Miocene Bovidae (Mammalia) of the Siwaliks, Part 1: Hypsodontinae and Bovinae.

Alan Gentry, Nikos Solounias , John C. Barry and S. M. Raza

The fluvial sediments of the Siwaliks in northern Pakistan preserve an exceptional geologic and paleontological record encompassing parts of the Oligocene and all of the Miocene and Pliocene. The sediments, which can be thousands of meters thick, have abundant vertebrate and invertebrate fossils from hundreds of different levels. Fossils were first discovered in the Siwaliks in 1832 and there are important collections of them in the Museum of the Geological Survey of India as well as in various European, British, and American museums. Renewed collecting has now added over 10,000 bovid fossils to a new collection held by the Geological Survey of Pakistan. The fossils include rare skulls and many isolated horn cores, as well as teeth and postcranials. Here we discuss material belonging to the hypsodontinae, boselaphini, and bovini. We recognize four hypsodontine and twenty-two bovine species, plus one species of uncertain subfamilial placement. Nineteen of the twenty-seven have previously been named, while another five have cranial material suitable for defining a new species. Two species, referred to as  ?Hypsodontinae sp. and Bovidae sp. 1, are distinctive but left unnamed. We are also uncertain about how distinctive what we refer to as Selenoportax aff. vexillarius is from Selenoportax vexillarius. Boselaphinines predominate in the fossil collections, both in terms of number of species and number of specimens. Most of the boselaphine genera are endemic to the Siwaliks, as are the hypsodontine Palaeohypsodontus and the possible bovini Pachyportax. The predominance of boselaphines together with the number of endemic taxa gives the Siwalik bovid fauna a distinctive aspect and collectively comprise the best-known Miocene record of the subfamily.