Middle Miocene toothed whale with Platanista-like teeth from the Vienna Basin (Western Carpathians, Slovakia)

A fragmentary odontocete (toothed whale) skull, found in the Late Badenian (Middle Miocene, Early Serravallian, 13-12.7 Ma) marine deposits of the locality Rohoznik-Konopiska, Slovakia, on the eastern margin of the Vienna Basin, north-western part of the Central Paratethys Sea, includes fragments of the rostrum and mandible with a series of 70 teeth. This specimen is referred here to the platanistid subfamily Pomatodelphininae, based on the long and narrow dorsoventrally flattened rostrum and mandible, the strong curvature, the ornament, and the size range of the teeth. Tooth sections show only one complete postnatal growth layer, indicating a very Young individual. This record extends the presence of pomatodelphinines in the Central Paratethys into the late Middle Miocene. The peculiar morphology of the feeding apparatus, namely the elongated jaws and the tong and interlocking anterior teeth, suggests that this taxon and related species were feeding in a way similar to the fish-eating relict Recent platanistid Platanista (Ganges and Indus River dolphins). The local geological and palaeogeographic contexts, especially the proximity of the palaeo-Danube delta, further support the frequent association of platanistids with deltaic to freshwater deposits. Nevertheless, the geographic distribution of fossil and Recent platanistids implies that at least some species were able to cross strictly marine regions.