Yanhecerida

Yanhecerida is a small order of Late Cambrian (mid-Stage 10)[1] 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.[2][3] While some authors have argued that Yanhecerida should be lumped into Ellesmerocerida,[4] 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).[3]

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