Peninsular Thailand (peninsular + thailand)

Distribution by Scientific Domains


Selected Abstracts


EARLY ORDOVICIAN CONODONTS FROM TARUTAO ISLAND, SOUTHERN PENINSULAR THAILAND

PALAEONTOLOGY, Issue 6 2008
SACHIKO AGEMATSU
Abstract:, Early Ordovician conodont faunas of the Thung Song Formation on Tarutao Island, southern peninsular Thailand, consist of 14 known species belonging to 17 genera, and eight undescribed species. Utahconus tarutaoensis and Filodontus tenuis are new species. Three conodont zones: the Rossodus manitouensis Zone, the Utahconus tarutaoensis Zone and the Filodontus tenuis Zone, in ascending order, are defined in the study sections. These are coeval with the interval from the Rossodus manitouensis Zone to the Acodus deltatus - Oneotodus costatus Zone of the standard zonation in the North American Midcontinent. Based on the conodonts studied here and fossils previously reported from Tarutao Island, the Thung Song Formation is early Tremadocian to middle Arenig (Ibexian) in age. This formation is lithostratigraphically subdivided into the S1 to S5 members, and our study sections consist of the S1 to S3 members. These strata accumulated on a shelf in the Early Ordovician. The depositional environments of the limestones making up the S1 and S3 members were in deeper-shelf conditions. Limestone and shale of the S2 member formed in a shallow-water, high-energy environment. [source]


New strepsirrhine primate from the late Eocene of Peninsular Thailand (Krabi Basin)

AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 4 2006
Laurent Marivaux
Abstract In this paper, we describe the newly discovered lower jaw of a primate from the late Eocene Krabi coal mine (Bang Mark pit) of Peninsular Thailand. We performed microtomographic examinations at the European Synchrotron Radiation Facility (ESRF, Grenoble, France) to analyze different morphological aspects of the jaw and teeth. Although partially preserved, this fossil mandible reveals a set of distinctive dental traits (e.g., double-rooted P2 and molarized P4) that allow us to describe a new stepsirrhine adapiform: Muangthanhinius siami, new genus and species. This taxon is somewhat atypical among Paleogene adapiforms, and more specialized than the sivaladapid adapiforms (hoanghoniines) that existed in Asia in the same epoch. In fact, Muangthanhinius shows a degree of dental specialization approximating that of some modern strepsirrhine lemuriforms, although it lacks the highly specialized anterior dentition characterizing this living primate group (canine + incisors forming a very procumbent toothcomb). In contrast, Muangthanhinius exhibits a large canine deeply anchored within the dentary that probably protruded high above the toothrow. Finally, despite the development of a molarized P4 as in Miocene sivaladapid sivaladapines, Muangthanhinius differs in molar morphology from this group, and the position of this new taxon within the Adapiformes remains indeterminate. Clarification of its phylogenetic position will require more morphological evidence than is currently available. Am J Phys Anthropol, 2006. © 2006 Wiley-Liss, Inc. [source]


Complex population history of two Anopheles dirus mosquito species in Southeast Asia suggests the influence of Pleistocene climate change rather than human-mediated effects

JOURNAL OF EVOLUTIONARY BIOLOGY, Issue 6 2008
S. M. O'LOUGHLIN
Abstract Anopheles dirus and Anopheles baimaii are closely related species which feed on primates, particularly humans, and transmit malaria in the tropical forests of mainland Southeast Asia. Here, we report an in-depth phylogeographic picture based on 269 individuals from 21 populations from mainland Southeast Asia. Analysis of 1537 bp of mtDNA sequence revealed that the population history of A. baimaii is far more complex than previously thought. An old expansion (pre-300 kyr BP) was inferred in northern India/Bangladesh with a wave of south-eastwards expansion arriving at the Thai border (ca 135,173 kyr BP) followed by leptokurtic dispersal very recently (ca 16 kyr BP) into peninsular Thailand. The long and complex population history of these anthropophilic species suggests their expansions are not in response to the relatively recent (ca 40 kyr BP) human expansions in mainland Southeast Asia but, rather, fit well with our understanding of Pleistocene climatic change there. [source]


EARLY ORDOVICIAN CONODONTS FROM TARUTAO ISLAND, SOUTHERN PENINSULAR THAILAND

PALAEONTOLOGY, Issue 6 2008
SACHIKO AGEMATSU
Abstract:, Early Ordovician conodont faunas of the Thung Song Formation on Tarutao Island, southern peninsular Thailand, consist of 14 known species belonging to 17 genera, and eight undescribed species. Utahconus tarutaoensis and Filodontus tenuis are new species. Three conodont zones: the Rossodus manitouensis Zone, the Utahconus tarutaoensis Zone and the Filodontus tenuis Zone, in ascending order, are defined in the study sections. These are coeval with the interval from the Rossodus manitouensis Zone to the Acodus deltatus - Oneotodus costatus Zone of the standard zonation in the North American Midcontinent. Based on the conodonts studied here and fossils previously reported from Tarutao Island, the Thung Song Formation is early Tremadocian to middle Arenig (Ibexian) in age. This formation is lithostratigraphically subdivided into the S1 to S5 members, and our study sections consist of the S1 to S3 members. These strata accumulated on a shelf in the Early Ordovician. The depositional environments of the limestones making up the S1 and S3 members were in deeper-shelf conditions. Limestone and shale of the S2 member formed in a shallow-water, high-energy environment. [source]