Protognathosaurus

Protognathosaurus (meaning "early jaw lizard") is a genus of herbivorous sauropod dinosaur from the Middle Jurassic Lower Shaximiao Formation in Sichuan, present-day China.

==History== In 1988 Zhang Yihun named and described the type species Protognathus oxyodon. The generic name was derived from Greek πρῶτος, protos, "first", and γνάθος, gnathos, "jaw". The specific name is derived from Greek ὀξύς, oxys, "sharp", and ὀδών, odon, "tooth". However, the generic name was preoccupied, already in use, by a genus of carabid beetle, Protognathus (Basilewsky, 1950) which is considered a synonym of Pseudognathaphanus (Schauberger, 1932). The species was therefore renamed into the combinatio nova Protognathosaurus oxyodon by George Olshevsky in 1991.