title: First discovery of colobine fossils from the Late Miocene/Early Pliocene in central Myanmar.
abstract: Here we report two kinds of colobine fossils discovered from the latest Miocene/Early Pliocene Irrawaddy sediments of the Chaingzauk area, central Myanmar. A left mandibular corpus fragment preserving M1-3 is named as a new genus and species, Myanmarcolobus yawensis. Isolated upper (M(1)?) and lower (M2) molars are tentatively identified as Colobinae gen. et sp. indet. Although both forms are medium-sized colobines, they are quite different from each other in M2 morphology. The isolated teeth of the latter show typical colobine-type features, so it is difficult to identify their taxonomic position, whereas lower molars of Myanmarcolobus have unique features, such as a trapezoid-shaped long median lingual notch, a deeply concave median buccal cleft, a strongly developed mesiobuccal notch, and rather obliquely running transverse lophids. Compared with fossil and living Eurasian colobine genera, Myanmarcolobus is most similar in lower molar morphology to the Pliocene Dolichopithecus of Europe rather than to any Asian forms. In Dolichopithecus, however, the tooth size is much larger and the median lingual notch is mesiodistally much shorter than that of Myanmarcolobus. The discovery of Myanmarcolobus in central Myanmar is the oldest fossil record in Southeast Asia not only of colobine but also of cercopithecid monkeys and raises many questions regarding the evolutionary history of Asian colobine monkeys.
authors.affiliation: Primate Research Institute, Kyoto University, Inuyama, Aichi 484-8506, Japan. Electronic address: takai.masanaru.2s@kyoto-u.ac.jp.
authors.forename: Masanaru
authors.initials: M
authors.lastname: Takai
authors.affiliation: Shwebo University, Shwebo, Myanmar.
authors.lastname: Thaung-Htike
authors.affiliation: Mandalay University, Mandalay, Myanmar.
authors.lastname: Zin-Maung-Maung-Thein
authors.affiliation: Defence Service Academy, Pyin Oo Lwin, Myanmar.
authors.forename: Aung Naing
authors.initials: AN
authors.lastname: Soe
authors.affiliation: Magway University, Magway, Myanmar.
authors.forename: Maung
authors.initials: M
authors.lastname: Maung
authors.affiliation: Hayashibara Museum of Natural Sciences, Setouchi 701-4212, Japan.
authors.forename: Takehisa
authors.initials: T
authors.lastname: Tsubamoto
authors.affiliation: Primate Research Institute, Kyoto University, Inuyama, Aichi 484-8506, Japan.
authors.forename: Naoko
authors.initials: N
authors.lastname: Egi
authors.affiliation: Primate Research Institute, Kyoto University, Inuyama, Aichi 484-8506, Japan.
authors.forename: Takeshi D
authors.initials: TD
authors.lastname: Nishimura
authors.affiliation: Primate Research Institute, Kyoto University, Inuyama, Aichi 484-8506, Japan.
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Nishioka
mesh_terms: D000818:Animals; D005075:Biological Evolution; D016673:Colobinae / Q000033:anatomy & histology* / Q000145:classification*; D005580:Fossils / Q000033:anatomy & histology*; D008334:Mandible / Q000033:anatomy & histology; D008437:Maxilla / Q000033:anatomy & histology; D008963:Molar / Q000033:anatomy & histology; D002052:Myanmar
keywords: Cercopithecidae; Colobinae; Irrawaddy sediments; Late Neogene; Myanmarcolobus; Southeast Asia