Observations on Triassic ichthyosaurs. Part XII. A new Early Triassic ichthyosaur genus from Spitzbergen

Quasianosteosaurus vikinghoegdai n. g. n. sp. is described on the basis of an incomplete skull from the Spathian Sticky Keep Formation of Mount Viking, Sassendalen. It is the oldest reasonably complete ichthyosaur cranium known so far, and indicates an animal which is unusually large, as compared to the majority of other known Early Triassic ichthyosaurs, with an estimated skull length of at least 50 cm. The skull compares most closely to Parvinatator wapitiensis among known ichthyosaurs, but is still so distinct, particularly in the arrangement of the bones of the cheek region, that the genus must be referred to a new family., Quasianosteosauridae n. fam. Quasianosteosaurus represents the sister-taxon of the Hueneosauria, being slightly more derived than Parvinatator and the Grippiidae. Early Triassic ichthyosaurs were already much more diversified than demonstrated by the fossil record so far; their initial radiation must have been very rapid.