''Kionoceras'' is an extinct
nautiloid cephalopod genus included in the
orthocerid
Orthocerida is an order of extinct Orthoceratoid cephalopods also known as the Michelinocerida that lived from the Early Ordovician () possibly to the Late Triassic (). A fossil found in the Caucasus suggests they may even have survived until ...
family
Kionoceratidae
Kionoceratidae is a family in the Orthocerida, proposed by Hyatt in 1900 for genera characterized by prominent ornamentation in the form of longitudinal ribs, ridges, or lirae, or combinations thereof, sometimes with similar transverse ornament ...
with scattered worldwide distribution from the Middle
Ordovician to the Lower
Permian. Kionoceratids are orthocerids with prominent longitudinal ornamentation on their shells, sometimes augmented by secondary transverse ornamentation. Orthocerids are, of course, prehistoric nautiloides with generally straight and elongate shells, mostly with central or subcentral
siphuncles. (Sweet 1964)
''Kionoceras'' is characterized by long, slender to rapidly expanding, shells with prominent longitudinal ribs separated by concave interspaces and, often, less conspicuous longitudinal and transverse lirae and striae. The siphuncle is central or subcentral, generally orthochoanitic; empty in Silurian type-species and in most from the Ordovician, but with annulosiphonate deposits in some from the Silurian and later.
''Kionoceras'' is found in North America, Europe, Asia, and Australia. The type-species ''Kionocers doricum'' comes from the Middle Silurian of Central Europe
See also
*
Nautiloid
**
List of nautiloids
This list of nautiloids is a comprehensive listing of all genera that have ever been included in the subclass Nautiloidea, excluding purely vernacular terms. The list includes all commonly accepted genera, but also genera that are now considered in ...
References
* Sweet, W.C. 1964: Nautiloidea - Orthocerida;
Treatise on Invertebrate Paleontology Part K, Mollusca 3; Teichert and Moore (eds).
* Sepkoski, J.J. Jr. 2002. A compendium of fossil marine animal genera
Sepkoski's Online Genus Database (CEPHALOPODA)
{{Taxonbar, from=Q6414517
Nautiloids
Middle Ordovician first appearances
Cisuralian genus extinctions
Paleozoic molluscs of North America
Paleozoic life of Ontario
Paleozoic life of Manitoba
Paleozoic life of New Brunswick
Paleozoic life of the Northwest Territories
Paleozoic life of Nunavut
Paleozoic life of Quebec