the orbits, causing the dorsal margins of the orbits to become upturned (state 0). This condition is in Mycterosuchus (NHMUK PV R 2617), Aeolodon (MNHN.F.CNJ 78), I. potamosiamensis (PRC-11), Teleosaurus (MNHN AC 8746), Sericodon (Schaefer, Püntener & Billon-Bruyat, 2018), and Bathysuchus (Foffa et al., 2019).

27. Neurovascular foramina of the premaxillae/maxillae, represented by a single line of small sub-circular openings (0), or two lines (one dorsal, one ventral) of large, circular openings (1) (Fig. 53).

On the lateral premaxillae and maxillae, teleosauroids possess numerous neurovascular foramina. These openings are possibly involved with multiple mechanoreceptory function such as prey detection, tactile discrimination or disruption in the surrounding water (Soares, 2002; Leitch & Catania, 2012). In most teleosauroids, the neurovascular foramina are small and subcircular in shape on both the premaxilla and maxilla, and are generally consistent in size and number. On the premaxilla, these foramina are restricted to the anteroventral and lateroventral margins of the external nares. On the ventrolateral surface of the maxilla, dorsal to the tooth row, they form a single line and are relatively well spaced. This condition (state 0) is seen in taxa such as the basal-most teleosauroid Plagiophthalmosuchus (NHMUK PV OR 14792) and Platysuchus (SMNS 9930), Mycterosuchus (NHMUK PV R 2617), Macrospondylus (PMU R161), and Neosteneosaurus (NHMUK PV 2865). Deslongchampsina (OUMNH J. 29851) also has restricted foramina on the premaxilla as well as a single line on the maxilla; however, the foramina are larger than those seen in other taxa with state 0, and are slightly anteroposteriorly elongated on the maxilla (most notably at the anterior and middle areas of the rostrum).

State 1 is seen in the genus Mystriosaurus (NHMUK PV R 14781) along with members of Machimosaurini (Yvridiosuchus: OUMNH J.1401, OUMNH J.29850; Lemmysuchus: NHMUK PV R 3168; Mac. buffetauti: SMNS 91415; Mac. mosae: Young et al., 2014): these taxa display large, deep, numerous, sub-circular neurovascular foramina (although the foramina in Mystriosaurus are smaller than in machimosaurins). The premaxillary openings are generally circular in shape, located around the ventral, lateral and anteroventral margins of the external nares and cluster together (especially around the external nares’ lateral margins). On the maxilla, the foramina are more anteroposteriorly elongated and situated in two parallel lines, one dorsal to the tooth row with an additional line above it (state 1). The foramina are closely spaced together at the anterior part of the maxilla, but they gradually become more distanced from one another further posteriorly. In addition, it is interesting to note that the premaxillary foramina are exceptionally large in Yvridiosuchus (OUMNH J.29850) as well as only around the anteroventral margin of the external nares in I. kalasinensis (PRC-239).

34. External nares oriented anteriorly or anterodorsally (0), or dorsally (1) (Fig. 54).

In a certain group of predominately Laurasian teleosauroids, the external nares face either anteriorly or anterodorsally (state 0). This condition occurs in Mystriosaurus (NHMUK PV OR 14781), the Chinese teleosauroid (IVPP V 1009), Mycterosuchus (NHMUK PV R 2617), Teleosaurus (Eudes-Deslongchamps, 1867), Platysuchus (SMNS 9930), Aeolodon (MNHN.F.CNJ 78), Sericodon (SCR011-406 in Schaefer, Püntener & Billon-Bruyat, 2018) and Bathysuchus (unnumbered LPP specimen). In predominately Sub-Boreal/Gondwanan teleosauroids, the external nares are oriented dorsally (state 1). This is seen in Macrospondylus (PMU R161), Charitomenosuchus (NHMUK PV R 3806), Deslongchampsina (OUMNH J.29851), Proexochokefalos (MNHN.F 1890-13), Neosteneosaurus (NHMUK PV R 2865) and machimosaurins (Yvridiosuchus: OUMNH J.1401; Lemmysuchus: LPP.M.21; Machimosaurus: SMNS 91415).

48. Premaxilla in lateral view, the anterior and anterolateral premaxillary margins are not sub-vertical, or do not extend ventrally (0), or the anterior and anterolateral margins are orientated anteroventrally and extend ventrally (1) (Fig. 53).

In one teleosauroid subclade, the anterior and anterolateral margins of the premaxilla are not sub-vertical and do not extend ventrally (state 0) when compared to the rest of the premaxilla; rather, they are anterodorsally curved in a continuous arc throughout. This condition is seen in the basal teleosauroid Plagiophthalmosuchus (NHMUK PV OR 14792) as well as Macrospondylus (PMU R161), Charitomenosuchus (NHMUK PV R 3806), Deslongchampsina (OUMNH J.29851), Proexochokefalos (MNHN.F 1890-13), Andrianavoay (NHMUK PV R 1999), Neosteneosaurus (NHMUK PV R 2865) and Machimosaurini (e.g. Lemmysuchus: NHMUK PV R 3168). In the second teleosauroid subclade, the anterior and anterolateral premaxillary margins are strongly oriented anteroventrally and extend ventrally in lateral view, giving these margins a near-vertical appearance. This condition (state 1) occurs in Mystriosaurus (NHMUK PV OR 14781), the Chinese teleosauroid (IVPP V 10098), Platysuchus (SMNS 9930), Mycterosuchus (NHMUK PV R 2617), I. potamosiamensis (PRC-11), Bathysuchus (unnumbered LPP specimen) and Aeolodon (MNHN.F.CNJ 78). It is particularly well-developed in Mystriosaurus (NHMUK PV OR 14781) and the Chinese teleosauroid (IVPP V 10098).

83. Antorbital fenestrae/cavity, absent (0) or present (1) (Fig. 52).

In most teleosauroids, a small, slit-like or subcircular antorbital fenestra is present (state 1). This condition is seen in taxa such as Mycterosuchus (NHMUK PV R 2617), Indosinosuchus (PRC-11, PRC-239), Teleosaurus (MNHN AC 8746), Charitomenosuchus (NHMUK PV R 3806), Macrospondylus (MMG BwJ 565) and Yvridiosuchus (OUMNH J.1401). However, in Proexochokefalos (MNHN.F 1890-13), Neosteneosaurus (PETMG R178) and select members of Machimosaurini (Lemmysuchus: LPP.M.21; Machimosaurus: SMNS 91415; Young et al., 2014) the antorbital fenestrae (and internal antorbital fossae) are absent (state 0).

86. Antorbital fenestrae/cavity sub-circular (0) or anteroposteriorly elongated (1) in shape (Fig. 52).

In most teleosauroid taxa, the antorbital fenestra openings are subcircular or sub-oval in shape (state 0). This condition is seen in Mystriosaurus (NHMUK PV OR 14781), the Chinese teleosauroid (IVPP V 10098), Indosinosuchus (PRC-11; PRC-239), Platysuchus (SMNS 9930), Teleosaurus (MNHN AC 8746), Mycterosuchus (NHMUK PV R 2617), Macrospondylus (SMNS 51555), Charitomenosuchus (NHMUK PV R 3320) and Yvridiosuchus (OUMNH J.1401). Most notably, in Plagiophthalmosuchus (NHMUK PV OR 14792) and Deslongchampsina (OUMNH J.29851: Johnson, Young & Brusatte, 2019), the antorbital fenestrae are large and anteroposteriorly elongated (state 1), making them appear fully oval- or teardrop-shaped. Note that this character is not applicable for those taxa that lack antorbital fenestrae: Proexochokefalos (MNHN.F 1890-13), Neosteneosaurus (PETMG R178), Lemmysuchus (LPP.M.21) and Machimosaurus (SMNS 91415; Young et al., 2014).

