Dinocephalosaurus (meaning "terrible-headed reptile") is a genus of long necked, aquatic protorosaur that inhabited the Triassic seas of China. The genus contains the type and only known species, D. orientalis, which was named by Li in 2003. Unlike other long-necked protorosaurs (which form a group known as the tanystropheids), "Dinocephalosaurus" convergently evolved a long neck not through elongation of individual cervical vertebrae, but through the addition of cervical vertebrae that each have a moderate length. Like other tanystropheids, however, "Dinocephalosaurus" probably used its long neck to hunt for prey, utilizing a combination of suction, created by the expansion of the throat, and the fang-like teeth of the jaws to ensnare prey. It was probably a marine animal by necessity, as suggested by the poorly-ossified and paddle-like limbs which would have prevented it from going ashore.