|
''Hipparionoceras'' is an oncocerid genus from the middle Devonian of Europe, North America, and China that lived around 395 million years ago. The shell of ''Hipparionoceras'' is curved, rapidly expanding, flared toward the aperture. The curvature is endogastric with the ventral side somewhat concave in profile. The siphuncle is subventral, empty, with segments expanded into the short but broad chambers. Septa are close spaced, their curvature shallow. ''Polyelasmoceras'' and ''Macrodomoceras'' are related genera, also from the Middle Devonian. ''Cadoceras'' from the Middle Silurian may be ancestral. ==References== * Walter C. Sweet, 1964. Nautiloidea-Oncocerida. Treatise on Invertebrate Paleontilogy, Part K. Geological Society of America. * (Hipparionoceras ) in Fossilworks Gateway 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「Hipparionoceras」の詳細全文を読む スポンサード リンク
|