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Simbirskiasaurus and Pervushovisaurus (Cretaceous ichthyosaurs) reassessed

Ben Creisler

A new online paper:

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
Zoological Journal of the Linnean Society (advance online publication)
DOI: 10.1111/zoj.12158

The ichthyosaur fossil record is interspersed by several hiatuses,
notably during the Cretaceous. This hampers our understanding of the
evolution and extinction of this group of marine reptiles during the
last 50 million years of its history. Several Cretaceous ichthyosaur
taxa named in the past have subsequently been dismissed and referred
to the highly inclusive taxon Platypterygius, a trend that has created
the impression of low Cretaceous ichthyosaur diversity. Here, we
describe the cranial osteology, reassess the stratigraphic age, and
evaluate the taxonomy and phylogenetic relationships of two Cretaceous
ichthyosaurs from western Russia: Simbirskiasaurus birjukovi from the
early Barremian and Pervushovisaurus bannovkensis from the middle
Cenomanian, both formerly regarded as nomina dubia, and allocated to
Platypterygius sp. and Platypterygius campylodon, respectively. We
show that Simbirskiasaurus birjukovi and Pervushovisaurus bannovkensis
are valid platypterygiine ophthalmosaurids, notably characterized by a
peculiar narial aperture. The cranial anatomy and phylogenetic
relationships of these taxa illuminate the evolution of narial
aperture anatomy in Cretaceous ichthyosaurs, clarify the phylogenetic
relationships among platypterygiines, and provide further arguments
for a thorough revision of Platypterygius.