Genus: Protognathosaurus OLSHEVSKY, 1991
Etymology: Greek, protos, "first" and Greek, sauros, "lizard": First jaw lizard. To replace the preoccupied Protognathus ZHANG, 1988.
= Protognathus ZHANG, in ZHANG & ZENG, 1988 non BASILEWSKY, 1950
Etymology: Greek, protos, "first" and Greek, gnathus, "jaw": “First jaw”.

Species: oxyodon (ZHANG, in ZHANG & ZENG, 1988) OLSHEVSKY, 1991
Etymology: Greek, oxy, "sharp" and Greek, odon, "tooth."
= Protognathus oxyodon ZHANG, in ZHANG & ZENG, 1988

Holotype: CV 00732 (ChM V732)

Locality: Dashanpu (Dashnapu Dinosaur Quarry), lat. 29°5’N, long. 104°50’E, situated 11 km east of Zigong City, 250 km south of Chengdu, Hechuan County, Sichuan Basin, Sichuan (Szechwan) Province, China.

Horizon: Xaishaximiao (Shaximiao) Formation.

Biostratigraphy:

Age: Bathonian-Callovian Stage (DONG & TANG, 1984), Middle-Upper Dogger Epoch, Middle Jurassic.

Note: Bajocian (CHEN et al. 1982), Lower Middle Dogger Epoch, Middle Jurassic.

Material: Dentary missing the posterior end.
Note: The dentary looks very similar to Neimongosaurus.