''Conostichoceras'' is a genus of exogastric, breviconic oncocerids included in the family

Nothoceratidae Nothoceratidae is a family of nautiloid cephalopods in the orthoceratoid order Oncocerida in which shells are exogastrically or endogastrically breviconic, planospiral, or torticonic; often with a constricted or visored aperture; and a siphun ...

, known from the Middle Devonian of central Europe and Upper Devonian of Australia.Sweet, W.C. 1964. Nautiloidea-Oncocerida

Treatise on Invertebrate Paleontology The ''Treatise on Invertebrate Paleontology'' (or ''TIP'') published by the Geological Society of America and the University of Kansas Press, is a definitive multi-authored work of some 50 volumes, written by more than 300 paleontologists, and co ...

part K. It probably lived on and swum above the sea floor.

Morphology

''Conostichoceras'', named by Foeste, 1926, produced a depressed exogastric breviconic shell with short, wide chambers and large living chamber, similar to ''

Blakeoceras ''Blakeoceras'' is a nautiloid cephalopod from the Oncocerida family Nothoceratidae with a curved shell that lived in shallow seas from the Silurian to the Middle Devonian in what has become Europe. The shell of ''Blakeoceras'' is moderatel ...

'' and '' Turnoceras'' but differing details especially of the siphuncle. The siphuncle is ventral; nummuloidal in the adapical half of the phragmocone but with concave profiles in the adoral half, and is actinosiphonate. The sides of the living chamber in the adult converge slightly on the aperture.

Taxonomy

In its broader taxonomy ''Conostichoceras'' belongs to a group of nautiloid cephalopods known as the

Nautilitoidea The Nautilitoidea is a superorder within the subclass Nautiloidea, comprising the phylogenetically related Nautilida, Oncocerida, and Tarphycerida. The superorder has its roots in the Bassleroceratidae, the ancestral family of the Tarphycerida, ...

, a superorder that includes the orders

Oncocerida The Oncocerida comprise a diverse group of generally small nautiloid cephalopods known from the Middle Ordovician to the Mississippian (early Carboniferous; one possible member is known from the Early Permian), in which the connecting rings are t ...

Tarphycerida The Tarphycerida were the first of the coiled cephalopods, found in marine sediments from the Lower Ordovician (middle and upper Canad) to the Middle Devonian. Some, such as '' Aphetoceras'' and '' Estonioceras'', are loosely coiled and gyroconi ...

, and

Nautilida The Nautilida constitute a large and diverse order of generally coiled nautiloid cephalopods that began in the mid Paleozoic and continues to the present with a single family, the Nautilidae which includes two genera, ''Nautilus'' and ''Allonauti ...

.Wade, M. 1988. Nautiloids and their descendants: cephalopod classification in 1986. Memoir 44, pp 15-25; New Mexico Bureau of Mines and Mineral Resources, Socorro, NM The family

to which it belongs is one of 16 included in the Oncocerida.

References

Prehistoric nautiloid genera Oncocerida {{paleo-Nautiloidea-stub

Morphology

Taxonomy

See also

References