''Jiagouceras'' is a genus of early primitive

cephalopod A cephalopod is any member of the molluscan Taxonomic rank, class Cephalopoda (Greek language, Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral symm ...

s from the

Upper Cambrian The Furongian is the fourth and final epoch and series of the Cambrian. It lasted from to million years ago. It succeeds the Miaolingian series of the Cambrian and precedes the Lower Ordovician Tremadocian Stage. It is subdivided into three sta ...

China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

, assigned to the

Plectronoceratidae Plectronocerida is a primitive order from which subsequent Cephalopoda, cephalopod orders are ultimately derived.Curt Teichert, 1988. Main Features of Cephalopod Evolution. The Mollusca Vol. 12 Paleontology and Neontology of Cephalopds; Academic ...

. The shell is small, nearly straight with a slight endogastric curvature and compressed cross section. The

siphuncle The siphuncle is a strand of biological tissue, tissue passing longitudinally through the mollusc shell, shell of a cephalopod mollusc. Only cephalopods with chambered shells have siphuncles, such as the extinct ammonites and belemnites, and the li ...

is close to the ventral margin, with segments expanded into the chambers. ''Jiagouceras'' is found in the Wanwankou member of the Fengshan formation (Early, Middle and Upper Trempealeauan) in northern

Anhui Anhui is an inland Provinces of China, province located in East China. Its provincial capital and largest city is Hefei. The province is located across the basins of the Yangtze and Huai rivers, bordering Jiangsu and Zhejiang to the east, Jiang ...

, China. It is similar to '' Paraplectronoceras'' except for having more strongly expanded siphuncular segments and less concave septa.

References

* Chen Jun-yuan et al., 197
Late Cambrian Cephalopods of North China -- Plectronocerida, Protactinocerida (Ord Nov) and Yanhecerida (Ord Nov)
* * Teicher, C. 1988. Main Feature of Cephalopod Evolution. ''in'' The Mollusca, volume 12, Paleontology and Neontology of Cephalopods. Clark and Trueman (eds). Academic Press.
Paleobiology DB - Jiagouceras
{{Taxonbar, from=Q6191424 Prehistoric nautiloid genera