A new species of the side-necked turtle Foxemys (Pelomedusoides: Bothremydidae) from the Late Cretaceous of Hungary and the historical biogeography of the Bothremydini

Abstract

AbstractThe continental deposits of the Upper Cretaceous (Santonian) Csehbánya Formation of the Bakony Mountains in Hungary yielded abundant remains of a bothremydid side-necked turtle, which are attributed to a new species of the genus Foxemys, Foxemys trabanti. F. trabanti shows strong affinities with the European monophyletic group Foxemydina owing to the absence of pits in the upper and lower triturating surfaces, the exclusion of the jugal from the triturating surface, the separation of the Eustachian tube and the stapes by a narrow fissure, the presence of deep and narrow fossa pterygoidei, the partially closed foramen jugulare posterius and the pentagonal shape of the basisphenoid in ventral view. Among the Foxemydina the bothremydid from Iharkút is more closely related to F. mechinorum than to Polysternon provinciale from the Early Campanian of France, mainly because of the position of the occipital condyle relative to the mandibular condyles of the quadrate. The new remains represent the only record of the Foxemydina outside of Western Europe and provide the earliest known occurrence of this endemic, freshwater group in the former Mediterranean Basin. The historical biogeography of the tribe Bothremydini is investigated and a hypothesis of migration from Africa to North America via the high-latitude Thulean route is put forward.