102. Supratemporal fenestrae, shape is either longitudinal ellipsoid or sub-rectangular (0), square-shaped (regular quadrilateral) (1), transverse (= extended) triangle (2), circular (3), triangle-shaped (three 60° points) (4), or parallelogram (5) (Fig. 55).

Teleosauroids show variance in the shape of the supratemporal fenestrae. Most taxa have a sub-rectangular shaped fenestra, in which the anteroposterior axis is greater than 10% longer than the lateromedial axis (state 0). This is the condition seen in Plagiophthalmosuchus (NHMUK PV OR 14792; MNHNL TU515), Platysuchus (SMNS 9930), the Chinese teleosauroid (IVPP V 10098), Mycterosuchus (NHMUK PV R 2617), Aeolodon (MNHN.F.CNJ 78), Sericodon (Schaefer, Püntener & Billon-Bruyat, 2018), Bathysuchus (unnumbered LPP specimen), Macrospondylus (MMG BwJ 565), Clovesuurdameredeor (NHMUK PV OR 49126), Charitomenosuchus (NHMUK PV R 3320), Pr. cf. bouchardi (Lepage et al., 2008), Proexochokefalos (MNHN.F 1890-13) and Neosteneosaurus (NHMUK PV R 2865, PETMG R178). Two teleosauroids, I. potamosiamensis (PRC-11) and Teleosaurus (MNHN AC 8746), show state 1, which is square-shaped supratemporal fenestrae; as with state 0, the anteroposterior axis is over 10% longer than the lateromedial axis. In Machimosaurini (Yvridiosuchus: OUMNH J.29850; Lemmysuchus: NHMUK PV R 3168; Mac. buffetauti: SMNS 91415; Mac. mosae: IRSNB cast, Young et al., 2014; Mac. hugii: NMS 7029) the supratemporal fenestrae are extremely elongated and parallelogram-shaped (state 5), with the lateral and medial margins, and anterior and posterior margins being sub-parallel. This state is a putative apomorphy within machimosaurins.

103. Anterior margin shape of supratemporal fenestra, no anterolateral expansion of the supratemporal fenestrae/fossae (0), or the anterior margin noticeably inclined anterolaterally (1) (Fig. 55).

In most teleosauroids, the anterior margin of the supratemporal fenestra is not anterolaterally expanded, and the anterolateral corners of the supratemporal fossae are parallel to the anteromedial corners, which makes the anterior margin of the supratemporal fenestrae appear horizontal in dorsal view (state 0). This condition is seen in the basal teleosauroid Plagiophthalmosuchus (NHMUK PV OR 17892) as well as one teleosauroid subclade (e.g Macrospondylus MMG BwJ 565; Charitomenosuchus: NHMUK PV R 3320; Proexochokefalos: MNHN.F 1890-13; Lemmysuchus: NHMUK PV R 3168; Mac. buffetauti: SMNS 91415). However, in the second subclade, the anterolateral corners of the supratemporal fossae are noticeably more inclined anteriorly than the anteromedial corners of the supratemporal fossae (state 1), giving the anterior margin an anteroposteriorly tilted appearance in dorsal view. State 1 is seen in Mystriosaurus (NHMUK PV OR 14781), the Chinese teleosauroid (IVPP V 10098), Platysuchus (SMNS 9930), Mycterosuchus (NHMUK PV R 2617), Indosinosuchus (PRC-11, PRC-239) and Aeolodon (MNHN.F.CNJ 78).

104. Supratemporal fenestrae, overall anteroposterior length is either less than or sub-equal to the anterior width (0), or is twice as long as the anterior width, or more (1) (Fig. 55).

This character is related in part to ch. 102, specifically regarding the parallelogram-shaped supratemporal fenestrae see in Machimosaurini. In most teleosauroids, the anteroposterior length of the supratemporal fenestrae is approximately the same as the width (state 0). This condition is in the basal-most form Plagiophthalmosuchus (NHMUK PV OR 14792) as well as Mystriosaurus (NHMUK PV OR 14781), Indosinosuchus (PRC-11; PRC-239), Platysuchus (SMNS 9930), Teleosaurus (MNHN AC 8746), Mycterosuchus (NHMUK PV R 2617), Bathysuchus (unnumbered LPP specimen), Aeolodon (MNHN.F.CNJ 78), Macrospondylus (MMG BwJ 565), Clovesuurdameredeor (NHMUK PV OR 49126), Charitomenosuchus (NHMUK PV R 3806) and Deslongchampsina (OUMNH J.29851). In more derived teleosauroids, the anteroposterior width of the supratemporal fenestrae are approximately twice as long as the width (state 1). This condition is in Proexochokefalos (MNHN.F 189013), Pr. cf. bouchardi (Lepage et al., 2008), Neosteneosaurus (PETMG R178) and machimosaurins (e.g. Lemmysuchus: NHMUK PV R 3168).

151. The circumorbital dorsal margins of the orbits are flush with the skull dorsal surface (0), upturned (prominent along the orbital medial margin in dorsal view, with the frontal interorbital margins being upturned) (1), or upturned along with the posterior margins (the frontal lateral process anterior margins are also upturned) (2) (Fig. 52).

In the majority of teleosauroids, the orbital dorsal margins are flush (=flattened) with the skull dorsal surface (state 0) and display no evidence of any dorsal upturn. This condition is seen in the basal teleosauroid Plagiophthalmosuchus (NHMUK PV OR 14792) as well as Mystriosaurus (NHMUK PV OR 14781), the Chinese teleosauroid (IVPP V 10098), I. kalasinensis (PRC-239), Platysuchus (SMNS 9930), Macrospondylus (MMG BwJ 565), Clovesuurdameredeor (NHMUK PV OR 49126), Charitomenosuchus (NHMUK PV R 3320), Deslongchampsina (OUMNH J.29851), Proexochokefalos (MNHN.F 1890-13), Neosteneosaurus (NHMUK PV R 2865) and Machimosaurini (e.g. Lemmysuchus: LPP.M.21). Four teleosauroid taxa (I. potamosiamensis: PRC-11; Mycterosuchus: NHMUK PV R 2617; Teleosaurus: MNHN AC 8746; Aeolodon: MNHN.F.CNJ 78) have a definitive upturning of the orbital dorsal margin (state 1), contributing to the protruding appearance of the orbits.

158. Orbit, the postorbital is excluded from the orbit posteroventral margin or only present in the posteroventral margin (0), or the postorbital reaches the orbit posteroventral margin and extensively forms part of the orbit ventral margin (1) (Fig. 56).

In most teleosauroids, the postorbital does not contact the posteroventral margin of the orbit (state 0). This is the condition seen in the basal-most teleosauroid (Plagiophthalmosuchus: MNHNL TU515, NHMUK PV OR 14792) as well as more derived taxa (e.g. Charitomenosuchus: NHMUK PV R 3806; Proexochokefalos: MNHN.F 1890-13; Yvridiosuchus: OUMNH J.29850; Mac. mosae: IRSNB cast). However, in some teleosauroid taxa, the postorbital contacts the posteroventral margin of the orbit, forming a substantial proportion of the orbital ventral margin. Due to this extension, the postorbital often overlaps the posterior part of the jugal. This condition (state 1) is found in basal teleosauroids (Mystriosaurus: NHMUK PV OR 14781; the Chinese teleosauroid: IVPP V 10098; I. potamosiamensis: PRC-11; Platysuchus: SMNS 9930; Teleosaurus: MNHN AC 8746; Mycterosuchus: CAMSM J.1420).

