| 词条 | Cycloceras |
| 释义 |
| name = Cycloceras | fossil_range = Ordovician-Permian | image = | image_caption = | regnum = Animalia | phylum = Mollusca | classis = Cephalopoda | subclassis = Nautiloidea | ordo = Orthocerida | ordo_authority = | familia = | familia_authority = | genus = Cycloceras | genus_authority= McCoy (1844) | subdivision_ranks = Species | subdivision = }}Cycloceras is an extinct nautiloid cephalopod genus from the Carboniferous of Western Europe, (Ireland and Scotland) of unknown affinity with the orthocerida (Sweet 1964 in) [1] TaxonomyCycloceras was named by McCoy (1844 and assigned to the Michelinoceratida by Flower (1962)and to the Orthocerida by Sweet in Teichert et al. (1964);[2]Cycloceras is possibly a member of the Cycloceratidae and may be synonymous with Perigrammoceras Foerste MorphologyThe type species of Cycloceras, C. annularis, is based in an internal mold of a body chamber on which the position of the siphuncle is indiscernible (Sweet 1964,) Species referred to Cycloceras are annulated, subcylindrical orthocones with no longitudinal ornamentation . Fig 186, p K258 Teichert et al. (1964) shows Cycloceras as narrow, gently expanding, annulated othocone with a narrow subcentral siphuncle. Annuli (circular transverse bands or costae) are thick and close spaced, giving a corrugated appearance. References1. ^C. Teichert et al 1964. Treatise on Invertebrate Paleontology K(3)Nautiloidea:1-519 {{Portal|Paleontology}}{{Taxonbar|from=Q5198683}}2. ^PaleoBiology Database:Cycloceras,basic info 5 : Prehistoric nautiloid genera|Carboniferous cephalopods|Prehistoric animals of Europe|Paleozoic life of Ontario|Paleozoic life of Nunavut |
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