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''Permonautilus'' is an extinct nautilid from the Upper Permian of Russia, Named and described by Kruglov in 1933. ''Permonautilus'' is an involute, globular, spinose member of the Lirocertidae which are included in the Clydonautilaceae. Whorl sections are broad, with a rounded venter. The umbilicus in the middle of the shell is deep, from which spine-like processes extend laterally in the mature portion near the aperture. The siphuncle in ''Permonautilus'' is subcentral, the suture, slightly sinuous. Externally, ''Permonautilus'' closely resembles the Pennsylvanian - Lower Permian ''Solenochilus'' and the Upper Mississippian ''Acanthonautilus'', both which belong to the Aipocerataceae; except for the subcentral siphuncle. ==See also== * Nautiloid * * List of nautiloids 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「Permonautilus」の詳細全文を読む スポンサード リンク
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