225. Basisphenoid, exposure anterior to the quadrates in palatal view: absent or basisphenoid terminates approximately level to the anterior extent of the quadrates (0), or basisphenoid ‘rostrum’ (= cultriform process) is exposed along the palatal surface anterior to the quadrates and continues to bifurcate the pterygoids (1) (Fig. 57).

In certain teleosauroids, when examining the anterior exposure of the basisphenoid in palatal view, this bone is either absent or terminates approximately at the level of the anterior-most quadrates (state 0). This is the condition seen in the Chinese teleosauroid (IVPP V 10098), I. potamosiamensis (PRC-11), Teleosaurus (MNHN AC 8746) and Mycterosuchus (CAMSM J.1420). In the majority of teleosauroids, the basisphenoid is well exposed along the palatal surface anterior to the quadrates and bifurcates the pterygoids (state 1), which is caused by the posterior expansion of the posterior margin of the pterygoid. State 1 is a putative synapomorphy of one teleosauroid subclade and is seen in Macrospondylus (SMNS 81699), Clovesuurdameredeor (NHMUK PV OR 49126), Charitomenosuchus (NHMUK PV R 3320), Deslongchampsina (OUMNH J.29851), Proexochokefalos (MNHN.F 1890-13), Neosteneosaurus (NHMUK PV R 2865), Yvridiosuchus (OUMNH J.403) and Lemmysuchus (LPP.M.21).

327. Teeth along the entirety of the tooth row, with sharp, pointed apices (0) or blunt, round apices (1) (Fig. 40).

Teeth that are elongate and slender with pointed apices (state 0) can clearly be seen in the basal-most form Plagiophthalmosuchus (MNHNL TU515) and in most teleosauroids (e.g. I. kalasinensis: PRC-238, PRC-239; Platysuchus: SMNS 9930; Mycterosuchus: NHMUK PV R 2617; Bathysuchus: DORCM G.05067iv; Charitomenosuchus: NHMUK PV 3806). While the taxa Mystriosaurus (HLMD V946-948, NHMUK PV OR 14781), Proexochokefalos (MNHN.F 1890-13), Deslongchampsina (OUMNH J.29851) and Neosteneosaurus (PETMG R178) possess teeth with pointed apices (and are therefore scored as state 0), it is important to note that the overall dentition of these four genera are more robust than in the other aforementioned teleosauroids. In particular, the posterior teeth of Neosteneosaurus (PETMG R178) are noticeably more conical but continue to retain a pointed apex. The tribe Machimosaurini (Jouve et al., 2016) is unique in that all members (Yvridiosuchus: OUMNH J.29850; Lemmysuchus: NHMUK PV R 3618; Machimosaurus: LMH 16387, LMH 16405, MG-8730-1, ONM NG 7, SMF 2027, SMNS 91415) have conical teeth with blunt, rounded apices (state 1) throughout the entirety of the dentition.

358. Morphology of apical enamel surface ornamentation, macroscopic anastomosed pattern absent (0) or present (1) (Fig. 40).

As with the above character, the apices of the teeth are relatively smooth and unornamented aside from the enamel ridges that reach the tip of the apex (state 0) in most teleosauroids. This is the condition seen in Plagiophthalmosuchus (MNHNL TU515), as well as Mystriosaurus (NHMUK PV OR 14781); I. kalasinensis (PRC-239); Platysuchus (SMNS 9930); Teleosaurus (Eudes-Deslongchamps, 1867); Mycterosuchus (NHMUK PV R 2617); Bathysuchus (DORCM G.05067iv); Sericodon (TCH005-151 in Schaefer, Püntener & Billon-Bruyat (2018)); Aeolodon (NHMUK PV R 1086); Macrospondylus (MNHNL TU799); Charitomenosuchus (NHMUK PV R 3806); Seldsienean (OUMNH J.1414); Deslongchampsina (OUMNH J.29851); Proexochokefalos (MNHN.F 1890-13); and Neosteneosaurus (NHMUK PV R 3701; PETMG R178). However, the tribe Machimosaurini evolved a complex ornamentation pattern (state 1); this pattern is often referred to as ‘anastomosed’, which is a rough, ‘wrinkled’ texture, visible to the naked eye, on the apical third of the tooth. Anastomosed teeth are one of the characteristic features in machimosaurins, present in all members of the group (Yvridiosuchus: OUMNH J.29850; Lemmysuchus: NHMUK PV R 3168; Machimosaurus: SMNS 91415, MG-8730-1, ONM NG 7, SMF 2027).

379. Number of sacral vertebrae: two (0) or three (1) (Fig. 43).

In the majority of teleosauroids, there are two sacral vertebrae (state 0). This condition is seen in the basal form Plagiophthalmosuchus (NHMUK PV OR 14792) as well as Platysuchus (SMNS 9930), Teleosaurus (NHMUK PV OR 32588), Mycterosuchus (NHMUK PV R 2617), Aeolodon (MNHN.F.CNJ 78), Macrospondylus (SMNS 52034), Charitomenosuchus (NHMK PV R 3806), and Neosteneosaurus (NHMUK PV R 3701, PETMG R178). However, in scored members of Machimosaurini (Lemmysuchus: NHMUK PV R 3618; Mac. mosae: IRSNB cast, Hua, 1999), three sacral vertebrae are present (state 1), which is a unique feature of this clade. The first two vertebrae are true sacrals, with the first caudal vertebra appearing and functioning as a third sacral.

410. Humerus, humeral head: confined to the proximal surface (0), gently posteriorly expanded and hooked (1), or very strongly posteriorly deflected and hooked (2) (Fig. 58).

In scored teleosauroids, the proximal area of the humerus is either gently posteriorly expanded and hooked (state 1) or strongly deflected and hooked (state 2); it is never confined to the proximal surface (state 0). In basal teleosauroids such as Plagiophthalmosuchus (NHMUK PV OR 14792), Platysuchus (SMNS 9930), Teleosaurus (OUMNH J.26801), Macrospondylus (SMNS 51957) and Mycterosuchus (NHMUK PV R 2617), the proximal humerus (or humeral head) is anteroposteriorly elongated and gently but noticeably hooked (state 1). In the teleosauroids Aeolodon (MNHN.F.CNJ 78), Charitomenosuchus (NHMUK P R 3806) and Neosteneosaurus (PETMG R178), the posterior deflection of the proximal humerus is strong, so much so that the proximal epiphysis is noticeably posterior to the distal epiphysis. This posterior deflection is much more pronounced than in any other thalattosuchian taxa.

420. Ulna, olecranon process mediolaterally compressed and greatly proximally expanded: no (0), yes (1) (Fig. 44).

Only two basal teleosauroids (Platysuchus: SMNS 9930; Macrospondylus SMNS 53422) score as 0, in which the olecranon process is neither compressed nor expanded. Interestingly, more derived teleosauroids score as state 1, where the olecranon process is both greatly expanded and mediolaterally compressed. This is seen in Mycterosuchus (NHMUK PV R 2617), Aeolodon (MNHN.F.CNJ 78), Charitomenosuchus (NHMUK PV R 3806), Neosteneosaurus (PETMG R178) and Lemmysuchus (NHMUK PV R 3168).

