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Liroceras
''Liroceras'' is a genus of nautiloid cephalopod. It is the type genus of the clydonautiliacean family, Liroceratidae Liroceratidae is an extinct family of nautilids, shelled marine molluscs, belonging to the Clydonautiloidea, consisting of generally smooth, involute, nautiliconic forms with a small umbilicus. The whorl section is usually depressed and broad ..., and is characterized by a rapidly expanding, subglobular, nautiliconic shell with a reniform whorl section, small umbilicus, essentially straight sutures, and a siphuncle with a variable but not marginal position.Bernhard Kummel, 1964. Nautiloidea-Nautilida; '' Treatise on Invertebrate Paleontology'', Part K. Geol Soc of America and Univ of Kansas Press, R. C. Moore (ed) — Liroceratidae K444–K447. ''Liroceras'' has a temporal range from the Mississippian to the Permian period, the longest of the Liroceratidae. It has been found in North America, Europe, China and the East Indies. A similar genus, '' Condr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Condraoceras
''Condraoceras'' is a genus of Liroceratidae, liroceratids from the Pennsylvanian of North America and Lower Permian of Europe with a compressed, involute, nautiliconic shell; subcircular whorl section; small umbilicus with a rounded shoulder; suture with shallow ventral and lateral lobes; and narrow subcentral siphuncle. ''Liroceras'', from the same time and type of the family, differs in having a reniform whorl section and essentially straight sutures at maturity. ''Peripetoceras'', another related genus, has a flattened venter, slight ventral and lateral lobes in the suture, and a siphuncle offset dorsally from the center. ''References'' * Bernhard Kummel, 1964. Nautiloidea -Nautilida; Treatise on Invertebrate Paleontology, Part K. Geol Soc of America and Univ of Kansas press, R.C. Moore (ed) -- Liroceratidae K444 -K447. Prehistoric nautiloid genera Pennsylvanian first appearances Lopingian genus extinctions {{Paleo-nautiloid-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |