Hominoid fossils discovered from Chiang Muan, northern Thailand: The first step towards understanding hominoid evolution in Neogene Southeast Asia

Abstract

The Thai-Japanese Paleontological Expedition Team (TJPET) has been conducting paleontological and geological fieldwork in Thailand for a number of years. In January 2000, an upper molar (CMu6-1'00) of a large-bodied Miocene hominoid was found by TJPET in a lignite mine in the Chiang Muan basin, northern Thailand. It was the first record of a Miocene hominoid from a Southeast Asian country. Two years later, TJPET found a second hominoid specimen (CMu15-5'01) in the same lignite mine. The second specimen was collected from the Upper Lignite Member, while the first one had come from the Lower Lignite Member. The age of Chiang Muan is estimated to be at around the boundary of the Middle/Late Miocene (ca. 10-12 Ma) based on mammalian fauna and paleomagnetic study. There may be several hundred thousand years temporal difference between the Upper and Lower Lignite Members. Chaimanee et al. (2003) reported more hominoid specimens from the same site, and created a new species, cf. Lufengpithecus chiangmuanensis. The taxonomic status of the Chiang Muan hominoids, however, is still a matter of debate. Nevertheless, the discovery of Miocene hominoids from Chiang Muan has revealed the potential of Thailand for understanding hominoid evolution in Southeast Asia. © 2004 The Anthropological Society of Nippon.