440. Ilium, postacetabular (= posterior) process expanded into a thin ‘fan’ shape: no (0), yes (1) (Fig. 46).

In most teleosauroids, the postacetabular (=posterior) iliac process is either anteroposteriorly shortened, robust and process-like (state 0) or anteroposteriorly expanded and mediolaterally thin, expanding it into a ‘fanlike’ shape (state 1), and is best seen in either lateral or medial view. In Charitomenosuchus (NHMUK PV R 3806), Neosteneosaurus (PETMG R178), Lemmysuchus (NHMUK PV R 3816) and Mac. mosae (Young et al., 2014), state 1 is present, with the postacetabular process lengthened into a mediolaterally thin ‘fan-like’ shape. However, it is important to note that state 1 is a putative apomorphy of derived teleosauroids, and is not seen in basal taxa such as Plagiophthalmosuchus (NHMUK PV OR 14792), Platysuchus (SMNS 9930), Teleosaurus (NHMUK PV OR 32588), Sericodon (SCR010-312 in Schaefer, Püntener & Billon-Bruyat, 2018) and Macrospondylus (SMNS 18672, SMNS 51753).

473. Ornamentation (dorsal osteoderms), the pits are either small round to ellipsoid and very densely distributed (0), large round to ellipsoid and well separated (1), irregularly shaped with an extreme variation in size, with elongate pits present on the ventrolateral surface running from the keel to the lateral margin (2), or variable in both size, shape and length that radiate in a starburst pattern (3) (Fig. 51).

While the overall shape of the dorsal osteoderms is consistent in certain areas of the body across taxa, the ornamentation (or pitting) pattern differs, most notably in the thoracic/sacral osteoderms. In most teleosauroids, the pits are large, subcircular to ellipsoid in shape, and generally well separated from one another. This condition (state 1) is seen in Plagiophthalmosuchus (NHMUK PV OR 14792), Mycterosuchus (NHMUK PV R 2617), Charitomenosuchus (NHMUK PV R 3806) and Neosteneosaurus (NHMUK PV R 2865; NHMUK PV R 3701; PETMG R178). In Charitomenosuchus (NHMUK PV R 3806), the pits are arranged in a semi-circular pattern, and the larger ones are situated more towards the lateral margins of the osteoderm. In Neosteneosaurus (NHMUK PV R 2865), most pits are exceptionally large (especially situated in the centre of the osteoderm), subcircular and fewer in number. While the osteoderm ornamentation in the holotype of Macrospondylus (MMG BwJ 595) is poorly preserved, the pits appear to be large and semi-ellipsoid with a strong anteroposterior keel. The pits also appear to be more closely placed to one another, which is observed in other Macrospondylus specimens (e.g. MMG BwJ 565; SMNS 51563; SMNS 51753), with a thin ridge separating them. In two teleosauroid taxa, the ornamental pits are small, round, and extremely densely distributed throughout the entirety of the dorsal osteoderms (state 0). This is seen in Platysuchus (SMNS 9930) and Teleosaurus (NHMUK PV R 119a). Certain teleosauroids, however, possess thoracic/sacral osteoderms with exceptionally enlarged, elongated pits; due to this elongation and large size, these pits merge with one another and become elongated grooves, especially along the lateral margins, with the pits radiating distally in a ‘starburst’ pattern (state 3). The remainder of the pits are variable in size (from small to large), irregularly shaped, and relatively close together. In addition, well-developed keels are generally present in these osteoderms. This condition is observed in machimosaurins (Lemmysuchus: NHMUK PV R 3618; Machimosaurus: ONM 1-25, SMNS 91415, Young et al., 2014). State 2, in which the pits are all irregularly shaped with extreme variation in size and have no ‘starburst’ pattern, is not present in any known teleosauroid taxa.

Cladistic Analysis: Results

Most parsimonious unweighted strict consensus

The initial New Technology search recovered 125 most parsimonious trees (MPTs) of 1,659 steps (ensemble consistency index (CI) = 0.405; ensemble retention index (RI) = 0.844; ensemble rescaled consistency index (RCI) = 0.342; ensemble homoplasy index (HI) = 0.595) (Fig. 59A). With TBR branch swapping set to 100, 260 MPTs and 1,659 steps were recovered; when set to 1,000, 2,740 MPTs and 1,659 steps were found, with the best score hitting 301 out of 1,000 times. The overall topology did not change, with or without TBR.

In this topology, Eopneumatosuchus colberti Crompton & Smith, 1980, was found to be the immediate outgroup to Thalattosuchia, which was divided into two groups: Metriorhynchoidea and Teleosauroidea. Within Teleosauroidea, Plagiophthalmosuchus was recovered as the basal-most teleosauroid. This is weakly supported, with a jackknife percentage of 66% and a Bremer support value of 1. There are two main teleosauroid families recovered (see discussion on clades below), with the taxa Clovesuurdameredeor and Macrospondylus (which form a separate polytomy) being most closely related to both of them. Within the first family (Family T) (Fig. 59A), I. kalasinensis, I. potamosiamensis, the Chinese teleosauroid (IVPP V 10098) and Mystriosaurus are unresolved with one another and are most closely related to two remaining subfamilies (see below). The taxa Teleosaurus and Platysuchus are each other’s closest relatives, with a Bremer support value of 2 and jackknife percentage of 54%. Interestingly, Mycterosuchus, Aeolodon, Bathysuchus and Sericodon form a distinct subfamily. Bathysuchus and Sericodon are sister taxa (Bremer support value of 3 and jackknife of 88%); Aeolodon is most closely related to Sericodon+Bathysuchus, and Mycterosuchus is most closely related to Aeolodon+Bathysuchus+Sericodon.

Within the second family (Family M) (Fig. 59A), there are multiple unresolved areas. Seldsienean, Deslongchampsina and Charitomenosuchus are unresolved from one another and are situated at the base of this clade (Bremer support value of 1 and jackknife of 66%). Most notably, there is a large polytomy including Pr. heberti, Pr. cf. bouchardi, Neosteneosaurus, S. rostromajor, Andrianavoay, Lemmysuchus and Yvridiosuchus, and Machimosaurini is not recovered as a monophyletic subgroup. However, when S. rostromajor is removed from the analysis (176 MPTs and 1,659 steps: CI = 0.405, RI = 0.844), Machimosaurini becomes a distinct group, with Lemmysuchus+Yvridiosuchus and Machimosaurus separated from Neosteneosaurus, Pr. heberti, Pr. cf. bouchardi and Andrianavoay (Fig. 59B). In addition, when both S. rostromajor and Andrianavoay are removed (167 MPTs, 1,659 steps: CI = 0.405, RI = 0.844), Pr. heberti and Pr. cf. bouchardi are unresolved from one another but separated from Neosteneosaurus, which by itself becomes most closely related to Machimosaurini. In all iterations (with or without the removal of S. rostromajor and Andrianavoay), the genus Machimosaurus forms its own subgroup, and relationships between the four species are mostly resolved. Machimosaurus mosae and Mac. buffetauti are unresolved from one another; and Mac. rex and Mac. hugii are sister taxa (with Mac. mosae+Mac. buffetauti being most closely related to them).

Most parsimonious weighted strict consensus

As outlined above, the analysis was run once more using extended implied weights (k = 12). Extended implied weights (EIWs) are often used to improve the quality and stability of the results, and are more beneficial for palaeontological datasets than implied weights, which only introduces bias against characters with too many missing scores (Goloboff, 2014). The New Technology search (engines tailored as above) with TBR branch swapping resulted in 47 MPTs and a score of 48.94448. Due to relative clarity in the results, this is the topology referred to when formally naming clades (see below).

