Miocene and Pliocene amphibians from Hambach (Germany): New evidence for a late Neogene refuge in northwestern Europe

The Hambach lignite mine in northwestern Germany is a renowned fossil locality, which has yielded remains of several vertebrates dated back to the Middle Miocene and the Late Pliocene. Among these is a recently-described and peculiar proteid urodele, Euronecturus grogu, currently known only from the Middle Miocene level in Hambach. Here, we provide detailed descriptions and identifications of the remaining fossil amphibians (both urodeles and anurans) from the Hambach mine, in total identifying at indet., Pelobatidae indet., Hyla sp., Pelophylax sp., Rana sp.) and at least nine Late Ranidae indet.). The high diversity of amphibians in both Miocene and Pliocene levels at Hambach supports a very humid climate persisting in the area for most of the Neogene, possibly originating a refugium for these animals in northwestern Europe that persisted until the Late Pliocene (and possibly even the Early Pleistocene). Urodeles such as Palaeoproteus and Mioproteus and anurans such as Latonia, the palaeobatrachids, and possibly Eopelobates are all significant occurrences in such a northern latitude at the end of the Pliocene, a period when southward withdrawal of thermophilic animals as well as the first effects of a deteriorizing climate ultimately leading to the Quaternary glaciation had already started in the European continent.