A new family of scorpionflies (Insecta; Mecoptera) from the Lower Cretaceous of England
Introduction
The records of fossil scorpionflies from the period between the Early Permian and Early Cretaceous demonstrate the group was numerous and diverse. The Cretaceous climate and biotic changes strongly affected the evolution of insects (Szwedo and Nel, 2015). Thereafter the abundance of Mecoptera in fossil assemblages decreases, such as for the Bittacidae (Kopeć et al., 2016). From the Late Cretaceous through the Paleogene, finds of scorpionflies are not so common and the family composition gradually develops a modern appearance (Novokshonov, 2002). However in the Eocene, the peak of Panorpoid diversity was observed (Archibald et al., 2013). Extant representatives of Mecoptera are only the remnants of a formerly much more diverse group. Today more than 600 living species are assigned to only nine families, (Cai et al., 2008, Bicha, 2010). While the fossil insect database EDNA (Mitchell, 2015) currently comprises 776 species in 231 genera, assigned to 40 families and this number is continually changing.
Despite a considerable number of papers dealing with fossil Mecoptera, only part of the accumulated material has been treated taxonomically. At the end of the 20th century the list of scorpionfly families was considered to be virtually complete (Novokshonov, 1997). However, new families are still being described: Sibiriothaumatidae (Sukatcheva and Novokshonov, 1998), Nedubroviidae from the Late Permian/Early Triassic (Bashkuev, 2011), Eorpidae from the Eocene (Archibald et al., 2013), Australochoristidae from the Early Cretaceous (Krzemiński et al., 2015) and the new family from England described here. As yet Mecoptera from the Lower Cretaceous Weald Clay Group of southern England have received little attention. Although they are rare there are certainly several taxa present though most specimens have not been studied in detail. Jarzembowski, 1984, Jarzembowski, 2011 recorded the presence of Orthophlebiidae and figured a specimen of Mesopanorpa sp.; Ross and Cook (1995) mention Orthophlebiidae as occurring in the Upper Weald Clay (Barremian) at Smokejacks Brickworks, Surrey, and Petrulevičius and Jarzembowski (2004) described a new genus and species of Bittacidae, Antiquanabittacus nanus, from the Lower Weald Clay (Hauterivian) of Clockhouse Brickworks, Surrey, restudied by Kopeć et al. (2016).
This paper was started many years ago by Novokshonov and Ross, however due to the first author's untimely death the paper was put on hold. It has now been completed thanks to the additional authors. Ross and Cook also planned to write a paper on the geology of Rudgwick Brickworks but this was never finished. Given the site is no longer operational this is a good opportunity to publish more information about this site.
The discovery in the Mesozoic of England of scorpionflies not assignable to any known family is of interest. The new family's description and a discussion of its systematic position within the order Mecoptera are given below.
Section snippets
Materials and methods
The study was based on seven fossils from the Upper Weald Clay Formation (lower Barremian, ∼129.4–125 Ma) of Rudgwick Brickworks, Sussex and Smokejacks Brickworks, Surrey in southern England. The specimens are deposited in the Booth Museum of Natural History, Brighton, England (BMB) and Natural History Museum, London, England (NHMUK).
The specimens were studied with the use of a Leica MZFLII stereomicroscope, under reflected light. Drawings were made from the photographs and digitally processed
Localities
The specimens were found in two localities in the Wealden Supergroup (Lower Cretaceous) of the Weald, southern England. One species came from Rudgwick Brickworks, West Sussex and the other from Smokejacks Brickworks, Surrey; both in the Upper Weald Clay Formation (Barremian, ∼129.4–125 Ma). A map showing their locations and a generalised stratigraphy of the Weald Clay Group (after Ross in Rasnitsyn et al., 1998) showing the relative positions of the sites is shown in Fig. 1. For more
Systematic palaeontology
Order Mecoptera Packard, 1886
Discussion
Records of the interesting new family Englathaumatidae from southern England support the view of a high evolutional potential of very diverse Mecoptera in the Early Cretaceous. At first glance, the shape of the wing and dense venation of the new family resembles the Jurassic-recent Eomeropidae (Willmann, 1981, Willmann, 1989) as is reflected in the name (after Notiothauma, genus in this family). However the venation is less polymerized than in Eomeropidae and the “eomeropid triadic branching”
Concluding remarks
Finding new fossils in two localities in southern England, dated as early Barremian enables the description of a new family, new genus and two new species. The name Englathaumatidae has been a nomen nudum since the year 2002 due to the first author's untimely death. The name was published in text and included in a phylogenetic tree but never formally described or illustrated. The unique combination of a few characters justifies establishment of a new family. The combination of characters, such
Acknowledgements
We would like to thank Mr John A. Cooper, Keeper of Natural Sciences at the Booth Museum of Natural History in Brighton, England, for the kind help and loan of the holotype of E. crabbi; to Claire Mellish for access to the fossil insect collections at the NHMUK and to Phil Crabb, formerly of the NHMUK, for photography. We are very grateful to Aleksandr Rasnitsyn and Alexey Bashkuev for their very useful, comprehensive and thorough comments to the first version of the manuscript. The research
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