The results of the EIW analysis (Fig. 60A) show a more resolved Teleosauroidea than in the original strict consensus and is more similar regarding the majority rules topology. Teleosauroidea is monophyletic, Plagiophthalmosuchus is the basal-most teleosauroid, and the two families T and M are recovered. Family T is fully resolved (Fig. 60A), in contrast to both unweighted consensus topologies. Firstly, the Chinese teleosauroid (IVPP V 10098) and Mystriosaurus form sister taxa (although, surprisingly, there are no unambiguous synapomorphies to support this), with I. kalasinensis (situated at the base of this clade) being most closely related to them; in the majority rules topology, I. potamosiamensis was the sister taxon to the Chinese teleosauroid (IVPP V 10098). Here, I. potamosiamensis is positioned as most closely related to the Teleosaurus+Platysuchus subclade and subclade composed of Mycterosuchus+Aeolodon+Bathysuchus+Sericodon. Teleosaurus and Platysuchus are once again sister taxa, and they are most closely related to Mycterosuchus and pelagic relatives, which differs from the majority rules topology. The positioning of Mycterosuchus, Aeolodon, Sericodon and Bathysuchus are the same as all previous results:

1. Sericodon and Bathysuchus are sister taxa;

2. Aeolodon is most closely related to Bathysuchus+Sericodon; and

3. Mycterosuchus is most closely related to Aeolodon+Bathysuchus+Sericodon.

The majority of Family M is also clearly resolved (Fig. 60A), with slight changes from the majority rules topology:

1. Macrospondylus, rather than Clovesuurdameredeor, is the basal-most member of this clade; and

2. Notably, and surprisingly, Machimosaurini is not found to be monophyletic, with Lemmysuchus and Yvridiosuchus forming a polytomy with Neosteneosaurus, S. rostromajor and Andrianavoay. This is similar to the original consensus rather than the majority rules topology.

Deslongchampsina is once again found to be most closely related to the subfamily containing Pr. heberti, Pr. cf. bouchardi, S. rostromajor, Andrianavoay and Machimosaurini. Proexochokefalos cf. bouchardi and Pr. heberti are sister taxa, as in the majority rules topology. When S. rostromajor is removed, (Fig. 60B), the only change results in Machimosaurini being consistently recovered, as Yvridiosuchus and Lemmysuchus are separated from Neosteneosaurus and Andrianavoay. Interrelationships within Machimosaurus taxa were identical to the majority rules topology: Mac. hugii and Mac. rex are sister taxa, and Mac. mosae is most closely related to Mac. hugii+Mac. rex than Mac. buffetauti.

There are possible explanations as to why the tribe Machimosaurini remains unresolved from certain non-machimosaurins when all taxa are included. Firstly, both S. rostromajor and Andrianavoay are both represented by fragmentary skull material (and therefore scored for a low amount of characters), which may contribute to the lack of resolution. Another crucial factor is the lack of postcranial material for Andrianavoay, S. rostromajor and Yvridiosuchus; machimosaurins have a very distinct postcranium (Hua, 1999; Young et al., 2014; Johnson et al., 2017), which may influence the appearance of the topology. Thirdly, there are no autapomorphies observed in S. rostromajor, which is a poorly preserved section of undiagnostic rostrum (see Johnson, Young & Brusatte, 2020, for more information). This may contribute to the uncertainty of its placement as either an intermediate non-machimosaurin (e.g. Neosteneosaurus) or basal machimosaurin (e.g. Yvridiosuchus).

Bayesian results

As mentioned previously, three repetitions of MrBayes were run using the following functions: (#1) standard (rates = equal); (#2), gamma distribution (rates = gamma); and (#3) gamma distribution with variability (1set applyto = (1) coding = variable). The standard Bayesian results (#1) are relatively similar to those found in the implied weighting parsimony topology (standard deviation = 0.015520; harmonic mean = −8131.53). Teleosauroidea is monophyletic, Plagiophthalmosuchus is the basal-most teleosauroid and both Families T and M are recovered. However, there are slight differences within both subclades. In Family T, Platysuchus and Teleosaurus (sister taxa) are unresolved with Mycterosuchus+relatives and the East Asian teleosauroids+Mystriosaurus, and the East Asian teleosauroids (much like in the strict consensus and majority rules topologies), and I. potamosiamensis is most closely related to the Chinese teleosauroid+Mystriosaurus. In Family M, Pr. cf. bouchardi and Pr. heberti are not sister taxa, but rather Pr. cf. bouchardi is found to be most closely related to Neosteneosaurus+Andrianavoay+S. rostromajor+Machimosaurini.

In the gamma Bayesian test (#2), the results (standard deviation = 0.019863; harmonic mean = −7785.47) (Fig. 61) are similar to that seen in the standard Bayesian analysis, but with two differences:

1. Charitomenosuchus, Seldsienean and Deslongchampsina are in a polytomy; and

2. Pr. cf. bouchardi and Pr. heberti are in a polytomy.

The gamma variation MrBayes analysis (#3) (standard deviation = 0.017365; harmonic mean = −8130.41) produced a topology identical to that seen in the standard Bayesian analysis. In all Bayesian analyses, S. rostromajor is most closely related to Machimosaurini.

Clades and Their Synapomorphies

Within this section, the synapomorphies uniting major clades are highlighted and discussed. A period and then the synapomorphic character state number follow the character numbers. We have decided to establish the clade names under both the ICZN Code and the International Code of Phylogenetic Nomenclature (hereafter referred to as the PhyloCode) to ensure nomenclatural stability. First the clade will be established under the ICZN Code, giving its diagnosis, then the clade will be established under the PhyloCode, giving its phylogenetic definition.

Teleosauroidea Geoffroy Saint-Hilaire, 1831

Classification note. Teleosauroidea is a ‘family group’ clade established under the ICZN Code, at the superfamily rank.

Nominal authority. The nominal authority is based on Article 36.1 of the ICZN Code (Principal of Coordination, applied to family group names).

Description. The superfamily Teleosauroidea is supported by multiple synapomorphies. These include absence of a sclerotic ring (163.0), postorbital medial to the jugal on the postorbital bar (173.0), straightened (sub-rectangular) anterior maxilla in palatal view (184.1), relatively reduced occipital tuberosities (203.1), paired ridges located on the medial ventral surface of the basisphenoid (223.1), a distinctly spatulate anterior dentary with the maximum width at the D3-D4 couplet (254.2), D3 occludes against the premaxillary-maxillary suture (331.0), coracoid with a fan-shape distal end and a triangular-shaped proximal end (402.1), a scapular blade as wide as or narrower than the glenoid region (405.1) and presence of caudal armour (493.0), as well as scoring the ‘pholidosaurid beak’ as inapplicable (47.-). One of these characters is new to the dataset, and another character (47) was re-written and re-scored. It is important to note that in teleosauroids, certain characters score differently than Pelagosaurus but are the same for other basal metriorhynchoids (e.g. Teleidosaurus). These include a slightly convex or flat frontal (121.0), a broadly curved anterior margin of the external mandibular fenestra (260.0), and well-defined apicobasally aligned ornamental ridges on the dentition (357.4),

Comments. Geoffroy Saint-Hilaire (1831: 34) initially defined teleosauroids (interpreted as ‘Teleosauridae’) as a distinct clade, referring to “un cachet crocodilien” (“a crocodilian character”). This suggests that he is describing the main features of teleosauroids, although he did not assign a name to this clade (Johnson, Young & Brusatte, 2020). He then proceeds to list the following features as definitive for the group:

1. Large ‘vertical holes’ (supratemporal fenestrae);

2. Vertically placed eyes;

3. A parietal bone that does not intervene between the jugal and temporal;

4. Two arches (“l’une supérieure jugo-temporale, l’autre inférieure maxillo-tympanique”: “one superior jugo-temporal, the other lower maxillofacial”);

5. Development of the nasal (cranio-respiratory) canal and temporal region; and

6. ‘Beak-like’ snout.

