†<i>Tingitanius tenuimandibulus,</i>a new platyrhinid batoid from the Turonian (Cretaceous) of Morocco and the cretaceous radiation of the Platyrhinidae

Abstract

ABSTRACT An exceptionally well-preserved specimen of a batoid from the Turonian (Late Cretaceous) of Morocco has been named as †Tingitanius tenuimandibulus, sp. nov. The fossil has been identified as a member of the Platyrhinidae and represents the oldest known example of a thornback ray. Mechanical and acid preparation of the ventral surface has revealed the general body form of the specimen and permitted teeth and three morphotypes of dermal denticles to be extracted. Computed tomographic (CT) scanning of the chondrocranium and thoracic region has allowed the detailed study of the skeletal elements concealed within the rock. The phylogenetic position of the new specimen and implications for the phylogenetic positions of the 'rhinobatoids' are discussed. †Britobatos, gen. nov., is erected to accommodate †Raja primarmata which is here shown to be a sister taxon to the Platyrhinidae including †Tingitanius. It is likely that reassessment of isolated batoid teeth from the Cretaceous and Paleogene will confirm the former importance of the Platyrhinidae. ACKNOWLEDGMENTS We thank the UTCT for scanning this fossil and W. Holloway for rendering the skeleton in Avizo, as well as two reviewers for their constructive comments and contributions. We also thank M. Richter and Z. Johanson at the NHMUK for their help with access to and curation of fossil specimens. From UCL we thank J. Davy for his help with the SEM work. We are particularly indebted to B. Tahiri who brought the specimen to our attention and let us purchase it for a very reasonable price. Funding for this research was provided in part by the Banks Fellowship for Paleontology, the Ohio University Heritage College of Osteopathic Medicine Research & Scholarly Affairs Committee, and the Society of Vertebrate Paleontology Predoctoral Fellowship. Handling editor: Matt Friedman