Systematics of the Neogene Siwalik hipparions (Mammalia, Equidae) based on cranial and dental morphology
- 1 September 1982
- journal article
- research article
- Published by Taylor & Francis in Journal of Vertebrate Paleontology
- Vol. 2 (2), 185-218
- https://doi.org/10.1080/02724634.1982.10011930
Abstract
The systematics of the Neogene Siwalik hipparion horses is based on a review of the classic material from numerous institutions as well as a new biostrati-graphically controlled collection recently made by the Yale–Geological Survey of Pakistan expeditions in the Potwar Plateau region of northern Pakistan. A two-fold taxonomic scheme is presented here. The first, which is based on cranial morphology and associated dentions, indicates that five hipparion species are represented in the Middle Siwalik Group, i.e. Hipparion antelopinum, “Hipparion” feddeni, Cormohipparion theobaldi Cormohipparion cf. nagriensis and “Hipparion” sp. The second scheme, which is based principally on dental measurements, is similar to Hussain's (1971) conclusion that three discrete dental morphologies are represented in the Siwaliks. We prefer to treat these here as Dental Morphs 1,2, and 3 rather than as named species. Characters such as those displayed by dentitions and postcranial remains are here concluded to be less useful in discriminating valid species because of morphological similarities resulting from parallel evolution. However, both cranial morphology and isolated dentitions are biostrati-graphically useful. Most of the Siwalik deposits that yield hipparions are of Turolian and later age; none appear to be Vallesian. As is also seen elsewhere in Holarctica, there is an increase in Siwalik hipparion diversity during the late Miocene and Pliocene. The co-occurence of hipparions and Equus in the Upper Siwaliks elsewhere in the Potwar Plateau is similar to the situation seen in other Old World Pleistocene faunas. In general, Siwalik hipparions are taxonomically derived although there are some phylogenetic similarities to common Turolian species from Europe as well as China.Keywords
This publication has 16 references indexed in Scilit:
- A biostratigraphic zonation of the middle and upper siwaliks of the potwar plateau of Northern PakistanPalaeogeography, Palaeoclimatology, Palaeoecology, 1982
- Magnetic polarity stratigraphy and ages of Siwalik group rocks of the potwar plateau, PakistanPalaeogeography, Palaeoclimatology, Palaeoecology, 1982
- A contribution to the chronology of some Old World miocene faunas based on hipparionine horsesGeobios, 1980
- Revised geomagnetic polarity time scale for the interval 0–5 m.y. B.P.Journal of Geophysical Research, 1979
- Magnetic polarity stratigraphy and vertebrate paleontology of the upper siwalik subgroup of northern PakistanPalaeogeography, Palaeoclimatology, Palaeoecology, 1979
- The magnetic polarity stratigraphy and age of the Siwalik group near Dhok Pathan village, Potwar Plateau, PakistanEarth and Planetary Science Letters, 1978
- Geology and palaeontology of Neogene strata of PakistanNature, 1977
- Magnetic polarity stratigraphy of the Upper Siwalik deposits, Pabbi Hills, PakistanEarth and Planetary Science Letters, 1977
- The late neogene: Biostratigraphy, geochronology and paleoclimatology of the last 15 million years in marine and continental sequencesPalaeogeography, Palaeoclimatology, Palaeoecology, 1974
- A new Siwalik correlationAmerican Journal of Science, 1937