Anew species of extinct bullhead sharks, Paracestracion viohli sp. nov. (Neoselachii, Heterodontiformes), from the Upper Jurassic of South Germany

Abstract

The early history of heterodontid sharks is documented mainly by isolated teeth. So far, three different heterodontid genera have been recorded from the Jurassic: Proheterodontus from theMiddle Jurassic of England (and probably Upper Jurassic of France), Paracestracion from the Early to Late Jurassic of England, Belgium and S. Germany, and Heterodontus from the Upper Jurassic of South Germany. Paracestracion is known by isolated teeth in the Early and Middle Jurassic and by articulated skeletons in the Late Jurassic. Recently discovered skeletal remains from the upper Kimmeridgian locality of Schamhaupten, S. Germany, represent a new, hitherto unknown extinct species of Paracestracion, P. viohli sp. nov., which documents further taxonomic diversity of early heterodontids. This new taxon is represented by a subadult individual as indicated by the absence of molariform lateral teeth; it shares with other species of Paracestracion the characteristic holaulacorize cuspidate teeth. It differs from all other species in having ornamented lingual crown faces. Teeth of Proheterodontus differ in a different tooth root vascularisation. Proheterodontus and Paracestracion vanished before or at the Jurassic/ Cretaceous boundary with Heterodontus becoming progressively more diverse in the Cretaceous andCenozoic.