Phytosaur remains (Reptilia,Thecodontia)from the Upper Triassic of North-Eastern Thailand

The recently discovered late Triassic vertebratelocality at Chulabhorn Dam (North-Eastern Thailand) has yielded incomplete remains (jaw fragments and teeth) of phytosaurs, which are apparently indicative of a form related to Belodon and Rutiodon. They can be interpreted as showing that in the late Triassic North-Eastern Thailand was already biogeographically part of Laurasia.     

Cyclotosaurus cf. PosthumusFraas (Capitosauridae,Stereospondyli) from the Huai Hin Lat Formation (Upper Triassic), Northeastern Thailand: With a note on capitosaurid biogeography

Part of a large capitosaurid skull, similar to that of Cyclotosaurus posthumus from the Upper Triassic of Germany, has been discovered in the upper part of the Huai Hin Lat Formation near Chulabhorn (Nam Phrom) Dam. This discovery is consistent with the presumed Norian age of this formation. Although the phylogeny of the Capitosauridae is still unclear, the group of Upper Triassic Cyclotosaurus species to which C. posthumus belongs is monophyletic and seems to be known only from Laurasia or Northwestern Gondwana (Morocco). The occurrence of C. cf. posthumus in Thailand is consistent with the hypothesis previously put forward, that this part of Southeast Asia was bound to Laurasia in Mesozoic times.     

First record of Entelodontidae (Mammalia,Artiodactyla) from the late Eocene of Southeast Asia

We describe two entelodontid upper premolars that were recovered from the late Eocene of the Krabi coal mine in southern Thailand. The size and morphology of the material suggest that it can be referred to Entelodon aff. E. gobiensis, a species known from the late Eocene to the early Oligocene of northern Asia and southern China. The Thai material documents for the first time the southernmost occurrence of entelodontids in Asia during the Paleogene and also suggests that Eocene Southeast Asian mammal localities might potentially yield further entelodontid remains mostly associated with selenodont ungulates.     

The Late Pleistocene Orangutan from Tham Prakai Phet: New discoveries

This paper describes the collection of isolated orangutan fossil teeth identified in the newly excavated material from Tham Prakai Phet, a site located in the Chaiyaphum Province in northeast Thailand. The collection is composed of 18 isolated teeth belonging to Pongo. The morphology of the upper and lower teeth is similar to that of fossil and extant orangutans from mainland Indochina and Indonesia. Only the wrinkles on the occlusal surface are less pronounced and sometimes simpler than extant orangutans. The dimensions of the teeth fall in the range of variation of fossil and extant specimens, but the distribution of the crown areas of the Tham Prakai Phet specimens fall above the mean value observed for extant orangutans. This new collection of continental orangutans confirms the persistence of this taxa in this part of Thailand up to the late Pleistocene, and provides new data useful for understanding the evolution of this hominoid and advance in the reconstitution of the evolutionary lineage of Pongo. The size of the sample from Tham Prakai Phet is not sufficient to determine an accurate taxonomic attribution; pending the increase of the current sample, we attribute the material to Pongo sp. (Pongo aff. weidenreichi).     

Development of 99mTc radiolabeled A85380 derivatives targeting cerebral nicotinic acetylcholine receptor: Novel radiopharmaceutical ligand 99mTc-A-YN-IDA-C4

Nicotinic acetylcholine receptors (nAChRs) are pentameric ligand-gated ion channels that have been implicated in higher brain functions. To elucidate the functional mechanisms underlying nAChRs and contribute significantly to development of drugs targeting neurological and neuropsychiatric diseases, non-invasive nuclear medical imaging can be used for evaluation. In addition, technetium-99m (^99mTc) is a versatile radionuclide used clinically as a tracer in single-photon emission computed tomography. Because A85380 is known as a potent α4β2-nAChR agonist, we prepared A85380 derivatives labeled with ^99mTc using a bifunctional chelate system. A computational scientific approach was used to design the probe efficiently. We used non-radioactive rhenium (Re) for a ^99mTc analog and found that one of the derivatives, Re-A-YN-IDA-C4, exhibited high binding affinity at α4β2-nAChR in both the docking simulation (?19.3 kcal/mol) and binding assay (Ki = 0.4 ± 0.04 nM). Further, ^99mTc-A-YN-IDA-C4 was synthesized using microwaves, and its properties were examined. Consequently, we found that ^99mTc-A-YN-IDA-C4, with a structure optimized by using computational chemistry techniques, maintained affinity and selectivity for nAChR in vitro and possessed efficient characteristics as a nuclear medicine molecular imaging probe, demonstrated usefulness of computational scientific approach for molecular improvement strategy.     

