''Litoceras'' is a trocholitid (Tarphycerida) genus that has been found in the Lower and Middle

Ordovician The Ordovician ( ) is a geologic period and System (geology), system, the second of six periods of the Paleozoic Era (geology), Era, and the second of twelve periods of the Phanerozoic Eon (geology), Eon. The Ordovician spans 41.6 million years f ...

Newfoundland Newfoundland and Labrador is the easternmost province of Canada, in the country's Atlantic region. The province comprises the island of Newfoundland and the continental region of Labrador, having a total size of . As of 2025 the population ...

. Whorls in ''Litoceras'' have a broadly rounded cross section with its width greater than its height. Litoceras somewhat resembles the tarphyceratid ''Pionoceras'' from the same time, except for 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 ...

being dorsal and in the center.

Species

Species within the genera ''Litoceras'' include: * '' Litoceras calciferum'' (Billings, 1865) * '' Litoceras versutum'' (Billings, 1865) * '' Litoceras whiteavsi'' Hyatt, 1894

References

*Furnish, W.M and Glenister, Brian F (1964); Nautiloidea -Tarphycerida in the

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 L, Nautiloidea, Geological Society of America and Univ of Kansas press. {{Taxonbar, from=Q6648643 Prehistoric nautiloid genera Early Ordovician first appearances Middle Ordovician extinctions Paleozoic life of Newfoundland and Labrador Tarphycerida