Palaeobatrachids are an extinct group of aquatic frogs. They occurred from the Late Cretaceous to the Pleistocene, only in Europe with the exception of one questionable species recorded in the late Maastrichtian Lance Formation of Wyoming and a second possible occurrence in the early Paleocene of Montana.Here, we describe about ninety isolated palaeobatrachid bones well-preserved in three-dimensions (maxillae, surangulars, vertebrae, urostyles, ilia and humeri) from the early Paleocene locality of Hainin (Belgium), which is the reference-level MP1-5 of the mammalian biochronological scale for the European Paleogene. These remains are clearly attributable to a single species of palaeobatrachid that presents the following typical characters: a surangular with a coronoid process bearing muscle scars on dorsal surface; a bicondylar sacro-urostylar articulation; an urostyle with a low neural crest and lacking transversal processes; a humerus with the humeral condyle in the alignment of the bone, epicondyles similar in size; an ilium presenting a large acetabular area, a short and posteriorly oriented pars ascendens, an elongate tuber superius, an horizontal depression on the inner surface of the iliac shaft and lacking the dorsal crest and the pars descendens; and procoelous vertebrae with typical crescent-like cotyle and condyle. The four known palaeobatrachid genera have all been recently synonymized with Palaeobatrachus for which at least seven species are now recognized. The taxon from Hainin differs from most Palaeobatrachus species in the absence of cubital fossa on the humerus, the presence of diapophyses on the first vertebra, and the maxilla that presents a higher number of tooth positions. It is thus referred to a new Palaeobatrachus species or a new genus depending of the definition of the genus Palaeobatrachus. Prior to this study, fragmentary remains of palaeobatrachids had been identified in the Campanian of France and Spain and in the Late Paleocene of France. The early Paleocene species from Hainin is therefore the earliest formally described species from Europe. This abstract is a contribution to the project BR/121/A3/PALEURAFRICA funded by the Belgian Science Policy Office.

Peer Review, Impact Factor, RBINS Collection(s)

Paleontology