''Simbirskiasaurus'' is an extinct genus of
ichthyosaur
Ichthyosaurs (Ancient Greek for "fish lizard" – and ) are large extinct marine reptiles. Ichthyosaurs belong to the order known as Ichthyosauria or Ichthyopterygia ('fish flippers' – a designation introduced by Sir Richard Owen in 1842, altho ...
from the
Early Cretaceous
The Early Cretaceous (geochronological name) or the Lower Cretaceous ( chronostratigraphic name), is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 145 Ma to 100.5 Ma.
Geology
Pr ...
(early
Barremian
The Barremian is an age in the geologic timescale (or a chronostratigraphic stage) between 129.4 ± 1.5 Ma ( million years ago) and 121.4 ± 1.0 Ma). It is a subdivision of the Early Cretaceous Epoch (or Lower Cretaceous Series). It is pre ...
) of
Ulyanovsk Oblast
Ulyanovsk Oblast (russian: Ульяновская область, ''Ul’janovskaja oblast’'') is a federal subject of Russia (an oblast). It is located in the Volga Federal District. Its administrative center is the city of Ulyanovsk. Popula ...
,
Russia
Russia (, , ), or the Russian Federation, is a transcontinental country spanning Eastern Europe and Northern Asia. It is the largest country in the world, with its internationally recognised territory covering , and encompassing one-eigh ...
.
[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
eminiscent of the basal neoichthyosaurian ''Temnodontosaurus platyodon'' (Conybeare, 1822); see Godefroit, 1993]. ''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
nlike in ''Aegirosaurus leptospondylus'' Bardet & Fernández, 2000 and ''Sveltonectes insolitus">Aegirosaurus_leptospondylus.html" ;"title="nlike in ''Aegirosaurus leptospondylus">nlike in ''Aegirosaurus leptospondylus'' Bardet & Fernández, 2000 and ''Sveltonectes insolitus'' (Fischer ''et al''., 2011b)]; pres- ence of a supranarial process of the premaxilla [shared with ''Platypterygius australis'' (McCoy, 1867), see Kear, 2005, and possibly ''Pervushovisaurus, Pervushovisaurus bannovkensis'' (Arkhangelsky, 1998b)]."
[
]
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
* List of ichthyosaurs
This list of ichthyosaurs is a comprehensive listing of all genera that have ever been included in the order Ichthyosauria or the parent clade Ichthyopterygia, excluding purely vernacular terms. The list includes all commonly accepted genera, but ...
* Timeline of ichthyosaur research
This timeline of ichthyosaur research is a chronological listing of events in the history of paleontology focused on the ichthyosauromorphs, a group of secondarily aquatic marine reptiles whose later members superficially resembled dolphins, ...
References
Ophthalmosauridae
Ichthyosauromorph genera
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