At the end of this description, Geoffroy Saint-Hilaire (1831: 37–38) writes ‘Cette dernière combinaison remarquable dans les êtres téléosauriens devient des éléments caractéristiques pour une nouvelle famille; des éléments d’une puissance et d’une valeur à rendre en effet obligatoires les distinctions zoologiques de cette famille, c’est-à-dire l’érection des genres Téléosaurus et Sténéosaurus’ (‘This last remarkable combination in teleosaurs becomes characteristic elements for a new family; elements of power and value to make compulsory the zoological distinctions of this family, that is to say the erection of the genera Teleosaurus and Steneosaurus’). Geoffroy Saint-Hilaire (1831: 37) considered ‘la région supérieure et vers la fin de l’arrière-crâne; et d’autre part le museau’ (‘the upper region and towards the end of the back of the skull; and (on the other hand) the snout’), along with ‘le canal nasal et le palais’ (‘the nasal canal and the palat’), to be the most important features when distinguishing teleosauroid species. After Geoffroy Saint-Hilaire’s (1831) work, teleosauroids continued to be traditionally grouped together based on their ‘longirostrine’ skull, dorsally directed orbits and high tooth count (Karl et al., 2008; Young & Andrade, 2009; Ballell et al., 2019). However, recent studies (Young et al., 2014; Foffa et al., 2019; Sachs et al., 2019a) have shown that there is more variation in the teleosauroid cranium than initially thought, and the shape of the skull and number of teeth cannot purely be relied on to define this clade.

Teleosauroidea Young & Andrade, 2009 nomen cladi conversum

Phylogenetic definition. The largest clade within Thalattosuchia containing Teleosaurus cadomensis, but not Metriorhynchus geoffroyii Von Meyer, 1832. Young & Andrade (2009) initially defined the superfamily Teleosauroidea as the most inclusive clade consisting of Teleosaurus cadomensis, but not Metriorhynchus geoffroyii. This is a maximum-clade, or stem-based, definition.

Reference phylogeny. Phylogenetic analyses presented herein, see Figs. 59–61, 63 and 64.

Composition. Plagiophthalmosuchus, Teleosauridae (comprising of the Chinese teleosauroid, Indosinosuchus, Mystriosaurus, Teleosaurinae (comprising of Platysuchus and Teleosaurus)), and Aeolodontinae (comprising of Aeolodon, Bathysuchus, Mycterosuchus and Sericodon) and Machimosauridae (comprising of Charitomenosuchus, Clovesuurdameredeor, Deslongchampsina, Macrospondylus, Seldsienean and Machimosaurinae (comprising Andrianavoay, Neosteneosaurus, Proexochokefalos and Machimosaurini (comprising Lemmysuchus, Machimosaurus and Yvridiosuchus))).

Diagnostic apomorphies. 47.-; 163.0; 173.0; 184.1; 203.1; 223.1; 254.2; 331.0; 402.1; 405.1; 493.0. (From the dataset herein, the same characters as the ICZN Code description.)

Teleosauridae (Family T) Geoffroy Saint-Hilaire, 1831

Classification note. Teleosauridae is a ‘family group’ clade established under the ICZN Code, at the family rank.

Original Definition Comment. ‘Teleosauridae’ was originally erected and defined by Geoffroy Saint-Hilaire (1825, 1831) and encompassed all teleosauroid species (as discussed above). However, herein Teleosauridae is restricted to the following taxa: the genus Indosinosuchus, Mystriosaurus laurillardi, Teleosaurus cadomensis, Platysuchus multiscrobiculatus, Aeolodon priscus, Mycterosuchus nasutus, Sericodon jugleri, Bathysuchus megarhinus and the Chinese teleosauroid (IVPP V 10098).

Description. A number of synapomorphies supports the monophyly of Teleosauridae. These include anteriorly or anterodorsally oriented external nares (34.0), anterior and anterolateral premaxillary margins that are anteroventral and extend ventrally (48.1), supratemporal fenestrae with noticeably inclined anterior margins (103.1), postorbital overlapping the jugal (158.1), a horizontal pterygoid flange (198.0) and the basisphenoid terminates at the anterior quadrates (225.0).

Teleosauridae Geoffroy Saint-Hilaire, 1831 nomen cladi conversum

Phylogenetic definition. The largest clade within Teleosauroidea containing Teleosaurus cadomensis, but not Plagiophthalmosuchus gracilirostris and Machimosaurus hugii. This is a maximum-clade, or stem-based, definition.

Reference phylogeny. Phylogenetic analyses presented herein, see Figs. 59–61, 63 and 64.

Composition. The Chinese teleosauroid, Indosinosuchus, Mystriosaurus, Teleosaurinae (comprising of Platysuchus and Teleosaurus) and Aeolodontinae (comprising of Aeolodon, Bathysuchus, Mycterosuchus and Sericodon).

Diagnostic apomorphies. 34.0; 48.1; 103.1; 158.1; 198.0; 225.0. (From the dataset herein, the same characters as the ICZN Code description.)

Unnamed clade: the Chinese teleosauroid IVPP V 10098 + Mystriosaurus laurillardi

Comments. Interestingly, there are no unambiguous synapomorphies that unite this clade, despite its stable position within the weighted parsimonious analysis (Figs. 60A and 60B). This unnamed clade shares one character with Neosteneosaurus and machimosaurins (nasals and maxillae are not elongated: 6.0) and one character with Mac. buffetauti and Mac. mosae (anteroposterior premaxillary length is less than 25% of total rostrum length: 43.0).

Teleosaurinae Vignaud, 1995 (Teleosaurus + Platysuchus)

Classification note. Teleosaurinae is a ‘family group’ clade established under the ICZN Code, at the subfamily rank.

Nominal authority. The nominal authority is based on Article 36.1 of the ICZN Code (Principal of Coordination, applied to family group names).

Description. The subfamily Teleosaurinae consists of the genera Platysuchus and Teleosaurus, and there are four characters that unite them as sister taxa. These include both the tooth row and quadrate condyle being below the level of the occipital condyle but are unaligned with the tooth row at a lower level (2.5), the frontal-postorbital suture is lower than the intertemporal bar (131.1), densely distributed osteoderms with small round to ellipsoid pits (473.0), and presacral dorsal osteoderms are strongly curved (480.1).

Comments. Vignaud (1995) initially diagnosed the subfamily Teleosaurinae as that containing Platysuchus and all Teleosaurus taxa. Here, Teleosaurus is currently limited to just one species, but follows the same proposal put forth in Vignaud (1995), in that Platysuchus is most closely related to Teleosaurus.

Teleosaurinae Vignaud, 1995 nomen cladi conversum

Phylogenetic definition. The largest clade within Teleosauroidea containing Teleosaurus cadomensis, but not Aeolodon priscus and Indosinosuchus potamosiamensis. This is a maximum-clade, or stem-based, definition.

Reference phylogeny. Phylogenetic analyses presented herein, see Figs. 59–61, 63 and 64.

Composition. Platysuchus and Teleosaurus.

Diagnostic apomorphies. 2.5; 131.1; 473.0; 480.1. (From the dataset herein, the same characters as the ICZN Code description.)

