Zin-Maung-Maung-Thein,Mandalay University |
Takai M.,Kyoto University |
Uno H.,University of Tokyo |
Wynn J.G.,University of South Florida |
And 7 more authors.
Palaeogeography, Palaeoclimatology, Palaeoecology
The tooth enamel of a mammalian fauna from the uppermost Miocene/lower Pliocene Irrawaddy sediments at Chaingzauk, west-central Myanmar were analyzed using stable carbon and oxygen isotopes. The δ13C values of porcupines, tragulids, rhinocerotids, suids and proboscideans show that these mammals preferentially consumed C3 plants in a wooded environment, whereas the δ13C values of bovids and hippopotamids indicate that they were grassland-adapted grazers to mixed feeders. In contrast to the thorn scrub, grassland and shrubland vegetation of present-day central Myanmar, stable carbon isotope results of the Chaingzauk fauna suggest a presence of wooded environment in the Chaingzauk area at that time. Present-day arid conditions are likely to have been caused by the uplift of the Indo-Burman Ranges due to the Himalayan Orogeny during the late Miocene to Pliocene, resulting in a rainshadow effect in central Myanmar. Furthermore, southward marine regression due to the rapid influx of sediments from the Indo-Burman Ranges, Eastern Himalayan Ranges and Sino-Burman Ranges into the Central Myanmar Basin in the Miocene to Pliocene might have played an important role in the aridification of this region since the lower Pliocene. © 2010 Elsevier B.V. Source
Egi N.,Kyoto University |
Thaung-Htike,Shwebo Degree College |
Zin-Maung-Maung-Thein,Mandalay University |
Maung-Maung,Hinthada University |
And 4 more authors.
Journal of Asian Earth Sciences
A tooth of a mongoose (Mammalia: Carnivora: Herpestidae) was discovered from the Upper Irrawaddy sediments in central Myanmar. The age of the fauna is not older than the mid-Pliocene. It is identified as a right first upper molar of a small species of Urva (formally included in the genus Herpestes) based on its size and shape. The present specimen is the first carnivoran from the Upper Irrawaddy sediments and is the first record of mongooses in the Pliocene and early Pleistocene of Asia. It confirms that mongooses had already dispersed into Southeast Asia by the late Pliocene, being consistent with the previous molecular phylogenetic analyses. The fossil may belong to one of the extant species, but an assignment to a specific species is difficult due to the fragmentary nature of the specimen and the small interspecific differences in dental shape among the Asian mongooses. The size of the tooth suggests that the Irrawaddy specimen is within or close to the clade of Urva auropunctata+. javanica+. edwardsii, and this taxonomic assignment agrees with the geographical distribution. © 2011 Elsevier Ltd. Source
Puechmaille S.J.,University College Dublin |
Puechmaille S.J.,Max Planck Institute for Ornithology (Seewiesen) |
Gouilh M.A.,Mahidol University |
Gouilh M.A.,Institute Pasteur Paris |
And 10 more authors.
The sensory drive theory of speciation predicts that populations of the same species inhabiting different environments can differ in sensory traits, and that this sensory difference can ultimately drive speciation. However, even in the best-known examples of sensory ecology driven speciation, it is uncertain whether the variation in sensory traits is the cause or the consequence of a reduction in levels of gene flow. Here we show strong genetic differentiation, no gene flow and large echolocation differences between the allopatric Myanmar and Thai populations of the world's smallest mammal, Craseonycteris thonglongyai, and suggest that geographic isolation most likely preceded sensory divergence. Within the geographically continuous Thai population, we show that geographic distance has a primary role in limiting gene flow rather than echolocation divergence. In line with sensory-driven speciation models, we suggest that in C. thonglongyai, limited gene flow creates the suitable conditions that favour the evolution of sensory divergence via local adaptation. © 2011 Macmillan Publishers Limited. All rights reserved. Source
Ith S.,Royal University of Phnom Penh |
Soisook P.,Prince of Songkla University |
Bumrungsri S.,Prince of Songkla University |
Kingston T.,Texas Tech University |
And 8 more authors.
Recent field studies have provided new data for a review of the taxonomy, acoustic characters, distribution, and ecology of two often confused rhinolophid species, which have essentially parapatric distributions in continental Southeast Asia. Rhinolophus coelophyllus is widespread ranging from northern Myanmar to northern Malaysia, eastern Thailand and provisionally western Lao PDR. R. shameli is restricted to eastern Thailand, Cambodia, Lao PDR, and central and southern Vietnam. There are well defined differences in skull morphology, size, and echolocation call frequency, which discriminate between the two taxa. © Museum and Institute of Zoology PAS. Source
Licht A.,University of Arizona |
Licht A.,CNRS Institute of Paleoprimatology, Human Paleontoly: Evolution and Paleoenvironments |
Licht A.,French National Center for Scientific Research |
Boura A.,University Pierre and Marie Curie |
And 4 more authors.
Review of Palaeobotany and Palynology
The late middle Eocene Pondaung Formation, Myanmar, has yielded a diversified assemblage of silicified wood including some of the earliest recorded Dipterocarpaceae. However, mid-Palaeogene fossil wood from Asia remains rarely described. We present here three additional species of fossil wood from the upper member of the Pondaung Formation, including a new species of Menispermoxylon (M. mowglii nov. spec.) with successive cambia and included phloem, and two specimens of the fossil genera Glutoxylon (G. burmense Chowdhury) and Heritieroxylon (H. arunachalensis Lakhanpal, Prakash et Awasthi). These three fossil species are related to modern taxa of mangrove and coastal forests in the Bengal Bay and complete the floral assemblage already identified in the Pondaung Formation. The late middle Eocene fossil woods of Myanmar followed a toposequence with mangroves along the seashore, riparian elements similar to those of modern Terai ecosystem in the upper delta plain, and dry dipterocarp forests in the upstream areas of the drainage basin. The latter two assemblages and their association in the landscape are typical of monsoonal areas with significant rainfall and a marked dry season, thus confirming recent studies showing that the Bengal Bay has experienced a significant monsoonal regime as early as 40. Ma ago. The climatic parameters obtained by two quantitative botanical approaches on the Pondaung fossil wood, the coexistence and wood anatomical approaches, suggest similar-to-modern rainfall amount, marked dry season, and warmer annual temperature for the Eocene of Myanmar. They thus support the hypothesis that monsoonal rainfall at that time may have been favored by Eocene greenhouse conditions. However, despite the homogeneity of the Pondaung floral assemblage, several resulting climatic parameters, such as the mean annual temperature (for the coexistence approach) or the mean annual rainfall (for the wood anatomical approach), display large but incomplete uncertainty intervals or unlikely values (for the coexistence and wood anatomical approaches respectively). These limitations can be attributed to the lack of super-warm and super-seasonal stations in their modern databases. It thus indicates that results from both quantitative approaches should be interpreted with caution for palaeo-monsoon reconstruction. © 2015 Elsevier B.V. Source