|
''Cartersoceras'' is a nautiloid cephalopod genus placed in the Orthocerid family Baltoceratidae, established by Rousseau Flower (1964), for species formally included in part in ''Murrayoceras'', and in part in "''Sacotoceras''". This group is typical of ''Murrayoceras'' in all features except that the siphuncle segments are convex in outline.〔Rousseau H Flower, (1964). The nautiloid order Ellesmeroceratida (Cephalopoda). New Mexico Bureau of Mines and Mineral Resources Memoir 12.〕 It is known from the Middle Ordovician of the eastern United States. The type species ''Cartersoceras shideliri'' Flower from the Carters Limestone, Beach Grove, Tennessee, shows a ventral rod secreted calcite in the siphuncle and thick, fibrous connecting rings which are not layered as in early Ellesmerocerida.〔 ''C.noveboracense'', originally referred to ''Murrayoceras'', from the Amsterdam Limestone of New York, known from a weathered portion of the phragmocone, shows part of the siphuncle filled with calcite, determined to represent a secreted ventral rod.〔 The ventral rod and unlayered connecting rings were used to place this genus in the rod-bearing Baltoceratidae. Frey (1995)〔R. C. Frey. 1995. Middle and Upper Ordovician nautiloid cephalopods of the Cincinnati Arch region of Kentucky, Indiana, and Ohio. U.S. Geological Survey Professional Paper 1066P:1-126 ()〕 retained ''Cartersoceras'' in the Baltoceratidae while Kroger et al. (2007) 〔B. Kröger, et al . 2007. Early orthoceratoid cephalopods from the Argentine Precordillera (Lower-Middle Ordovician). Journal of Paleontology 81(6):1266-1283 ()〕 included it in the Sactorthoceratidae, in spite of the ventral rod. ''Carteroceras'' is probably closely related to genera like ''Rhabdiferoceras'' and ''Murrayoceras'' and more distantly to such as ''Tajaroceras'' and ''Veneficoceras'' ==''References''== 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「Cartersoceras」の詳細全文を読む スポンサード リンク
|