Simbirskiasaurus is an extinct genus of Ichthyosauria from the Early Cretaceous (early Barremian) of Ulyanovsk Oblast, Russia.[Valentin Fischer, Maxim S. Arkhangelsky, Darren Naish, Ilya M. Stenshin, Gleb N. Uspensky and Pascal Godefroit (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. http://onlinelibrary.wiley.com/doi/10.1111/zoj.12158/abstract] Its type specimen is YKM 65119, a fragmentary skull and vertebral column.[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.]
Description
Fischer
et al. give the diagnosis of
Simbirskiasaurus as follows: "Platypterygiine ophthalmosaurid characterized by the following autapomorphies: external naris divided by a nasomaxillary pillar; posterior opening of the narial complex with anteroposteriorly constricted dorsal extension; deeply interdigitating prefrontal–lacrimal suture reminiscent.
Simbirskiasaurus birjukovi is also characterized by the following unique combination of features: subnarial process of the premaxilla reaches the posterior margin of the external naris (shared with
Cryopterygius kristiansenae Druckenmiller
et al., 2012); elongated anterior process of the maxilla, reaching anteriorly the level of the nasal unlike; pres- ence of a supranarial process of the premaxilla shared."
[
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Phylogeny
The following cladogram shows a possible phylogenetic position of Simbirskiasaurus in Ophthalmosauridae according to the analysis performed by Zverkov and Jacobs (2020).
See also
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List of ichthyosaurs
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Timeline of ichthyosaur research
