Zetoceras

Zetoceras Temporal range: Sinemurian–Bajocian PreꞒ Ꞓ O S D C P T J K Pg N
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Cephalopoda
Subclass:	†Ammonoidea
Order:	†Ammonitida
Family:	†Phylloceratidae
Subfamily:	†Phylloceratinae
Genus:	†Zetoceras Kovacs, 1939

Zetoceras is an extinct ammonoid cephalopod genus from the suborder Phylloceratina that lived during the Early and Middle Jurassic in what is now Europe, and is included in the (family) Phylloceratidae.[1]

Zetoceras has a compressed involute shell with a very small umbilicus. The suture is phylloid, as for the suborder, with tall primary sutural elements. Saddles commonly have tetraphyllic endings.[1] Zetoceras is considered by some (Wright et al, 1996) to be a subgenus of Phylloceras. The two are very similar except that the saddle endings in Phylloceras split in three rather than in four as in Zetoceras.

References

1. Arkell, W.J.; Kummel, B.; Wright, C.W. (1957). Mesozoic Ammonoidea. Treatise on Invertebrate Paleontology, Part L, Mollusca 4. Lawrence, Kansas: Geological Society of America and University of Kansas Press.

• Wright, Calloman, and Howarth. 1996; Cretaceous Ammonoidea. Treatise on Invertebrate Paleontology L(4)
• The Paleobiology Database Zetoceras entry