Pervushovisaurus

Pervushovisaurus is a genus of platypterygiine ichthyosaur from the Late Cretaceous (Cenomanian) of the Saratov region in western Russia, the La Penthiève Beds of France and the Cambridge area of the UK.

Pervushovisaurus
Temporal range: Cenomanian
P. campylodon snout fragment, the lectotype specimen of the species
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: †Ichthyosauria
Family: †Ophthalmosauridae
Subfamily: †Platypterygiinae
Genus: †Pervushovisaurus
Arkhangel'skii, 1998
Species
  • †P. bannovkensis Arkhangel'skii, 1998 (Type)
  • †P. campylodon Fischer, 2016
Synonyms
  • Ichthyosaurus campylodon Carter, 1846
  • Pervushovisaurus bgnnovkensis Arkhangel'skii, 1998 (sic)
  • "Pervushovisaurus" hercynicus
  • "Pervushovisaurus" kiprianoffi

History
Rostra assigned to P. campylodon

It was originally described as a subgenus of Platypterygius,[1] but later work showed that it was sufficiently distinct from the type species of Platypterygius, P. platydactylus, to be elevated to full generic rank.[2] The type species of Pervushovisaurus, P. bannovkensis, is known only from the holotype, SSU 104a/24, a partial skull.[3] In 2016, an additional species of Platypterygius from England and France, P. campylodon, was also referred to Pervushovisaurus after previously being allied with Ichthyosaurus in 1846.[4][5][6] A previous Russian species of Platypterygius, "P." kiprianoffi, was also assigned to P. campylodon.[7][8][9]

A specimen of P. campylodon was found in the La Penthiève Beds of France and was described in 1882 by Henri Émile Sauvage.[10]

Description
Life restoration of P. campylodon

Pervushovisaurus was a medium-sized ichthyosaur measuring 5.8 metres (19 ft) long.[1] Fishcer (2016) gave the emended diagnosis of Pervushovisaurus as follows, based on that of Fischer et al. (2014):[2][6] "Platypterygiine ophthalmosaurid characterized by the following autapomorphies [...]: presence of foramina along the ventral premaxillary–maxillary suture; presence of a semi-oval foramen on the lateral surface of the premaxilla, anteroventral to the external naris; presence of lateral ridges on the maxilla; presence of wide supranarial ‘wing’ of the nasal (a similar structure, although much smaller, is present in ‘Platypterygius’ australis and Acamptonectes densus) (see Kear, 2005; Fischer et al., 2012, respectively); robust splenial markedly protruding from the external surface of the mandible; root with quadrangular cross-section, with the cementum forming prominent 90° angles.

Pervushovisaurus is also characterized by the following unique combination of features: secondarily closed naris surrounded by foramina (as in ‘Platypterygius’ sachicarum and ‘Platypterygius’ australis (see Paramo, 1997; Kear, 2005, respectively), and in Simbirskiasaurus birjukovi, although the ‘anterior’ naris is still present in this taxon (Maisch & Matzke, 2000; Fischer et al., 2014a)); elongated anterior process of the maxilla, reaching anteriorly the level of the nasal (unlike in Aegirosaurus leptospondylus, Sveltonectes insolitus and Muiscasaurus catheti) (Bardet & Fernández, 2000; Fischer et al., 2011a; Maxwell et al., 2015, respectively); rostrum straight (unlike in ‘Platypterygius’ americanus, ‘Platypterygius’ sachicarum, ‘Platypterygius’ australis and possibly Muiscasaurus catheti, where it is slightly curved anteroventrally Romer, 1968; Paramo, 1997; Kear, 2005; Maxwell et al., 2015, respectively); straight, non-recurved tooth crowns (unlike in Sveltonectes insolitus, Muiscasaurus catheti) (Fischer et al., 2011a; Maxwell et al., 2015, respectively)."

References
  1. Arkhangel’sky, M. S. (1998). "On the Ichthyosaurian Genus Platypterygius". Paleontological Journal. 32 (6): 611–615.
  2. Fischer, Valentin; Arkhangelsky, Maxim S.; Naish, Darren; Stenshin, Ilya M.; Uspensky, Gleb N.; Godefroit, Pascal (2014). "Simbirskiasaurus and Pervushovisaurus reassessed: implications for the taxonomy and cranial osteology of Cretaceous platypterygiine ichthyosaurs". Zoological Journal of the Linnean Society. 171 (4): 822–841. doi:10.1111/zoj.12158.
  3. Storrs, G. W., M. S. Arkhangel'skii and V. M. Efimov. (2000). Mesozoic marine reptiles of Russia and other former Soviet republics. pages 187-210 In Benton, M. J., M. A. Shiskin, D. M. Unwin and E. N. Kurochkin, (eds.), The Age of Dinosaurs in Russia and Mongolia, Cambridge University Press, Cambridge.
  4. Carter, J. (1846a). Notice of the jaws of an Ichthyosaurus from the chalk in the neighbourhood of Cambridge. Reports of The British Association for The Advancement of Science.
  5. Carter, J. (1846b) On the occurrence of a new species of Ichthyosaurus in the Chalk. London Geological Journal. 1846b;1:7–9.
  6. Fischer, V. (2016). "Taxonomy of Platypterygius campylodon and the diversity of the last ichthyosaurs". PeerJ. 4: e2604. doi:10.7717/peerj.2604. PMC 5075704. PMID 27781178.
  7. "Mesozoic marine reptiles of Russia and other former Soviet Republics". The Age of Dinosaurs in Russia and Mongolia. Cambridge, UK: Cambridge University Press. 2000. pp. 187–210.
  8. McGowan, C.; Motani, R. (2003). "Ichthyopterygia". Handbook of Paleoherpetology. Munich, Germany. 8: 175.
  9. Zammit, M. (2012). "Cretaceous Ichthyosaurs: Dwindling Diversity, or the Empire Strikes Back?". Geosciences. 2 (2): 187–210. doi:10.3390/geosciences2020011.
  10. Sauvage, H.-É., (1882), "Recherches sur les reptiles trouvés dans le Gault de l'est du bassin de Paris", Mémoires de la Société Géologique de France, série 3 2(4): 1-42
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