A. Yu. Berezin (2018)Â
Cranial bones of the plesiosaur Abyssosaurus nataliae Berezin from the Lower Cretaceous of center of the Russian platform.
Paleontological Journal 52(3): 105-118 (Russian edition)
DOI:Â 10.7868 / S0031031X18030133
Cranial bones of the plesiosaurus Abyssosaurus nataliae Berezin, 2011 from the Upper Hauterivian (Lower Cretaceous) of Chuvashia are described. It differs from other known Cryptoclididae in the obvious pedomorphic characters in the skull structure. The skull is strongly hypertrophic; the visceral part is shortened relative to its large occipital region; the orbits are enlarged, the lower jaw is narrow. The jugal is well developed, included vertically, and borders most of the posterior orbital wall. This skull structure is evidence of deepwater mode of life. The species diagnosis is revised.