| Xainzanoceras | |
|---|---|
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Cephalopoda |
| Subclass: | Nautiloidea |
| Order: | † Tarphycerida |
| Family: | † Lituitidae |
| Genus: | † Xainzanoceras Chen, 1987 |
Xainzanoceras is a genus of nautiloid cephalopods from the Upper Ordovician of China, assigned to the tarphyceratid family Lituitidae. The type, Xainzanoceras xaizangense Chen resembles the ophidioceratid genus Ophioceras . The shell is evolute, discoidal, serpenticonic; whorl section rounded, covered with thick, straight, close spaced, radial ribs that curve slightly forward at the ventral margin where they become quickly reduced or lost.
