''Metacoceras'' is a nautilitoid cephalopod from the Upper

Carboniferous The Carboniferous ( ) is a Geologic time scale, geologic period and System (stratigraphy), system of the Paleozoic era (geology), era that spans 60 million years, from the end of the Devonian Period Ma (million years ago) to the beginning of the ...

(

Pennsylvanian Pennsylvanian may refer to: * A person or thing from Pennsylvania * Pennsylvanian (geology) The Pennsylvanian ( , also known as Upper Carboniferous or Late Carboniferous) is, on the International Commission on Stratigraphy, ICS geologic timesc ...

) and

Permian The Permian ( ) is a geologic period and System (stratigraphy), stratigraphic system which spans 47 million years, from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.902 Mya. It is the s ...

, the shell of which is moderately evolute with a subquadrate whorl section, bearing nodes on the ventral or umbilical shoulders or both, but otherwise smooth. 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 small, subcentral and orthochoanitic. The suture has shallow ventral and lateral lobes but no dorsal or annular lobe. Metacoceras_fossil_from_Iran

''Matacoceras'', named by Hyatt, 1883, is a genus in the nautilid superfamily Tainocerataceae. Its distribution is cosmopolitan.

''References''

External links

*Bernhard Kummel, 1964. Nautiloidea-Nautilida.

Treatise on Invertebrate Paleontology The ''Treatise on Invertebrate Paleontology,'' published from 1953–2007 by the Geological Society of America and the University of Kansas, then 2009–present by the University of Kansas Paleontological Institute, is a definitive multi-authore ...

, Part K. Geological Soc. of America and University of Kansas press. Teichert and Moore (eds) {{Taxonbar, from=Q6822422 Nautiloids Pennsylvanian first appearances Permian genus extinctions