A new skeletal remain of the durophagous shark, Ptychodus mortoni, from the Upper Cretaceous of North America: an indication of gigantic body size

Ptychodus mortoni Mantell is a Late Cretaceous shark that possessed pavement-like tooth plates that were used to feed on hard-shelled macroinvertebrates (durophagy). Here, we describe a new specimen of P. mortoni from the Fort Hays Limestone Member of the Niobrara Chalk in Kansas, USA, that consists of associated teeth, placoid scales, and a portion of the right upper jaw. Although the specimen is fragmentary, this fossil supports the previously proposed contention that P. mortoni was a gigantic animal that likely reached at least 10 m in total body length with an estimated jaw length of nearly 1 m.