Cedariidae Raymond 1937

Family Cedariidae Raymond, 1937

Discussion. Jell (in Jell and Adrain, 2003) included Bonneterrina Lochman, 1936 (= Holstonia Resser, 1938; = Piedmontia Resser, 1938), Carinamala Palmer, 1962, Cedaria Walcott, 1924, Cedarina Lochman, 1940, Henadoparia Öpik, 1967, Jimachongia Yuan and Yin, 1998, and Vernaculina Lochman and Hu, 1961, in Cedariidae. Of these, Carinamala, Cedaria, Cedarina, and Vernaculina are exclusively Laurentian (including reports from the Laurentian-affinity Argentine Precordillera: Borello, 1965; Bordonaro, 2003). Bonneterrina is mainly Laurentian, but Siberian (Č ernyševa, 1960; Rozova, 1964; Egorova et al., 1982) and Uralian (Č ernyševa, 1968) species have been assigned. The genus is not demonstrably a cedariid. Neither of the two specimens assigned to B. prima Lochman, 1936, preserve the posterior projections, and the type of facial sutures present is unknown. The nature of the sutures is also unknown on the other Laurentian species assigned to the genus, none of which are well known. It is far from clear if they are all related to each other or to B. prima. The extra-Laurentian species are uniformly poorly known and additional material and better illustrations are required to confirm their status as cedariids. Pegel (2000, fig. 11.3) attributed a Siberian cranidium to Bonneterrina, but it lacks a cedariform suture. Henadoparia and Jimachongia are monotypic. Henadoparia is from the Mindyallan (Marjuman equivalent) of Australia, while Jimachongia is from strata of similar age in South China.

Henadoparia was assigned to Cedariidae by Öpik (1967, p. 348) on the basis of comparison by A.R. Palmer (verbal communication to Öpik reported by Öpik) and by Öpik himself of its only species, H. integra Öpik, 1967, to " Cedaria " woosteri (Whitfield, 1882), from the Cedaria Zone of the Eau Claire Formation of the Upper Mississippi Valley (Minnesota and Wisconsin). " Cedaria " woosteri has highly modified facial sutures which surround the eye and part of the field, but which do not cut across the cephalic borders. This morphology is apparently unique within Trilobita, and the species was the subject of restudy by Hughes et al. (1997), who did not assign it to Cedariidae, considering that (Hughes et al., 1997, p. 103) "The phylogeny of primitive libristomates is currently too poorly known to confirm that sister taxa of "C." woosteri occur within Cedaria." In any event, there is little detailed similarity between H. integra and "C." woosteri, which is now known from good photographs provided by Hughes et al. (1997). Henadoparia integra had functional facial sutures of standard opisthoparian type. They are not cedariform. The species also has a relatively vaulted glabella with complex, well impressed furrows. Laurentian cedariids have uniformly low glabellae with very shallow furrows. While cephala of H. integra and "C." woosteri have similar overall dimensions, there is little to support aclose phylogenetic relationship.

In addition to the Laurentian taxa listed above, Paracedaria Lochman and Duncan, 1949, appears to be a cedariid. Jell (in Jell and Adrain, 2003) assigned the genus to Llanoaspididae Lochman in Lochman and Duncan, 1944, but cranidia of all of its species appear to have a cedariform suture. They differ from species of Cedarina in having smaller, more anteriorly positioned eyes and in having firmly impressed pleural and interpleural furrows which extend across the pygidial border to the margin.

" Cedaria " woosteri almost certainly represents a morphologically derived cedariid, but Henadoparia integra does not appear to be ingroup Cedariidae. Instead, it may belong to Proasaphiscidae Zhang, 1963. Jago and Cooper (2005, p. 671) considered Sinocoosella Yuan and Yin, 1998, to be a junior subjective synonym of Henadoparia, considering that "there is no significant difference between" the genera. Independently, however, Peng et al. (2004, p. 25) considered Sinocoosella to be a junior subjective synonym of the proasaphiscid Adelogonus Öpik, 1967. The latter opinion is supported herein, and the pygidium of H. integra (Öpik, 1967, pl. 37, fig. 5) compares closely with that of A. hunanensis Peng, Babcock, and Lin, 2004 (Peng et al., 2004, pl. 9, figs. 4, 5).

Yuan and Yin (1998, p. 159) erected Jimachongiinae as a new subfamily of Cedariidae. In it they included their new, monotypic, Jimachongia from the Glyptagnostus stolidotus Zone of South China, along with Yokusenia Kobyashi, 1935a, and Xiaoshiella Lu and Qian, 1983, each known from several species from the lower Changshanian Chuangia Zone (Steptoean equivalent) of the North China block, and the Laurentian upper Marjuman taxa Verditerrina Robison, 1988, and (with question) Wandelella Robison, 1988. While the affinities of several of these genera are somewhat uncertain, this comprises an almost certainly polyphyletic assemblage, none of whose members is demonstrably ingroup Cedariidae. Yokusenia was assigned to Pterocephaliidae Kobyashi, 1933, by Qian (1994), Fortey (1994), and Jell and Adrain (2003). Xiaoshiella was assigned to Anomocaridae Poulsen, 1927, by Qian (1994) and to Pterocephaliidae by Jell and Adrain (2003). Robison (1988) considered Verditerrina of uncertain familial affinity, but Westrop and Ludvigsen (2000) demonstrated convincingly that it belongs to Menomoniidae Walcott, 1916 a. Robison (1988, p. 98) also regarded the family affinity of Wandelella as uncertain, but compared it with Pianaspis Saito and Sakakura, 1936, of the Papyriaspididae Whitehouse, 1939, to which Jell and Adrain (2003) subsequently assigned it.

Hence, unequivocal cedariids are restricted to Laurentia, and the family may prove to be endemic to that paleocontinent. The group is entirely of Marjuman age.