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''Watinoceras'' is an acanthoceratid genus (Cephalopoda, Ammonoidea) that lived during the early Turonian stage of the Late Cretaceous. Early whorls are compressed, finely ribbed with inner and outer ventrolateral and siphonal tubercles as in ''Neocardioceras'', but siphonal row is soon lost. Later the venter may be concave between rows of vantrolateral clavi or rounded with ribs passing over in chevrons. Ornament usually becomes coarser with age. Derivation is from ''Neocardioceras''. It (''Watinoceras'') and ''Mammites'' gave rise to the other genera in the subfamily. Some classifications include ''Watinoceras'' in the subfamily Acanthoceratinae instead. Other species include ''Watinoceras coloradoense'', ''W. reesidei'', and ''W. thompsonense''. The first occurrence of the species Watinoceras devonense marks the beginning of the Turonian.〔(【引用サイトリンク】website=https://engineering.purdue.edu/Stratigraphy/gssp/detail.php?periodid=42&top_parentid=35 )〕 ==References== * W.J. Arkell, et al., 1957. Mesozoic Ammonoidea, Treatise on Invertebrate Paleonotology Pat L Mollusca 4. Geological Society of America and University of Kansas Press. * W.J. Kennedy, et al., 1999. Lower Turonian (Upper Cretaceous) Watinoceras devonense Zone ammonite fauna in Colorado, USA. USGS Publications Warehouse -Citations View. () * (''Wutinoceras'' ) in Fossilworks 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「Watinoceras」の詳細全文を読む スポンサード リンク
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