Peninsular Thailand Research Articles

The nomenclatural status of “Anoplophallus maculatus” Cope, 1895, its consequences on the systematics of Lycodon subcinctus auctorum, and the description of a new species (Squamata: Colubridae)

The Malayan banded wolf snake, Lycodon subcinctus (F. Boie, 1827) has a complicated taxonomic and nomenclatural history. For almost a century, the combination Anoplophallus maculatus Cope, 1895 has been applied to populations of L. subcinctus from southern China, with various authors recognizing the taxon maculatus as a subspecies (i.e., Lycodon subcinctus maculatus) or junior synonym. A recent study that proposed the elevation of Chinese L. subcinctus to species rank (as Lycodon “maculatus”) prompted us to re-investigate several nomenclatural issues relevant to Anoplophallus maculatus that have not been fully addressed in the literature. We show that Anoplophallus maculatus was not described as a new species, and actually refers to Megalops maculatus Hallowell, 1861, a Neotropical snake currently known as Leptodeira maculata (Dipsadinae). As a consequence, populations of L. subcinctus recently recognized as Lycodon “maculatus”, have no valid binomen applied to them. To resolve this issue, we provide a new species name for populations of L. subcinctus from China and include a morphological description based on specimens collected across all of mainland Southeast Asia. The new species, Lycodon neomaculatus sp. nov., occurs well outside of southern China, and inhabits Indochina (Cambodia, Laos, Thailand, Vietnam) and eastern Myanmar. Lycodon neomaculatus sp. nov. is distinguished from both L. sealei and L. subcinctus by subtle differences in adult dorsal color pattern and body scalation. The distributions of L. neomaculatus sp. nov. and L. subcinctus sensu stricto appear to be allopatric, and the Isthmus of Kra region in peninsular Thailand may act as a biogeographic filter separating the two species.

Changes in endangered hornbill populations over space and time and potential ecological impacts in peninsular Thailand

Hornbills are particularly important seed dispersers in tropical Asian forests, but most of the species in the region are declining. In addition, long-term data on the extent of the declines and how forest degradation impacts hornbills remain mostly unquantified. Here, we used multi-covariate distance sampling to estimate the densities of hornbills in 2021–2022 in Hala-Bala Wildlife Sanctuary and Budo Su-Ngai Padi National Park protected areas in southern Thailand. These two sites are particularly useful for comparison due to differences in protection levels, with Bala being relatively less disturbed than Budo Mountain and because Bala was surveyed 20 years prior (2001–2002). Fig tree watches were also conducted in 2021–2022 to assess the potential impact of forest disturbance on hornbill visitation rates. Results indicated significant differences in hornbill densities between the two sites. The mean density of the Rhinoceros (Buceros rhinoceros) and Wreathed Hornbill (Rhyticeros undulatus) was 3.2 and 5.1 times higher in Bala than in Budo, while the mean density of the Great Hornbill (Buceros bicornis) was 2.2 times higher in Budo than in Bala. The density of the Helmeted Hornbill (Rhinoplax vigil) was notably lower than other hornbill species. There were also significant changes over the past 20 years in large hornbill densities, with Great Hornbill and Wreathed Hornbill significantly increasing, while the Helmeted Hornbill declined more than 90 %. Also, the probability of hornbills visiting fruiting Ficus trees was higher in the less-disturbed Bala than the Budo Mountain, making hornbills more reliable visitors in the less-disturbed site. We demonstrate the applicability of the multi-covariate distance sampling approach to estimate densities of rare hornbills, the negative impacts of habitat degradation on hornbills and the ecological role they play as seed dispersers. Additional surveys are needed throughout tropical Asia to establish further sites for long-term monitoring, especially in the Sunda region, where the Helmeted Hornbill is under extreme threat.

