,~oiil(igiral Journal o/the /.innem SorieQ (1988), 94: 271-286. With 8 figures The Upper Jurassic selachian Palaeocarcharias de Beaumont (1960) C. J. DUFFIN F.L.S. 113 Shaldon Drive, Morden, Surrey SM4 4BQ Receiaed Nuuember 1987, accepted for publication January 1988 'the terth of Palaeocarcharias stromeri De Beaumont (Kimmcridgian, Upper Jurassic; southern Germany) show linear gradient monognathic heterodonty from high-rusped parasymphyseal teeth to low-crowned posterolaterals. The bifid root has holaulacorhize vasrularization and is surmounted by mesial and distal extensions of the triple-layered roronal enameloid. The crowns lack lateral cusplets, but possess short vertical striations at the base of the central cusp labially and lingually. A collar is developed at the base of the central cusp lingually, and a small node in a similar position labially. It is concluded that Pa/aeocarcharias must represent thc oldest known lamniform. The body form of Palaeocurcharzas is most closely comparable to that of the orectolobiform sharks, but the teeth are lamnoid. Palaeucarcharias is best interprcted as a benthonic stem group lamniform. The lamnifnrms are visualized as arising from orectolohiform ancestors, probably in the middle Jurassic. KEY WORDS:-^ Chondrichthyes - Selachii - Neoselarhii - lamniformes ~ Palaeocarcharias - Upper Jurassic - southrrn Germany. CONTENTS Introduction . . . . . . . . . Systrmatic Palaeontology . . . . . . Grnus Palaeocarcharias de Beaumont ( 1960a) Palaeocarcharias stromeri de Beaumont (1960a) Discussion . . . . . . . . . . The teeth. . . . . . . . . General considerations. . . . . . .4cknowledgements . . . . . . . Rcferrnces. . . . . . . . . . Body form . . . . . . . . . . . . . . . . . . 271 . . . . . . . . . . 272 . . . . . . . . . . 272 . . . . . . . . . . 273 . . . . . . . . . . 278 . . . . . . . . . . 278 . . . . . . . . . . 281 . . . . . . . . . . 284 . . . . . . . . . . 285 . . . . . . . . . . 285 INTRODUCTION The Upper Jurassic fine-grained limestone deposits of the Solnhofen area in southern Germany, and Cerin in France, have long been famous for their wealth of beautifully preserved, whole-bodied, articulated vertebrate fossils. Among3t these are several specimens of cartilaginous fishes. Articulated material of selachians and holocephalans is rare in the fossil record, so the specimens from these localities yield important anatomical data. Work on the taxonomy of Recent sharks is beginning to allow a more informed approach to the study of fossil selachians. Since the bulk of the Upper Jurassic material from continental 1988 The Linncan Society of London 271 0024-4082/88/110271 -t 16 $03.00/0