Itilochelys rasstrigin gen. et sp. nov, a new hard-shelled sea turtle (Cheloniidae sensu lato) from the Lower Paleocene of Volgograd Province, Russia

I.G. Danilov, A.O. Averianov and A.A. Yarkov

Proceedings of the Zoological Institute RAS, 2010, 314(1): 24–41 · https://doi.org/10.31610/trudyzin/2010.314.1.24

Full text

Abstract

Itilochelys rasstrigin, gen. et sp. nov., a new hard-shelled sea turtle (Cheloniidae sensu lato), is established based on a partial skull, two lower jaws, a humeral bone and cervical vertebrae I–III from the Lower Paleocene of Volgograd Province, Russia. Itilochelys rasstrigin differs from other cheloniids s.l. by the following combination of characters: (1) long skull; (2) short snout; (3) deep cheek emargination; (4) frontal contributing to orbital margin; (5) prefrontal/ postorbital contact absent; (6) long anteroventral process of postorbital; (7) extensive secondary palate; (8) moderate vomer length on triturating surface; (9) deep and narrow midline groove on triturating surface through vomer length; (10) swellings lateral to midline groove present; (11) long lower jaw symphysis; (12) concave lower triturating surface; (13) blunt and shallow symphyseal ridge ending in a triangular elevation; (14) lingual ridges on the lower jaw absent. The new taxon increases diversity of stem-cheloniids and represents the most complete finding of these turtles in Russia.

Key words

Cheloniidae, Paleocene, Russia, Testudines, Volgograd Province

Submitted November 30, 2009 · Accepted March 1, 2010 · Published March 25, 2010

References

Averianov A.O. 2002. Review of Mesozoic and Cenozoic sea turtles from the former USSR. Russian Journal of Herpetology, 9(2): 137–154.

Averianov A.O. and Yarkov A.A. 2000. Some turtles remains from the Cretaceous and Paleogene of Volgograd Region, Russia. Russian Journal of Herpetology, 7(2): 161–166.

Averianov A.O. and Yarkov A.A. 2004. New turtle remains from the Late Cretaceous and Paleogene of Volgograd Region, Russia. Russian Journal of Herpetology, 11(1): 41–50.

Brinkman D., Aquillon-Martinez M.C., De Leon Davila C.A., Jamniczky H., Eberth D.A. and Colbert M. 2009. Euclastes coahuilaensis sp. nov., a basal cheloniid turtle from the late Campanian Cerro del Pueblo Formation of Coahuila State, Mexico. PaleoBios, 28(3): 76–88.

Brinkman D.B., Hart M., Jamniczky H. and Colbert M. 2006. Nichollsemys baieri gen. et sp. nov., a primitive chelonioid turtle from the Late Campanian of North America. Paludicola, 5: 111–124.

Casier E. 1968. Le squelette céphalique de Eochelone brabantica L. Dollo, du Bruxellien (Lutétien inférieur) de Belgique, et sa comparaison avec celui de Chelone mydas Linné. Bulletin de l’Institut Royal des Sciences Naturelles de Belgique, 44: 1–22.

Hirayama R. 1998. Oldest known sea turtle. Nature, 392: 705–708. https://doi.org/10.1038/33669

Hirayama R. 2006. Revision of the Cretaceous and Paleogene sea turtles Catapleura and Dollochelys (Testudines: Cheloniidae). PaleoBios, 26(2): 1–6.

Hirayama R. and Tong H. 2003. Osteopygis (Testudines: Cheloniidae) from the lower Tertiary of the Ouled Abdoun Phosphate basin, Morroco. Palaeontology, 46: 845–856. https://doi.org/10.1111/1475-4983.00322

Joyce W.G., Parham J.F. and Gauthier J.A. 2004. Developing a protocol for the conversion of rank-based taxon names to phylogenetically defined clade names, as exemplified by turtles. Journal of Paleontology, 78: 989–1013. https://doi.org/10.1666/0022-3360(2004)078<0989:DAPFTC>2.0.CO;2

Lynch S.C. and Parham J.F. 2003. The first report of hard-shelled sea turtles (Cheloniidae sensu lato) from the Miocene of California, including a new species (Euclastes hutchisoni) with unusually plesiomorphic characters. PaleoBios, 23: 21–35.

Moody R.T.J. 1974. The taxonomy and morphology of Puppigerus camperi (Gray), an Eocene sea-turtle from northern Europe. Bulletin of the British Museum (Natural History), Geology, 25: 153–186.

Nessov L.A. 1987. The Paleogene sea turtles of southern Kazakhstan and the phylogenetic relationships between the Toxochelyidae and the Cheloniidae. Palaeontologicheskiy Zhurnal, 4: 76–87. [In Russian].

Nessov L.A. and Yarkov A.A. 1989. New Cretaceous-Paleogene birds of the USSR and some remarks on the origin and evolution of the class Aves. Proceedings of the Zoological Institute, Academy of Sciences of the USSR, 197: 78–97. [In Russian].

Owen R. and Bell A. 1849. Reptilia of the Tertiary beds. Part 1. Chelonia. In: Monography of the Fossil Reptilia of the London Clay. Palaeontographical Society, London: 1–76. https://doi.org/10.5962/bhl.title.107491

Parham J.F. and Fastovsky D.E. 1997. The phylogeny of cheloniid sea turtles revisited. Chelonian Conservation and Biology, 2: 548–554.

Tong H. and Hirayama R. 2002. A new species of Tasbacka (Testudines: Cryptodira: Cheloniidae) from the Paleocene of the Ouled Abdoun phosphate basin, Morocco. Neues Jahrbuch für Geologie und Paläontologie, Monatshefte, 5: 277–294. https://doi.org/10.1127/njgpm/2002/2002/277

Tong H. and Hirayama R. 2008. A new species of Argillochelys (Testudines: Cryptodira: Cheloniidae) from the Ouled Abdoun phosphate basin, Morocco. Bulletin de la Societe Géologique de France, 179(6): 623–630. https://doi.org/10.2113/gssgfbull.179.6.623