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''Scaphites'' (Greek ''skafh'', "a boat or anything dug or scooped out") is a genus of extinct cephalopod belonging to the family of heteromorph ammonites (suborder Ancyloceratina). They were a widespread genus that thrived during the Cretaceous period. ''Scaphites'' generally have a chambered, boat-shaped shell. The initial part (juvenile stage) of the shell is generally more or less involute (tightly-coiled) and compressed, giving no hint of the heteromorphic shell form yet to come. The terminal part (adult stage) is much shorter, erect, and bends over the older shell like a hook. They have transverse, branching ribs with tubercles (small bumps) along the venter. Reconstructions of the body within the shell can be made to portray ''Scaphites'' as either a benthic (bottom-dwelling) or planktonic animal, depending on where the center of gravity is located. Since useful fossils of the soft-body parts of cephalopods are highly rare, little is known about how this animal actually fit into its shell and lived its life. Because ''Scaphites'' and its relatives in Superfamily Scaphitaceae are restricted to certain divisions of the Cretaceous (''ca.'' 144 to 66.4 million years ago), they are useful in some areas as an index fossil. A notable example is the Late Cretaceous Western Interior Seaway in North America, in which several endemic lineages of scaphite species evolved and now serve as the basis for a highly resolved regional biostratigraphy. == Species == * ''Scaphites binneyi'' † Reeside 1927 * ''Scaphites carlilensis'' † Morrow 1935 * ''Scaphites depressus'' † Reeside 1927 * ''Scaphites ferronensis'' † Cobban, 1951 * ''Scaphites frontierensis'' † Cobban 1951 * ''Scaphites hippocrepis'' † (DeKay) 1827 * ''Scaphites impendicostatus'' † Cobban 1951 * ''Scaphites leei'' † Reeside 1927 * ''Scaphites nanus'' † Reeside 1927 * ''Scaphites nodosus'' † * ''Scaphites obliquus'' † J. Sowerby 1813 * ''Scaphites preventricosus'' † Cobban 1951 * ''Scaphites tetonensis'' † Cobban 1951 * ''Scaphites uintensis'' † Cobban 1951 * ''Scaphites warreni'' † Meek and Hayden 1860 * ''Scaphites whitfieldi'' † Cobban 1951 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「Scaphites」の詳細全文を読む スポンサード リンク
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