|
| image = | regnum = Animalia | phylum = Mollusca | classis = Cephalopoda | subclassis = Ammonoidea | ordo = Ceratitida | superfamilia = Megaphyllitoidea | familia = Parapopanoceratidae | genus = ''Parapopanoceras'' | genus_authority = Haug,1894 | subdivision_ranks = Species | subdivision = * ''P. asseretoi'' * ''P. dzeginense'' * ''P. inconstans'' * ''P. malmgreni'' * ''P. paniculatum'' * ''P. torelli'' * ''P. wapii'' | synonyms = ''Dienerites'' named by Mojsisovics,1902 }} ''Parapopanoceras'' is a ceratitid ammonite with a small, smooth, very involute and moderately globose shell that lived during the middle Triassic. ''Parapopanoceras'' normally has 6 to 7 whorls in its phragmocone, seldom as much as nine, with a body chamber 1-1.5 whorls in length. The suture is ceratitic with phylloid (leaf-like) saddles and subdivided lobes. The siphuncle begins at a central or subcentral position and in most species becomes ventral at the end of the second whorl. In all species septal nacks are short retrochoanitic (point adapically) in the first whorl, are transitory in the second whorl, and become prochoanitic (point adorally) in the third whorl and thereafter. Closely related ''Stenopopanoceras'' differs in that its siphuncle starts off ventral. ''Parapopanoceras'' was named by Haug in 1994. The type species is ''Popanoceras verneuili'' Mojsisovics 1886. Related genera include ''Amphipopanoceras'' and ''Stenopopanoceras''. ==Distribution== Fossils have been found in Svalbard, Jan Mayen, British Columbia, the Russian Federation, and possibly Papua New Guinea. 〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Parapopanoceras」の詳細全文を読む スポンサード リンク
|