Another new species of karst-associated pitviper (Serpentes, Viperidae: Trimeresurus) from the Isthmus of Kra, Peninsular Thailand

We describe a new species of karst-dwelling pitviper from Chumphon Province of Peninsular Thailand, in the Isthmus of Kra, based on morphological and molecular data (2427 bp from cyt b, ND4 and 16S rRNA mitochondrial DNA genes). Morphologically, Trimeresurus kraensis sp. nov. is distinguished from other congeners by the following combination of morphological characters: a dark/bottle-green dorsum with reddish-brown or purple crossbands; pale green venter lacking dark dots; stripes present on the lateral sides of the ventrals; internasals generally in contact; one large supraocular scale on each side of the head; iris pale copper; tail brown with dark purplish-brown crossbars; dorsal scales in 21–21–15 rows; ventral scales 167 in a single male, 169–171 in females; subcaudal scales 62 in a single male, 52–54 in females, all paired. White vertebral spots present in males, located on approximately every two or four dorsal scales; dark brown spots forming discontinuous pattern present on 1–3 lateral dorsal scale rows; males with reddish-brown postocular stripe with jagged edges. The new species differs from the morphologically similar species Trimeresurus venustus s. str. by a notable divergence in cytochrome b mitochondrial DNA gene sequences (p = 5.9%).

Multi-Locus Sequence Analysis Indicates Potential Cryptic Speciation in the Chigger Mite Neoschoengastia gallinarum (Hatori, 1920) Parasitising Birds in Asia.

Neoschoengastia gallinarum is widely distributed in Asia, preferentially parasitising birds, and heavy infestations have clinical impacts on domestic fowl. In common with other trombiculid mites, the genetic diversity and potential variation in host preferences or pathology induced by N. gallinarum are poorly understood. This study aimed to unravel the geographical variation and population structure of N. gallinarum collected from galliform birds in Peninsular Malaysia and Thailand by inference from concatenated mitochondrial-encoded cytochrome c oxidase subunit I (COI), and nuclear-encoded internal transcribed spacer 2 (ITS2) and 18S ribosomal DNA gene sequences, including a comparison with previously published data from southeastern China. Our multi-locus sequence analysis revealed three monophyletic clades comprising (A) specimens from Peninsular Malaysia, (B) the samples from Thailand together with a minority of Chinese sequences, and (C) the majority of sequences from China. Similarly, most species delimitation approaches divided the specimens into three operational taxonomic units. Analysis of molecular variance revealed 96.41% genetic divergence between Malaysian and Thai populations, further supported by the absence of gene flow (Nm = 0.01). In conclusion, despite the two countries sharing a land border, populations of N. gallinarum from Peninsular Malaysia and Thailand appear to be genetically segregated and may represent distinct cryptic species.

The Late Cambrian to Neogene Evolution of the Khanom Core Complex (Peninsular Thailand)

Abstract The Khanom Core Complex in Peninsular Thailand is a part of the crystalline basement of Sundaland and plays a key role in our understanding of the evolution of Thailand and SE Asia. The complex comprises ortho- and paragneisses, schists, meta-volcanics, subordinate calcsilicate rocks, and postkinematic granitoids. New petrochronological data reveal that the sedimentation and metamorphism of the paragneiss precursors (Haad Nai Phlao complex, Khao Yoi paragneisses) occurred in the Late Cambrian at the latest. A syn- to postsedimentary andesitic intrusion/extrusion in the Haad Nai Phlao complex at 495 ± 10 Ma defines a minimum age for the former event(s). In the Early Ordovician (477 ± 7 Ma), the Haad Nai Phlao complex and the Khao Yoi paragneisses were intruded by the Khao Dat Fa granite. During the Indosinian orogenic events, the Laem Thong Yang (211 ± 2 Ma) and Haad Nai Phlao (210 ± 2 Ma) granitoid plutons were intruded. Immediately afterward (ca. 208–205 Ma), the first metamorphic overprinting of the Laem Thong Yang granite and the Haad Nai Phlao complex including the Khao Dat Fa granite occurred. A second metamorphic overprinting of all lithological units and the contemporaneous intrusion of the Khao Pret granite followed in the Late Cretaceous and Early Paleogene (ca. 80–68 Ma). The tectonic formation of the core complex took place in the Eocene (<42 Ma), followed by exhumation and regional cooling below ca. 450°C and the latest cooling to ca. 120°C in the Miocene (ca. 20 Ma). The evolutionary data show that the Khanom Core Complex is part of Sibumasu, and its Late Cretaceous-Neogene cooling pattern and exhumation history can be directly related to the northward drift of India.

From morphology to molecules: A comprehensive study of a novel Derris species (Fabaceae) with a rare flowering habit and reddish leaflet midribs, discovered in Peninsular Thailand.

