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Prodiplocynodon
''Prodiplocynodon'' is an extinct genus of basal crocodyloid crocodylian. It is the only crocodyloid known from the Cretaceous and existed during the Maastrichtian stage. The only species of ''Prodiplocynodon'' is the type species ''P. langi'' from the Lance Formation of Wyoming, known only from a single holotype skull lacking the lower jaw.
The skull was collected by the American Museum Expedition of 1892 from exposures near the Cheyenne River in Niobrara County. It was described by Charles C. Mook of the American Museum of Natural History in 1941.〔 The generic name means "before ''Diplocynodon''" because Mook saw close similarities between the holotype skull and that of the alligatoroid ''Diplocynodon'' from the Eocene of Europe.
==Description==
Most of the cranial sutures that outline individual bones of the skull are not visible in the holotype, and are often obscured by cracks. However, the overall shape of ''Prodiplocynodon'' is similar to that of basal alligatoroids.〔 Many of the features seen in ''Prodiplocynodon'' are common among eusuchians. The skull is short and triangular, being around in length. The orbits, or eye sockets, are quite large and subtriangular. The teeth are short and somewhat sharp, and in comparison to modern crocodiles show little variation. The orbits face directly upwards, but this may have been the result of slight compression in the holotype skull. The external nasal aperture, the opening for the nostrils, is very large. There is a constriction at the point of contact between the premaxilla and maxilla which would have been an area of reception for a large mandibular tooth. In ''Prodiplocynodon'', the constriction is not deep, being intermediate between that of ''Alligator'' and ''Crocodylus''.〔
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
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