Yanhecerida

Yanhecerida Temporal range:
Scientific classification Edit this classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Cephalopoda
Subclass:	Nautiloidea
Superorder:	†Plectronoceratoidea
Order:	†Yanhecerida Chen et al., 1979
Genera
Yanheceratidae Aetheloxoceras Archendoceras Oonendoceras Yanheceras

Yanhecerida is a small order of Late Cambrian (mid-Stage 10) nautiloid cephalopods. They were similar to the more diverse Plectronocerida and Ellesmerocerida, with short shells, closely spaced septa, and diaphragms (partitions) within the siphuncle. Their most distinctive trait is the conical shape of the diaphragms, similar to the endocones which characterize the later nautiloid order Endocerida. While some authors have argued that Yanhecerida should be lumped into Ellesmerocerida, a phylogenetic analysis has maintained that Yanhecerida is a valid clade of early cephalopods closely related to a paraphyletic Ellesmerocerida (and by extension all post-Cambian cephalopods).