New Oligocene cyprinid in the central Tibetan Plateau documents the pre-uplift tropical lowlands

Abstract

A new Oligocene-aged genus and species of cyprinid fish, Tchunglinius tchangii, from the Nima Basin in the center of the Tibetan Plateau is described. The new genus is assigned to the subfamily Cyprininae because of its protractile mouth, spoon-shaped pharyngeal teeth, dorsal fin originating anterior to the insertion of the pelvic fin, dorsal fin with four unbranched rays and anal fin with three unbranched rays. This genus differs from other cyprinine genera on the characteristic combination of large head and low body; also, the head length is larger than the body depth. Other differences include the following: the last unbranched ray of both dorsal and anal fin is smooth and articulated; it has an eight-branched ray in the dorsal fin and a five-branched ray in the anal fin; and it has five supraneurals, five hypurals and 33 vertebrae. Tchunglinius tchangii is closely related to recent small-bodied South-Asian cyprinine genera such as Puntius in small body size; therefore, the fossil reflects the Paleogene tropical–subtropical lowland fish fauna present there before the uplift of the Tibetan Plateau.