|
The Hoplitidae is a family of Cretaceous ammonites that lived during the middle of the period from the late Aptian to the Cenomanian. They are part of the superfamily Hoplitaceae. Members of the Hoplitidae are typically evolute, with inner whorls exposed, although some are more involute, and are commonly stout and strongly ribbed, with pronounced tubercles. The Hoplitidae are thought to be derived from the U Aptian -M Albian ''Uligella'' of the Desmoceratidae, or some related form and have been divided into three subfamilies. ==Subfamlies== Cleoniceratidae: high-whorled, compressed hoplitids with narrowly arched to acute venters and sigmoid to falcoid ribs at least on the inner whorls and in some cases strong umbilical tubercles. Genera include ''Aioloceras'', ''Anadesmoceras'', and ''Cleoniceras''. Hoplitinae: generally discoidal and strongly ribbed forms that make up most of the family. Ribs come off of umbilical tubercles and may be branched, looped, or zigzagged. Venters, the outer rims, may be rounded or flat and in some cases concave and may be a smooth band running along the middle. Includes genera such as ''Euhoplites'', ''Hoplites'', ''Pluerohoplites , and ''Sonneratia''. Gastrohoplitidae: mostly boreal hoplitids, similar in general appearance to the other two subfamilies, represented by ''Gastrohoplites'' 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「Hoplitidae」の詳細全文を読む スポンサード リンク
|