The oldest known European Neogene girdled lizard fauna (Squamata, Cordylidae), with comments on Early Miocene immigration of African taxa

This paper reports on the first record of cordylid lizards from the locality of Merkur-North. The fossil history of girdled lizards is very poorly known and this group was rare during the Lower Miocene in Europe. The fossils described herein come from grey calcareous marls at the base of the so-called “Main Brown Coal Seam”. These marls are interpreted as reworked volcanic ash and the sediments are considered as early Miocene in age and are precisely equated with the MN 3a zone. For this reason, the cordylid fauna from this locality is older than previously described Miocene material and it represents the oldest known Neogene cordylids in Europe. The material of the dentary is very similar to that of Palaeocordylus bohemicus Roček, 1984, described from the younger locality of Dolnice near Cheb. The intramandibular septum of the dentary described herein, lying ventromedially from the alveolar canal, has a free posterolateral portion. It represents the first report of this structure in cordylids. The maxilla is only fragmentarily preserved. The size difference between the maxillary and dentary elements, the number of teeth and, especially their morphology evokes the possibility of two different taxa. Unfortunately, it is impossible to decide on the basis of such limited material if both finds represent independent forms or only extreme forms of the same taxon.