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Tornoceratatina is one of two suborders included in the Goniatitida, characterized by generally involute, subdiscoidal shells and by sutures in which the ventral ones are undivided. Sutural lobes increase in number during the course of life of the individual, typically developed from the internal and external saddles. The siphuncle is prochoanitic, with septal necks projecting forward. Derivation is from the Anarcestida in the middle Devonian. ==References== * Miller, Furnish, and Schindewolf, 1957. Paleozoic Ammonoidea. Treastise on Invertebrate Paleontology, Part L. Geological Society of America. * Tornoceratina in (Goniat ) on line, Mar. 5, 2015 * (The Paleobiology Database ) Oct.1, 2007 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「Tornoceratina」の詳細全文を読む スポンサード リンク
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