Derrisrubricosta Boonprajan & Sirich., sp. nov., a new species of the genus Derris Lour. (Fabaceae) was discovered in Peninsular Thailand. The overall morphology demonstrates that the species most resembles D.pubipetala. Nevertheless, the species has several autapomorphies differentiating it from other Derris species, e.g., the presence of reddish midribs of the mature leaflets, sparsely hairy stamen filaments, prominent hairs at the base of the anthers, and presence of glandular trichomes along the leaflet midrib. Additionally, HPLC fingerprints of this species showed a distinction from D.pubipetala by the absence of phytochemical compound peaks after 13 min. Retention Time (RT). Results from molecular phylogenetic analyses also strongly supported the taxonomic status as a new species.

Friesodielsia parvimitra (Annonaceae), a New Species from Peninsular Thailand and a Note on F. argentea.

During botanical expeditions focused on the study of Annonaceae in Thailand, specimens resembling Friesodielsia glauca were collected from the lower part of peninsular Thailand but were believed to differ from that species in vegetative, flower, and fruit characters. A morphological investigation of the new specimens and species complex was conducted. Specimens (including types of F. glauca and similar species collected from Thailand and adjacent regions) were examined in the following herbaria: A, BK, BM, BKF, E, K, KEP, KKU, L, PSU, QBG, SING, and US. As a consequence, the new species Friesodielsia parvimitra, endemic to peninsular Thailand, is described and illustrated. The conservation status of the new species was provisionally assessed as Critically Endangered (CR, B2ab(iii)) following the IUCN's guidelines. In addition, F. argentea, previously regarded F. glauca, is reinstated here as a distinct species based on several morphological differences and is reported as a new record from Thailand. Photographs, line drawings, and a revised key to F. glauca and similar species are presented.

Anthropogenically-induced atmospheric Pb cycle in low-latitude Asia since the Industrial Revolution recorded by high-resolution stalagmites

The vigorous convective circulation in the low-latitude regions plays an important role in the global lead (Pb) cycle in the context of growing atmospheric Pb pollution. However, the brevity of reconstructions of regional Pb pollution limits our understanding of the low-latitude Pb cycle. Here, we presented continuous stalagmite-based Pb records from Klang (KL) cave in the Thai-Malay peninsula, and complementary stalagmite-based Pb records from Xianrenyan (XRY) cave in upwind region to explore the combined effects of atmospheric circulations and anthropogenic Pb emissions on the regional Pb cycle in the low-latitude regions. The analysis suggests that the XRY records reflect regional Pb pollutions in southern China, while the KL records could represent regional Pb recycling in low-latitude Asia, with the Pb pollutants coming from local and upwind territories (e.g., China, India). Moreover, the Pb variations in peninsular Thailand are significantly influenced by the East Asian Winter Monsoon (EAWM) strength with high (low) amount of Pb pollutants from the upwind territories transported to the study area during the strong (weak) EAWM. However, by comparing KL records with XRY records and other existing geological and meteorological records, we found the EAWM-induced Pb variations in the late 20th century were overwhelmed by unprecedented industry-derived Pb emissions from eastern China. Our findings suggest the ever-increasing anthropogenic emission could surpass the atmospheric circulation controls on the regional Pb cycle, offering a new perspective on understanding the relative influence of natural and anthropogenic forcing.

The Pleistocene grassland-dominated mammal fauna from Tham Kra Duk (Nakhon Si Thammarat, Peninsular Thailand)

ABSTRACT Controversy exists as to whether the Pleistocene vegetation in northern Sundaland was dominated by lowland tropical grasslands or rainforests, due to limited palaeoecological evidence recorded from the region. We describe a new Pleistocene large mammal fauna from Tham Kra Duk, a cave in the Tham Phedan mountain, Nakhon Si Thammarat Province in Peninsular Thailand, with emphasis on its palaeoecological and palaeoenvironmental investigations using the stable isotope analysis of mammalian tooth enamel. The fossil site has yielded at least nine mammalian taxa almost comparable to late middle to latest Pleistocene faunas in the mainland, thus suggesting the same biogeographic mammal elements with a range extension south of the Kra Isthmus. The stable isotope results indicate that mixed woodland to grassland ecosystems were dominated by C4 vegetation in the area. This supports the assumption that the expansion of Pleistocene tropical savanna ecosystems might have held the key to facilitating the southward distribution range of grazing mammals such as gaurs and Himalayan gorals into the Thai-Malay Peninsula. The presence of the Tham Kra Duk fauna was probably linked to some major biogeographic events of Pleistocene hominin and mammal migration through the land-bridge peninsula into the islands of Southeast Asia during a period of glaciation.