Aeolodontinae subfam. nov. (Mycterosuchus + Aeolodon + Bathysuchus + Sericodon)

Classification note. Aeolodontidae is a ‘family group’ clade established under the ICZN Code, at the subfamily rank. urn:lsid:zoobank.org:act:E7A8EDC8-8DF8-4799-AA09-5D6B9287E201.

Description. A number of synapomorphies, notably in the premaxilla, supports the subfamily Aeolodontinae, which includes the genera Mycterosuchus, Aeolodon, Sericodon and Bathysuchus. These include an ‘8’shaped premaxilla in anterior view (56.1), reduced basioccipital tuberosities (230.0), laterally oriented P1 and P2 (294.2), P1 and P2 do not form a couplet but are situated on the anterior margin of the premaxilla (295.1), P1 and P2 are both on the same transverse plane (298.1) and the anterior margin between the P2-P3 is sub-rectangular, with the P3 being clearly lateral to the P2 (299.1). Four out of six characters are new to this dataset.

Comments. Aeolodontinae is also always recovered as a monophyletic subclade, regardless of changing taxa and/or character scores and whether the dataset is run using parsimony or Bayesian criteria. It is interesting to note that, while similar in many aspects concerning the skull (namely the premaxillae), the postcranial material of Mycterosuchus differentiates vastly from other members of the group. For example, the proximal humerus is very strongly posteriorly deflected and hooked in Aeolodon, similar to members of Machimosauridae (e.g. Charitomenosuchus, Neosteneosaurus). In Mycterosuchus, the proximal humerus is also hooked, but weakly so, and is more club-shaped. The tuberculum and articular facet of the largest dorsal ribs are positioned directly in the middle, which is more similar to Charitomenosuchus and opposed to the medial edge position in Aeolodon. Other unique postcranial features to Mycterosuchus include a longer ulna than radius, an elongated pubic shaft, an enlarged anteromedial femoral tuber and the calcaneal tuber being approximately 25% larger than the astragalus (as discussed above). It is likely that the unique skull characteristics of these taxa are what is supporting this subfamily as monophyletic.

While postcranial materials of Aeolodon are well preserved in both specimens (NHMUK PV R 1086 and MNHN.F.CNJ 78), and partially preserved in Sericodon (see Schaefer, Püntener & Billon-Bruyat, 2018), it is important to note that there are no postcranial bones of Bathysuchus currently recorded. A full, comprehensive comparison of the postcrania of Aeolodon and Sericodon is essential, to examine if Sericodon possesses a reduced appendicular skeleton similar to that seen in Aeolodon, which has been hypothesized to be more pelagic than other teleosauroids (see below, as well as Foffa et al. (2019)).

Aeolodontinae nomen cladi novum

Registration number. urn:lsid:zoobank.org:act:E7A8EDC8-8DF8-4799-AA09-5D6B9287E201.

Phylogenetic definition. The largest clade within Teleosauroidea containing Aeolodon priscus but not Indosinosuchus potamosiamensis and Teleosaurus cadomensis. This is a maximum-clade, or stem-based, definition.

Reference phylogeny. Phylogenetic analyses presented herein, see Figs. 59–61, 63 and 64.

Composition. Aeolodon, Bathysuchus, Mycterosuchus and Sericodon.

Diagnostic apomorphies. 56.1; 230.0; 294.2; 295.1; 298.1; 299.1. (From the dataset herein, the same characters as the ICZN Code description.)

Unnamed clade: Aeolodon + Bathysuchus + Sericodon

Comments. Interestingly, there are no unambiguous synapomorphies that unite this clade, despite its stable position within the above analyses. This unnamed clade shares two characters with Plagiophthalmosuchus and I. potamosiamensis: no ornamentation on prefrontal (12.1) and lacrimal (13.1); and one character with Charitomenosuchus, Seldsienean, Deslongchampsina and Machimosaurinae (see below): frontal ornamentation restricted to the centre of the bone (15.1).

Unnamed clade: Sericodon + Bathysuchus

Synapomorphies. 296.1; 339.1.

Comments. Sericodon and Bathysuchus are united by two characters: a strong lateral expansion of the premaxillae so that P3 and P4 are aligned on the lateral plane of the external margin (296.1) and presence of carinae on the apical third of the tooth (339.1). Despite only two dental synapomorphies, Sericodon and Bathysuchus are recovered as sister taxa in all analyses.

Machimosauridae Jouve et al., 2016 fam. nov. (Family M)

Classification note. Machimosauridae is a ‘family group’ clade established under the ICZN Code, at the family rank. urn:lsid:zoobank.org:act:81FB2470-D7E7-4E3E-814B-2AAE996BE5AA.

Nominal authority. The nominal authority is based on Article 36.1 of the ICZN Code (Principal of Coordination, applied to family group names).

Description. The family Machimosauridae is united by a number of characters; these include the dorsally oriented external nares (34.1), the premaxillary anterior and anterolateral margins are not sub-vertical and do not extend ventrally (48.0), the premaxilla-maxilla suture is sub-rectangular and slightly interdigitating (most noticeably near the midline) (58.1), no anterolateral expansion of the supratemporal fenestrae (103.0), the postorbital excluded from the orbit posteroventral margin (158.0), mostly horizontal pterygoid with a distinct posterolateral angle (198.1) and cultriform process of the basisphenoid exposed and bifurcates the pterygoids (225.1).

Machimosauridae nomen cladi novum

Registration number. urn:lsid:zoobank.org:act:81FB2470-D7E7-4E3E-814B-2AAE996BE5AA.

Phylogenetic definition. The largest clade within Teleosauroidea containing Machimosaurus hugii, but not Plagiophthalmosuchus gracilirostris and Teleosaurus cadomensis. This is a maximum-clade, or stem-based, definition.

Reference phylogeny. Phylogenetic analyses presented herein, see Figs. 59–61, 63 and 64.

Composition. Charitomenosuchus, Clovesuurdameredeor, Deslongchampsina, Macrospondylus, Seldsienean and Machimosaurinae (comprising Andrianavoay, Neosteneosaurus, Proexochokefalos and Machimosaurini (comprising Lemmysuchus, Machimosaurus and Yvridiosuchus)).

Diagnostic apomorphies. 34.1; 48.0; 58.1; 103.0; 158.0; 198.1; 225.1. (From the dataset herein, the same characters as the ICZN Code description.)

Machimosaurinae Jouve et al., 2016 subfam. nov. ( Proexochokefalos + Andrianavoay + Neosteneosaurus + Machimosaurini)

Classification note. Machimosaurinae is a ‘family group’ clade established under the ICZN Code, at the subfamily rank. urn:lsid:zoobank.org:act:918AC1F1-AC04-41D1-91DA-E2D25939EAB9.

Nominal authority. The nominal authority is based on Article 36.1 of the ICZN Code (Principal of Coordination, applied to family group names).

Description. The subfamily Machimosaurinae is supported by a handful of characters including the supratemporal fenestra length being twice as long as the width (104.1), a shallow Meckelian groove (269.1), a sharply curved angular (270.1) and non-procumbent dentition throughout the entirety of the jaws (325.0). Two of these characters are new to the dataset.

Machimosaurinae nomen cladi novum

Registration number. urn:lsid:zoobank.org:act:918AC1F1-AC04-41D1-91DA-E2D25939EAB9.

Phylogenetic definition. The largest clade within Teleosauroidea containing Machimosaurus hugii but not Deslongchampsina larteti and Charitomenosuchus leedsi. This is a maximum-clade, or stem-based, definition.

