Stability in Higher Level Taxonomy of Miocene Bovid Faunas of the Siwaliks

Ann. Zool. Fennici 51: 49–56 ISSN 0003-455X (print), ISSN 1797-2450 (online) Helsinki 7 April 2014 © Finnish Zoological and Botanical Publishing Board 2014 Stability in higher level taxonomy of Miocene bovid faunas of the Siwaliks Alan W. Gentry1,*, Nikos Solounias2 & John C. Barry3 1) c/o Earth Sciences Department, Natural History Museum, Cromwell Road, London SW7 5BD, UK (*corresponding author’s e-mail: [email protected]) 2) New York College of Osteopathic Medicine, Department of Anatomy, Old Westbury, New York 11568-8000, USA 3) Department of Human Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA Received 21 May 2013, final version received 26 Sep. 2013, accepted 21Aug. 2013 Gentry, A. W., Solounias, N. & Barry, J. C. 2014: Stability in higher level taxonomy of Miocene bovid faunas of the Siwaliks. — Ann. Zool. Fennici 51: 49–56. The bovid faunas of the Siwaliks (Pakistan) show little change in structure or higher level taxonomy through much of the Middle and Late Miocene. Species of Bovinae and Antilopinae are abundant and Caprinae very rare. Introduction the basis of biostratigraphy (Barry et al. 2002, Behrensmeyer & Tauxe 1982). The Neogene vertebrate faunas of the Siwaliks The Siwaliks succession has long been of Pakistan and northern India are contained in arranged in a set of time-transgressive forma- a thick sequence of fluvial sediments associ- tions. That part of the sequence covering the ated with the Himalayan orogeny. They have Miocene is given by Barry et al. (2002: table 1) attracted scientific attention since the first half as: of the 19th century and research is still ongoing. One such collaborative project in recent years • Dhok Pathan Formation 10.1 to ~3.5 Ma was undertaken by the Geological Survey of • Nagri Formation 11.2 to 9.0 Ma Pakistan and the Pakistan Museum of Natural • Chinji Formation 14.2 to 11.2 Ma History, together with Harvard University and • Kamlial/Murree Formation 18.3 to 14.2 Ma the University of Arizona. The crucial contri- bution of this study has been to establish a The age estimates used in this paper are chronology for a great number of fossiliferous based on the magnetic timescale of Cande and localities in the Potwar Plateau based on palaeo- Kent (1995), later refined by Ogg and Smith magnetic measurements. To create this chrono- (2004). The Middle Miocene starts at a little logical framework 36 stratigraphic sections have over 16.0 Ma and the Late Miocene close to 11.0 been measured and correlated to each other and Ma (Steininger 1999: figs. 1.1–1.2, Harzhauser the Geomagnetic Polarity Time Scale and then & Piller 2007: fig. 1). The appearance of hip- correlated locally to an additional 11 sections by parionine horses in Old World terrestrial faunas using lithological marker horizons believed to is a good indication that the changeover to the be isochronous. No correlations were made on Late Miocene has happened, and in the Siwa- 50 Gentry et al. • ANN. ZOOL. FENNICI Vol. 51 liks these horses are inferred to have appeared spond with a scientific taxonomic category. In after 10.9 Ma (Barry et al. 2002). The end of the Eurasia tiny bovid-like dental remains are known Miocene is dated at 5.3 Ma, but our bovid record from the early Oligocene of Mongolia onwards does not extend so late as that, partly arising (Dmitrieva 2002), and the first definite Bovidae from uncertainties about the dating of localities. with horns appear in Eurasia and Africa at least The short statement to be made in this paper two million years before the transition from the concerns the Miocene Bovidae so abundantly Early to the Middle Miocene. More information preserved in the Siwaliks from the Chinji Forma- on fossil Bovidae and references thereon can be tion upward. It will not discuss their taphonomy found in Bibi et al. (2009) and Gentry (2010). and palaeoecology. Bovidae are a family of rumi- nant mammals containing the cattle, sheep, goats and antelopes, all characterised by horns in which Bovidae of the Siwaliks Miocene the hollow horny sheaths are mounted on bony cores and in which neither sheath nor core is An outline classification of bovids is shown in branched or seasonally shed. The English word Table 1. The Hypsodontinae probably originated “antelope” is used for bovids not native to Europe from among the earlier bovid-like forms in east- or not domesticated there, and does not corre- ern Asia. They were already present in our area Table 1. A possible classification of the subfamilies and tribes of Bovidae. Miocene Siwaliks groups underlined and in boldface. Extinct groups marked with obelisks. Vertical lines to the left indicate four possible higher hierarchical groupings: (A) the early Hypsodontinae, (B) Boselaphini and allied tribes, (C) a cluster centred around Antilopini, (D) the caprine–alcelaphine group. Subfamily Antilopinae is usually regarded as the cladistic sister group to subfamily Bovinae, in which case all ranks in D would need downgrading. Sources: Gentry (1992), Gatesy et al. (1997), Vrba and Schaller (2000), Hernández-Fernández and Vrba (2005), Marcot (2007), Hassanin et al. (2012), Bärmann et al. (2013). The placings of Criotherium, Oiocerini and Tethytragus are speculative. A │Subfamily †HYPSODONTINAE │ †HYPSODONTINI — Middle Miocene, perhaps diphyletic to other bovids. B │Subfamily BOVINAE: │ BOSELAPHINI — nilgai and four-horned antelope. │ TRAGELAPHINI — kudu, bushbuck group. African. │ BOVINI — cattle, buffalo. C │Subfamily ANTILOPINAE: │ CEPHALOPHINI — duikers. African. │ NEOTRAGINI — dik dik, steinbok and other small antelopes. African. │ ANTILOPINI — impala, blackbuck, saiga antelope, gazelles. │ †Criotherium — Late Miocene, plus †Palaeoreas, coming from Antilopini. │ PELEINI — Vaal rhebok, Pelea capreolus. African │ REDUNCINI — waterbuck and reedbuck group, perhaps originating from near │ the ancestry of Pelea. │ †OIOCERINI — Late Miocene, includes †Urmiatherium. D │Subfamily HIPPOTRAGINAE: │ HIPPOTRAGINI — roan, sable antelope, oryx, addax. │ ALCELAPHINI — hartebeest and wildebeest group. This and the preceding tribe │ arose near the base of the Caprinae. │?Subfamily of its own: │ †Tethytragus — Middle Miocene. Relationship with Oiocerini, Hippotragini, │ Pantholops or Caprinae still to be decided. │?Subfamily of its own: │ Pantholops — chiru, one Asian genus near the origin of Caprinae. │ │Subfamily CAPRINAE: │ RUPICAPRINI or NAEMORHEDINI — chamois, serow, goral. │ Budorcas — takin, not in the Ovibovini. │ OVIBOVINI — muskox. │ CAPRINI — goats, but tribe for sheep still to be decided. ANN. ZOOL. FENNICI Vol. 51 • Stability in higher level taxonomy of Miocene bovids of the Siwaliks 51 of southern Asia before the end of the Oligocene onwards, may be present in the Siwaliks but with and perhaps penetrated as far as Saudi Arabia by rather few fossils. Its subfamily or tribal affilia- the Early Miocene. They acquired horn cores in tion has not been decided other than that it is not the Middle Miocene perhaps in parallel to other a boselaphine. Other extinct genera in Miocene bovids, and spread widely before disappearing faunas are similarly unplaced taxonomically. later in the Middle Miocene. The suggestion that Finally Caprinae are a mainly Eurasian group but they could be an Old World branch from the same with only one certain occurrence in the Siwaliks. stem as Antilocapridae, and diphyletic from other Table 2 lists the species of Miocene Siwa- (true) bovids, needs further investigation. liks bovids as we have identified them from Within the Bovinae, the two species of Bose- horn cores and, when possible, from teeth. At laphini today are relicts but boselaphines were first sight the list looks like an incredibly rich prominent in Siwalik Middle and Late Miocene fauna, but this is misleading. A few entries are faunas and also present in Africa, Europe and for early species predating the Chinji Formation, eastern Asia. Bovini descended from Boselap- for which numbers of fossils are low and iden- hini and the earliest known bovine comes from tifications still uncertain. Some entries are for the Late Miocene of the Siwaliks, judged by the single occurrences or for a few specimens with a appearance there of large, high-crowned (hyp- very short time range. The bracketed entries are sodont) teeth with complicated occlusal surfaces time successive and may be ancestor-descendant (Bibi 2007). Tragelaphini, despite their phyletic pairs or sequences. Six species or possible line- links to Boselaphini, are an African group and ages of Middle Miocene bovids from 14.0 Ma have not been found in the Siwaliks. onwards and five Late Miocene ones are com- In the Antilopinae, the Neotragini look like a moner and better substantiated (more than ten paraphyletic assemblage of small African ante- specimens distributed over a time span) and lopes (Hassanin et al. 2012, Bärmann et al. they are the ones shown in Fig. 1. The tiny Ela- 2013), from among whose early relatives sprang chistoceras khauristanensis has been excluded the Antilopini. The latter contains the Indian because although the originally described mate- blackbuck and its many spiral-horned relatives in rial (Thomas 1977) dating from around 9.0 Ma the Eurasian Late Miocene, as well as the wide- can be accepted as a boselaphine, the conspecifi- spread Gazella and some other genera. A Middle city of some of the rest remains doubtful. Miocene appearance of Gazella seems to be demonstrated in the Siwaliks and east Africa, but it is possible that these supposed early gazelles The commoner Siwaliks bovid could be the ancestors or close relatives of other species genera as well as of later Gazella species. Reduncini evolved from Antilopini, or both The commoner bovids as we find them in the did from undifferentiated early Antilopinae Siwaliks had a long lasting taxonomic stability which would have been little different at that at subfamily/tribal level with occasional altera- stage of their history from primitive Boselaphini. tions of the species occupying what seem to be Today Reduncini are found only in Africa but in ongoing niches (Fig.

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