Poterioceratidae is a family of

nautiloid Nautiloids are a group of marine cephalopods ( Mollusca) which originated in the Late Cambrian and are represented today by the living ''Nautilus'' and ''Allonautilus''. Fossil nautiloids are diverse and speciose, with over 2,500 recorded species ...

cephalopods included in the

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 ...

that lived during the period from the Early

Devonian The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, whe ...

to the Early

Carboniferous The Carboniferous ( ) is a geologic period and system of the Paleozoic that spans 60 million years from the end of the Devonian Period million years ago ( Mya), to the beginning of the Permian Period, million years ago. The name ''Carbonifero ...

( Mississippian). Members of the Poterioceratidae are distinguished by a subcircular to compressed exogastric shell (curved upwardly so as the lower side, the venter, is convex viewed from the side) that has no hyponomic sinus and a central to subcentral

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

composed of subquadrate to nummuloidal segments in which the septal necks are more strongly curved on the upper, or dorsal side. This is opposite from the

Karoceratidae Karoceratidae is a family of nautiloids within the order Oncocerida The Oncocerida comprise a diverse group of generally small nautiloid cephalopods known from the Middle Ordovician to the Mississippian (early Carboniferous; one possible memb ...

in which siphuncle segments are inflated ventrally but straight dorsally. Some poterioceratid genera have actinosiphonate structures or annular deposits within the siphuncle. In others it is empty. The origin of the Poterioceratidae is undetermined but may have their origin in some

Silurian The Silurian ( ) is a geologic period and system spanning 24.6 million years from the end of the Ordovician Period, at million years ago ( Mya), to the beginning of the Devonian Period, Mya. The Silurian is the shortest period of the Paleozo ...

member of the

Acleistoceratidae The Acleistoceratidae is a family of oncocerids that contains genera characterized by depressed (or rarely compressed) exogastric brevicones and cyrtocones (Sweet, 1964 K398) that range from the Middle Silurian to the Middle Devonian. The siphu ...

or perhaps even in some

Ordovician The Ordovician ( ) is a geologic period and System (geology), system, the second of six periods of the Paleozoic Era (geology), Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start ...

oncoceratid through an unknown Silurian genus.

References

* 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 Nautiloidea, Geological Society of America and University of Kansas Press; Teichert and Moore, (eds)
Poterioceratidae -Paleodb
12/11/2010 {{Taxonbar, from=Q16988446 Oncocerida Early Devonian first appearances Mississippian extinctions Prehistoric nautiloid families