A new genus and species of Pliohyracidae (Hyracoidea, Mammalia) from the Pliocene of Jradzor, Armenia

Hyracoidea is a group of afrotheres that is today represented by three extant genera, but its fossil diversity is much greater. While most recent palaeontological studies have focused on documenting the earliest radiation of the group (Eocene–Oligocene), fewer works have attempted to highlight the later diversification (Miocene–Pleistocene) of large hypsodont forms that dispersed across the Eurasian continent. Herein we describe a newly discovered, well-preserved skull from the late Pliocene (3.3 ± 0.03 Ma) locality of Jradzor (Armenia), attributed to a new representative of late-diverging Eurasian Pliohyracidae, assigned to a new genus and species, which is notably characterised by a dental formula lacking an upper canine. The range of the new form is so far restricted to the latest Pliocene (early MN16) in Armenia. Comparison with previously described pliohyracids and a phylogenetic analysis including, for the first time, a substantial sample of Eurasian Neogene Pliohyracidae support the monophyly of this family under its least inclusive definition. The analyses support Titanohyracidae as the sister group of pliohyracids. We therefore tentatively provide the first phylogenetic definition of the family Pliohyracidae. Except for the unstable position of the incomplete and enigmatic Hengduanshanhyrax, relationships within the family are consistent with a biogeographical history involving dispersal of pliohyracids in Eurasia from Africa. Higher-level relationships, notably with Procaviidae and Palaeogene genera, remain to be clarified in future studies aimed at accurately delineating the diversity of both modern and fossil hyracoids.