Description of new Pliocene to Early Pleistocene deer (Cervidae, Mammalia) remains from the Siwalik Hills in Pakistan with a discussion on paleobiogeography of cervids from the Indian subcontinent

This article presents a description of new antler remains from five fossiliferous sites (Sardhok, Panjan Sher Shahana, Puran, Jari Kas, and Potha) of the Upper Siwaliks in Pakistan. The systematic study of the antler material revealed the presence of six cervid forms: Metacervocerus punjabiensis, Rucervus sp., Panolia sp., Hyelaphus sp., Praesinomegaceros bakri, and a poorly represented large cervid that shows a certain affinity with “Eucladoceros sp.” from the Early Pleistocene of Kuruksai (Tajikistan). The remains of Panolia represent the earliest known paleontological record of this cervid lineage. Unlike Metacervocerus and Rucervus that have had phylogenetically closely related counterparts in east and north of the Alpine-Himalayan mountain belt, the evolution of Panolia took place in the Indian subcontinent. The entry of Panolia lineage into the Indian subcontinent marks its phylogenetic split from the main Cervus/Rusa evolutionary branch. The earliest dispersal events of cervids into the Indian subcontinent was preceded by the late Miocene evolutionary radiation and ecological diversification of the subfamily Cervinae in Southeastern Asia. Praesinomegaceros and Metacervocerus most probably entered the Indian subcontinent via Central Asia. Possibly, this is also the case of “Eucladoceros sp.” from Kuruksai (Tajikistan). The dispersal ways of Panolia and Rucervus remain unclear. The dispersals of small-sized cervids (Muntiacus and Hyelaphus) into the Indian subcontinent was triggered by the establishment of the 100-ky glaciation cycle during the Middle Pleistocene: the sea level dropped during glacial peaks and opened to them the dispersal route from Sundaland in the South.