Zob. teĹź:Shimada, K., Everhart, M., Decker, R., & Decker, P. (2010). "A new skeletal remain of the durophagous shark, Ptychodus mortoni, from the Upper Cretaceous of North America: an indication of gigantic body size" Cretaceous Research, 31 (2), 249-254 doi: 10.1016/j.cretres.2009.11.005
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.
http://scienceblogs.com/laelaps/2010/02 ... l-crus.php
rysunek:
http://dibgd.deviantart.com/art/Ptychod ... -155148347