First evidence of ichnopathologies in Rhinoceripeda tasnadyi tracks from the Miocene of Hungary

• We describe the first ichnological record of malformation in rhinocerotid, showing a split digit III hoof. • It’s a very rare occurrence also in the modern record, therefore no precise cause can be identified. • The malformation happened long before the impression as no gait variations are recorded. • Rhinocerotid bones from Eocene and Miocene show less malformation than modern ones, making this finding of higher impact. Despite a vast record, ichnological evidence of malformed or injured animals is extremely rare. During the re-examination of slabs collected from the Ipolytarnóc tracksite (Early Miocene, North Hungary) and housed at the Supervisory Authority for Regulatory Affairs, three “atypical” tracks were detected along the same trackway. They belong to the ichnotaxon Rhinoceripeda tasnadyi , attributed to a medium- to large-sized “hornless” Miocene rhinocerotids. The hoof of the left digit III appears to be split, rather than oval, at approximatively half of its width, giving an almost tetradactyl appearance to the footprints. The deformation due to overprinting is excluded because of the number of tracks showing the same variation. This injury/malformation could be identified as the atypical tracks belong to a trackway where the opposite impression is preserved and due to the large number of accessible R. tasnadyi footprints. These account for a wide range of the standard variability of the morphology at Ipolytarnóc. If the track record was limited, or when the atypical tracks do not belong to a trackway, it would not be possible to recognise those differences as ichnopathologies and, as a result, a different trackmaker would have been assessed, or a wrong ichnotaxonomical diagnosis would have been attributed.