[en] Ophthalmosaurinae is a recently recognized clade of derived ichthyosaurs (marine reptiles) ranging from the Bajocian (Middle Jurassic) to the late Albian (late Early Cretaceous). Whereas the Middle-Late Jurassic ophthalmosaurine Ophthalmosaurus is often regarded as a hyperspecialized deep diver, very little is known about the anatomy, evolutionary history, and ecology of Cretaceous ophthalmosaurines because of the scarcity of the fossils and the lack of well-preserved skull material. Here, we describe the skull of a new basal ophthalmosaurine ichthyosaur, Leninia stellans gen. et sp. nov., from the lower Aptian of western Russia, and compare the ocular characteristics of ophthalmosaurids. Leninia is recovered as a basal ophthalmosaurine; it possesses unique traits such as star-shaped frontal–parietal sutures as well as features previously thought to be unique to Ophthalmosaurus such as a supratemporal–stapes contact. A large sclerotic aperture – significantly bigger than in platypterygiine ophthalmosaurids and similar to that of the largest-eyed modern animals (giant and colossal squids) – and reduced dentition appear widespread within ophthalmosaurines. This conservatism suggests ophthalmosaurine ophthalmosaurids occupied similar ecological niche(s) throughout their long evolutionary history.
Disciplines :
Earth sciences & physical geography Zoology
Author, co-author :
Fischer, Valentin ; Université de Liège - ULiège > Département de géologie > Paléontologie animale et humaine
Arkhangelsky, Maxim
Uspensky, Gleb
Stenshin, Ilya
Godefroit, Pascal
Language :
English
Title :
A new Lower Cretaceous ichthyosaur from Russia reveals skull shape conservatism within Ophthalmosaurinae
Publication date :
2014
Journal title :
Geological Magazine
ISSN :
0016-7568
Publisher :
Cambridge University Press, New York, United States - New York
Volume :
151
Issue :
1
Pages :
60-70
Peer reviewed :
Peer Reviewed verified by ORBi
Funders :
F.R.S.-FNRS - Fonds de la Recherche Scientifique [BE]
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