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The Plectoceratidae is a family of tarphycerids in the suborder Barrandeocerina established as a place for the genus ''Plectoceras''; defined (Sweet 1964) simply as coiled, costate barrandeocerids with subcentral adult siphuncle. According to Sweet, in the original ''Treatise'' Part K,the Plectoceratidae included only ''Plectoceras''. Flower, 1984, however added six other genera, two new and four removed from both the Barrandeoceratidae and Apsidoceratidae. Genera according to Flower, 1984 are: ''Plectoceras'' Hyatt -type genus ''Avilionella'' -removed from Barradeoceratidae ''Bodeiceras'', Flower 1984. added ''Chidleyenoceras'' - removed from the Apsidoceratidae ''Metaplectoceras'', Flower (?synonym for Plectoceras) ''Laureloceras'' Flower 1957, removed from Barrandeoceratidae ''Laurelplecoceras'' Flower 1984 -added According to Flower, 1984, ''Plectoceras'', and therefore the Plectoceratidae, is derived from the Tarphyceratid genus ''Campbelloceras'' while ''Barrandeoceras'', and therefore the Barrandeoceratidae, is derived from ''Centrotarphyceras''. The inclusion of ''Laureloceras'' expands the range of the Plectoceratidae into the Middle Silurian from the Upper Ordovician when it had been with only ''Plectoceras'' ==''References''== *Walter C Sweet, 1964. Nautiloidea-Barrandeocerida; Treatise on Invertebrate Paleontology Part K Mollusca 3. Geological Society of America and University of Kansas Press *Rousseau H. Flower, 1984. ''Bodeiceras''; a New Mohawkian Oxycone, with Revision of the Older Barrandeocerida and Discussion of the Status of the Order. Journal of Paleontology v. 58, no.6, pp 1372–1379, Nov. 1984. 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「Plectoceratidae」の詳細全文を読む スポンサード リンク
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