Microrestes de Vertébrés du Siluro-Dévonien d'Algérie,de Turquie et de Thaïlande

Acanthodian («Shark-like spiny fishes) scaleshave been collected in three Uppermost Silurian-Lowermost Devonian localities from Algeria, southeastern Turkey and Thailand, in association with agnathan remains (heterostracans in Algeria, thelodonts in Thailand). These vertebrate microremains are the oldest ones for those three countries. They were associated with marine invertebrate faunas and are supposed to have lived in littoral environments. Their world-wide biogeographical distribution by the Silurian-Devonian boundary leads to analyse the palaeogeographical relations of north-Atlantis and Siberia on one hand, with southern Europe, southeastern Asia and Gondwanaland on the other hand.     

Wing geometry of Phlebotomus stantoni and Sergentomyia hodgsoni from different geographical locations in Thailand

Geographic populations of the two main sandflies genera present in Thailand were studied for species and population identification. Size and shape of Phlebotomus stantoni and Sergentomyia hodgsoni from different island and mainland locations were examined by landmark-based geometric morphometrics. Intraspecific and interspecific wing comparison was carried out based on 12 anatomical landmarks. The wing centroid size of P. stantoni was generally larger than that of S. hodgsoni. Within both species, wings from the continent were significantly larger than those from island populations. Size variation could be significant between geographic locations, but could also overlap between genera. The wing venation geometry showed non-overlapping differences between two species. The within-species variation of geometric shape between different geographical locations was highly significant, but it could not interfere with the interspecies difference. The lack of species overlapping in shape, and the high discrimination between geographic populations, make geometric shape a promising character for future taxonomic and epidemiological studies.     

Geological significance of the discovery of Middle Triassic (Ladinian) radiolarians from the Hong Hoi Formation of the Lampang Group,Sukhothai Zone,northern Thailand

This paper presents a newly found fauna of Ladinian (Middle Triassic) radiolarians from the Hong Hoi Formation of the Lampang Group, Sukhothai Zone, northern Thailand. The Ladinian age determined by the radiolarian fauna concords with the age previously determined by mollusks. The study section consists of intercalated sandstone and shale in the lower part and a thick conglomerate in the upper part. The radiolarian-bearing siliceous beds are intercalated within the lower unit. The lithic sandstone of the lower unit consists mainly of volcanic rock fragments, quartz, and feldspar, whereas the thickly bedded conglomerate of the upper unit is characterized by abundant gravel-sized clasts of volcanic rock and limestone. These lithic features of the study section suggest that during deposition the Hong Hoi Formation was located near a supply of volcanic materials. A forearc basin close to the Sukhothai Arc would be the most suitable environment for the deposition. The Ladinian age determined by the radiolarian fauna supports the occurrence of intensive volcanic activity within the Sukhothai Arc during the Middle Triassic.     

Freshwater crocodile,Crocodylus siamensis Schneider, 1801, from the Middle Pleistocene deposits in Chaloem Phrakiat District,Nakhon Ratchasima,Thailand

Two crocodilian anterior cranium parts from Takut Khon Village sand pit, Chaloem Phrakiat District, Nakhon Ratchasima Province, are presently described. Their morphology indicates that the specimens belong to a single species based on the presence of several similar characters such as a hole for the reception of the first dentary tooth at the anterior edge of the premaxillary bone; anterior tip of nasal elongate and projecting into the posterior margin of the external nares; wavy suture line between the posterior part of the nasal with the anterior margin of prefrontal and frontal processes. The cranium morphology is extremely close to Crocodylus siamensis Schneider, 1801 (Siamese crocodile) and conforming the existence of C. siamensis from the Middle Pleistocene in Thailand.     

Dinosaur footprints from the Sao Khua Formation (Early Cretaceous) of Phu Kao National Park,Northeast Thailand

The first documented dinosaur footprints from Southeast Asia were theropod footprints found in Thailand at Phu Luang Wildlife Sanctuary. Since then, Mesozoic vertebrate footprints have been discovered in twelve different localities in Thailand. In 2000, dinosaur footprints were found in Phu Kao National Park in Northeastern Thailand, however, they have never been studied in detail. The following study presents the first map, the complete measurements, the geology, and stratigraphy of the site and surrounding area. The study discusses the nature of the trackmaker and the digitigrade character of the footprints. This discovery represents the first documented occurrence of dinosaur footprints inside the Early Cretaceous Sao Khua Formation from Thailand.