Reference phylogeny. Phylogenetic analyses presented herein, see Figs. 59–61, 63 and 64.

Composition. Andrianavoay, Neosteneosaurus, Proexochokefalos and Machimosaurini (comprising Lemmysuchus, Machimosaurus and Yvridiosuchus).

Diagnostic apomorphies. 104.1; 269.1; 270.1; 325.0. (From the dataset herein, the same characters as the ICZN Code description.)

Features uniting the genus Proexochokefalos

Synapomorphies. 66.0.

Comments. The sole character supporting Proexochokefalos heberti and Proexochokefalos cf. bouchardi as sister taxa is the lack of a midline cavity (= trench) on the nasals, instead being flat (66.0).

Machimosaurini Jouve et al., 2016 (Yvridiosuchus + Lemmysuchus + Machimosaurus)

Classification note. Machimosaurini is a ‘family group’ clade established under the ICZN Code, at the tribe rank.

Description. A number of character states support the monophyly of Machimosaurini. These include parallelogram-shaped supratemporal fenestrae (102.5), blunt apices (327.1), no curvature in the middle to posterior dentition (345.0), false ziphodont serrations restricted to posteriorly-placed tooth crowns (349.2), incipient ziphodont carinae (351.2), rounded true denticles (352.1), all teeth microziphodont (353.1), strongly developed anastomosed pattern on the apices (358.1), three sacral vertebrae (379.1), sub-square ischial plate (449.1), ventrally angled tibial tuberosity (464.1), and keeled osteoderms with variable and elongated pits (473.3). Two of these characters are new to the dataset. Jouve et al. (2016) initially described the tribe Machimosaurini based on the following characteristic features: (1) shortened rostra; (2) enlarged supratemporal fenestrae; (3) reduced tooth counts; and (4) blunt, ornamented dentition.

Comments. Certain characteristics of machimosaurins, particularly their teeth, have been documented for many years; Mac. hugii was first described by von Meyer in 1837, who made a particular comment about the dentition: ‘…stumpfkonischen und dicht gestreiften Zähnen besonders charakteristisch herauszustellen…’ (‘…particularly (conspicuous in) conical and densely striped teeth…’) (Von Meyer, 1837: 560). Sauvage & Liénard (1879: 7) noted ‘L. forme des vertèbres, la disposition des écussons, la composition de la tête (…), la forme et l’ornamentation des dents…’ (‘The shape of the vertebrae, the arrangement of the osteoderms, the composition of the head (…), the shape and ornamentation of the teeth…’) when describing Mac. mosae. Phillips (1871: 184–185) also defined the teeth of Yvridiosuchus (known then as Teleosaurus brevidens; see Johnson, Young & Brusatte, 2019) as ‘…rather short (teeth)…a little curved, uniformly striated, the striae growing more prominent toward the point and finer toward the base… (a) slight trace of bicarination on these teeth, near the apex, which is usually blunt…’; he appears to be referring to the anastomosing pattern. Andrews (1913: 132), made note of the third sacral vertebra in Lemmysuchus, saying ‘…a remarkable condition is found, there being apparently three sacrals… (seems to be) that the ribs of the first caudal have greatly enlarged and resemble sacral ribs…’ However, Andrews (1913) thought this to be a unique feature in Lemmysuchus, not taking into context the same condition seen in species of Machimosaurus.

Recent papers have also highlighted several of these features, including: detailed descriptions of the dentition (Young & Steel, 2014; Young et al., 2015a; Jouve et al., 2016); specific features of the skull (Hua, 1996; Young et al., 2014; Fanti et al., 2016; Johnson et al., 2017; Johnson, Young & Brusatte, 2019); reduction in the pelvic bones (Johnson et al., 2017); and the unique sacral anatomy (Martin & Vincent, 2013; Young et al., 2014; Johnson et al., 2017).

Machimosaurini Jouve et al., 2016, nomen cladi conversum

Phylogenetic definition. The largest clade within Teleosauroidea containing Machimosaurus hugii, but not Neosteneosaurus edwardsi. This is a maximum-clade, or stem-based, definition.

Reference phylogeny. Phylogenetic analyses presented herein, see Figs. 59–61, 63 and 64.

Composition. Lemmysuchus, Machimosaurus and Yvridiosuchus.

Diagnostic apomorphies. 102.5; 327.1; 345.0; 349.2; 351.2; 352.1; 353.1; 358.1; 379.1; 449.1; 464.1; 473.3. (From the dataset herein, the same characters as the ICZN Code description.)

Features uniting the genus Machimosaurus

Unambiguous Synapomorphies. 7.0.

Ambiguous Synapomorphies. 32.0; 288.3; 292.-; 293.-; 294.-; 297.-; 300.-; 395.{01}; 406.1.

Comments. There are multiple features unique to the genus Machimosaurus; however, there is only one definitive character that is preserved in all species: a wider than higher rostrum (7.0). All ambiguous synapomorphies are found in both Mac. buffetauti and Mac. mosae, but are scored as (?) in Mac. hugii and Mac. rex due to lacking or fragmentary material. These synapomorphies include simple, straight-lined dentary neurovascular foramina (32.0), three premaxillary alveoli (288.3), the tuberculum and articular facet of dorsal ribs positioned halfway in the middle (395.{01}), scapula with a strongly concave anterior edge (406.1), and inapplicability of ch. 292–294, 297 and 300.

Discussion

Conclusions

Despite an increase in morphological work within the past decade, the evolutionary relationships of teleosauroids are poorly understood and little studied, and thus their macroevolutionary patterns are rarely evaluated. One major issue is the genus Steneosaurus, which is often recovered as paraphyletic or polyphyletic in phylogenetic analyses. Following on our recent re-classification of Steneosaurus as a nomen dubium and an invalid genus (Johnson, Young & Brusatte, 2020), we herein presented an in-depth phylogenetic evaluation of Teleosauroidea. We firstly proposed the following changes to teleosauroid nomenclature, as a direct result of the invalidity of Steneosaurus: seven new generic names (Plagiophthalmosuchus, Clovesuurdameredeor, Seldsienean, Charitomenosuchus, Proexochokefalos, Andrianavoay and Neosteneosaurus) and one new species (Indosinosuchus kalasinensis); and the resurrection of three historical genera (Macrospondylus, Aeolodon and Sericodon). Secondly, we described 38 new characters and 19 additional characters that are important and distinctive in teleosauroid morphology and discussed how these characters differ between taxa. Thirdly, we listed the results of the phylogenetic analyses based on our updated H+Y data matrix, containing 153 taxa (including 27 teleosauroids) and 502 osteological characters. Our results showed that both parsimony and Bayesian topologies are relatively consistent with one another. Next, we propose and define the following taxonomic clades: the families Teleosauridae (re-defined) and Machimosauridae, and the subfamilies Aeolodontinae and Machimosaurinae (which includes Machimosaurini). Finally, we evaluated the ecomorphology and distribution of teleosauroids, based on our new phylogeny. Teleosauridae and Machimosauridae are morphologically distinct, with differing biogeographic distributions (Teleosauridae is Laurasian and Machimosauridae is Sub-Boreal European-Gondwanan), habitat preferences and feeding strategies. The phylogeny infers that the teleosaurids were overall more phenotypically plastic than machimosaurids, with an east-Asian freshwater clade, a nascent pelagic clade, and a heavily armoured clade; machimosaurids were dominant in terms of abundance and dispersal, with a linear pattern of morphological changes. By evaluating our updated phylogeny, it is clear that teleosauroids were, in terms of morphology, ecology and geography, more diverse than previously thought.

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