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| image = Macrocephalites_rotundus_01.JPG | regnum = Animalia | phylum = Mollusca | classis = Cephalopoda | subclassis = Ammonoidea | ordo = Ammonitida | superfamilia = Stephanocerataceae | familia = Macrocephalitidae | genus = ''Macrocephalites'' | genus_authority = Zittel, 1884 }} ''Macrocephalites'' is a genus of the stephanoceratacean ammonite family Macrocephalitidae, diagnostic of the Callovian stage of the Middle Jurassic. Three subgenera, ''Dolikephalites'', ''Kamptokephalites'', and ''Pleurocephalite'' are recognized in addition to ''Macrocephalites'' itself, with ''Indocephalites'' tentatively included as the fourth. ==Diagnosis ''Macrocephalites'' s.s.== ''Macrocephalites'' itself has a strongly ribbed, involute, subglobose to discoidal shell with a somewhat small open umbilicus, compressed whorl section, higher than wide, and rounded venter. Early whorls are more strongly ribbed than later, which become smoother, ending with a smooth body chamber. Primary ribs, which emanate radially from the umbilicus, bifurcate and sometimes trifurcate mid flank and cross the venter uninterrupted. Shells grew to be large, even gigantic. Distribution is widespread. 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「Macrocephalites」の詳細全文を読む スポンサード リンク
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