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''Sturia'' is a ceratitid ammonoid from the Lower Triassic with an ammonitic suture. ''Sturia'' produced a robust, laterally compressed, high whorled, involute shell; whorls strongly embracing. the surface is without ribs or constructions but does have sharp spiral lines. the suture is ammonitic, deeply digitate; lobes and saddles narrowly V-shaped overall. The ventral lobe is divided, 1st lateral lobe is larger than the second, which is followed by a series of auxiliary lobes decreasing in size toward the umbilicus. J.P Smith, 1932, included ''Sturia'' in the Thalassoceratidae, but only tentatively. The American Treatise on Invertebrate Paleontology, Part L, 1957, includes ''Sturia'' in the Ptychitidae, along with such genera as ''Ptychites'', ''Discoptychites'', ''Aristoptychites'', and ''Parasturia''. ''Sturia'' is now included in the Sturiidae, established by Kipsarova. 1958, for genera such as already mentioned ''Sturia'', ''Parasturia'', and ''Discoptychites'', notably distinct from genera retained in the Ptychitidae, like ''Ptychites''. ==References== *Arkell, W.J. et al., 1957. Mesozoic Ammonoidea. Treatise on Invertebrate Paleontology Part L. Geological Society and University of Kansas Press. *Smith, J.P. 1932. Lower Triassic Ammonoids of North America. US Geological Survey Professional Paper 167. * (''Sturia'' ) 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「Sturia」の詳細全文を読む スポンサード リンク
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