Acta Palaeontologica Polonica

New early Eocene tapiromorph perissodactyls from the Ghazij Formation of Pakistan, with implications for mammalian biochronology in Asia

Pieter Missiaen and Philip D. Gingerich

Acta Palaeontologica Polonica 57 (1), 2012: 21-34 doi: http://dx.doi.org/10.4202/app.2010.0093

Early Eocene mammals from Indo−Pakistan have only recently come under study. Here we describe the first tapiromorph perissodactyls from the subcontinent. Gandheralophus minor gen. et sp. nov. and G. robustus sp. nov. are two species of Isectolophidae differing in size and in reduction of the anterior dentition. Gandheralophus is probably derived from a primitive isectolophid such as Orientolophus hengdongensis from the earliest Eocene of China, and may be part of a South Asian lineage that also contains Karagalax from the middle Eocene of Pakistan. Two specimens are referred to a new, unnamed species of Lophialetidae. Finally, a highly diagnostic M3 and a molar fragment are described as the new eomoropid chalicothere Litolophus ghazijensis sp. nov. The perissodactyls described here, in contrast to most other mammalian groups published from the early Eocene of Indo−Pakistan, are most closely related to forms known from East and Central Asia, where Eocene tapiromorphs are diverse and biochronologically important. Our results therefore allow the first biochronological correlation between early Eocene mammal faunas in Indo−Pakistan and the rest of Asia. We suggest that the upper Ghazij Formation of Pakistan is best correlated with the middle or late part of the Bumbanian Asian Land Mammal Age, while the Kuldana and Subathu Formations of Pakistan and India are best correlated with the Arshantan Asian Land Mammal Age.

Key words: Perissodactyla, Isectolophidae, Lophialetidae, Eomoropidae, biochronology, early Eocene, Ghazij Formation, Pakistan.

Pieter Missiaen [pieter.missiaen@ugent.be], Royal Belgian Institute of Natural Sciences (RBINS), Department of Paleontology, rue Vautier 29, B-1000 Brussels, Belgium; Ghent University, Research Unit Palaeontology, Krijgslaan 281-S8, B-9000 Ghent, Belgium; and University of Michigan, Museum of Paleontology, Geddes Road 1109, Ann Arbor 48109-1079 USA; Philip D. Gingerich [gingeric@umich.edu], University of Michigan, Museum of Paleontology, Geddes Road 1109, Ann Arbor 48109-1079 USA.


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