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.
Protognathosaurus is known only from a fragmentary lower jaw,
holotype CV 00732 (= ChM V732) found in a layer of the
Shaximiao Formation dating from the
Bathonian-
Callovian. The fragment consists of the front left
dentary and shows eighteen tooth positions, some still containing sharp replacement teeth, after which the genus was named. Most researchers consider
Protognathosaurus to be a
nomen dubium. ==References==