Sinohelicoprion

Sinohelicoprion (meaning "Chinese spiral saw" or "Chinese Helicoprion") is an extinct genus of helicoprinid eugeneodontid fish that lived during the late Permian and possibly the Early Triassic, from 254 to 251 million years ago.^[1][2]

Sinohelicoprion Temporal range: 254–251 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓ Changhsingian-Induan?
Tooth whorl (IVPP V4752.2) of S. qomolangma, Paleozoological Museum of China
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Chondrichthyes
Subclass:	Holocephali
Order:	†Eugeneodontida
Family:	†Helicoprionidae
Genus:	†Sinohelicoprion Liu & Chang, 1963
Species
S. changhsingensis Liu & Chang, 1963 (type) S. macrodontus Lei, 1983 S. qomolangma Zhang, 1974

Comparison of S. changhsingensis and Helicoprion sp.

It was first named and classified by H. T. Liu and M. N. Chang in 1963.^[3][4]