New Hoplitomeryx Leinders, 1984 remains from the late Miocene of Gargano (Apulia, Italy)

Natural selection in isolated environments led to the positive selection of species bearing an extraordinary array of morphological traits and a very high grade of endemism. The unbalanced mammal assemblage found in the Upper Miocene karst infillings of the Gargano Peninsula (southern Italy), and especially the intriguing ruminant Hoplitomeryx, is one of the best examples of fast, isolated evolution. Hoplitomeryx exhibits a peculiar combination of craniodental and postcranial characters, some of which are unique among the other ruminant families. For this reason, its phylogenetic position is still puzzling and far from being clarified. Thus, every contribution to a more comprehensive knowledge of the genus is crucial to better understand the evolutionary process that led to such an advanced and peculiarly adapted ruminant. Here we report newly discovered dentognathic remains from the Gargano Peninsula, which are attributed to six different species of Hoplitomeryx on the basis of morphological and metrical evidence. Overall, our results show that the different species of Hoplitomeryx are clearly distinguished from each other on the basis of the dental morphology, which accounts for the high intraspecific and interspecific variability of the genus. In addition, we describe for the first time a new type of “Muntiacus-like” upper canine, with no-spiralization, more robust shaped and with more rounded anterior margin than the upper canines previously reported for Hoplitomeryx.