Archovember 2025 Day 2
Protorosaur Dinocephalosaurus orientalis, of Middle Triassic, China!
Second on our Archovember list this year is the bizarre Middle Triassic protorosaur, Dinocephalosaurus orientalis. Like their relatives, the tanystropheids, Dinocephalosaurus had a long neck with fang-like teeth used for catching fish. But, unlike the tanystropheids, its neck was not lengthened through the elongation of cervical vertebrae, but rather the addition of at least 27 individual neck vertebrae, giving it much higher flexibility. Also unlike the tanystropheids, it had paddle-like flippers which would have given it a purely aquatic lifestyle. Dinocephalosaurus’ long neck would have allowed it to sneak up on potential prey without its larger body being detected. One Dinocephalosaurus specimen was preserved with an embryo that suggests it gave live birth, making it the first known viviparous archosauromorph, (aside from possibly metriorhynchids).
Dinocephalosaurus orientalis was first described from the Upper Member of the Guanling Formation, with additional specimens discovered in the Luoping locality. Inhabiting the Middle Triassic seas of China, it would have lived alongside icthyosaurs such as Mixosaurus and Xinminosaurus, a wide variety of early sauropterygians like Keichousaurus, Wumengosaurus, Dianopachysaurus, Nothosaurus, and Placodus, and other marine reptiles like Sinosaurosphargis.
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