Trilobites of Thailand's Cambrian–Ordovician Tarutao Group and their geological setting

AbstractTuff‐bearing upper Cambrian to lowermost Ordovician strata on Ko Tarutao island, Satun province, southernmost peninsular Thailand, contain a rich trilobite fauna relevant to global biostratigraphy, peri‐Gondwanan palaeogeography and shifting evolutionary mode. This area of Sibumasu, a lower Palaeozoic marginal Gondwanan terrane, is shown to have been closely associated with Australia, North China (Sino‐Korea) and other continental fragments from the supercontinent's northern equatorial sector, including South China at that time. Shared faunas also suggest a Kazakhstani and Laurentian association. Collections from eight sections yielded 10 newly discovered species and one new genus from ancient shoreface and inner shelf siliciclastic deposits. With the new taxa and revision of taxa known previously, we refine the age of the upper two formations of the Tarutao Group to the middle of Cambrian Stage 10, and lower–middle Tremadocian. Two biozones are erected for Sibumasu: the Eosaukia buravasi Zone, encompassing all Cambrian sections from Ko Tarutao, and the Asaphellus charoenmiti Zone, encompassing the Tremadocian fauna discussed herein. The new genus is Tarutaoia and new species are Tsinania sirindhornae, Pseudokoldinioidia maneekuti, Pagodia? uhleini, Asaphellus charoenmiti, Tarutaoia techawani, Jiia talowaois, Caznaia imsamuti, Anderssonella undulata, Lophosaukia nuchanongi and Corbinia perforata. Other taxa reported for the first time from Tarutao are Mansuyia? sp., Parakoldinioidia callosa Qian, Pseudagnostus sp., Homagnostus sp., Haniwa mucronata Shergold, Haniwa sosanensis? Kobayashi, Lichengia simplex Shergold, Pacootasaukia sp., Wuhuia? sp., Plethopeltella sp., Apatokephalus sp., Akoldinioidia sp. 1 and Koldinioidia sp.

Syn‐ and post‐rift lower crustal flow under the Sunda Shelf, southern Vietnam: A role for climatically modulated erosion

AbstractTectonic subsidence on rifted, passive continental margins are largely controlled by patterns of extension and the nature of strain partitioning in the lithosphere. The Sunda Shelf, adjacent to the SW South China Sea, is characterized by deep basins linked to regional Cenozoic extension associated with propagating seafloor spreading caused by slab pull from the south. Analysis of seismic reflection profiles and drilled sections crossing the Nam Con Son and Cuu Long basins highlight Oligocene extension, with most of the thinning concentrated in the ductile mid‐lower crust. Upper crustal extension was modest and ductile flow is inferred to be directed northwestwards, towards the oceanic crust. Basin inversion occurred in the Mid Miocene, associated with the collision of the Dangerous Grounds Block and Borneo. Subsequent accelerated tectonic subsidence exceeded predictions from uniform extension models assumed to relate to extensional collapse after inversion. We correlate this to a period of faster erosion onshore driven by strong monsoon rains in Indochina and Peninsular Thailand at that time. Erosion of the onshore basement, inducing rock uplift and coupled with loading of the basins offshore, drives ductile mid‐lower crustal flow, likely to the northeast under Indochina, and/or to the west where Plio‐Pleistocene subsidence of the shelf is very slow. Significant sediment delivery from the Mekong River into the Cuu Long Basin began in the Late Miocene and migrated seawards as the basin filled. Mass balancing suggests that the basins of this part of the Sunda Shelf are filled through erosion of bedrock sources around the Gulf of Thailand. There is no need for sediment delivery from a major river draining the Tibetan Plateau to account for the deposited volumes.

A new species of Claderia (Orchidaceae)

A little-studied orchid genus, Claderia Hook.f., has until now contained just one or two species, Claderia viridiflora Hook.f. and its possible synonym, C. papuana Schltr. We describe a new species from Singapore, which differs from these Claderia in having small, cream-yellow flowers that are nodding and presented in a long, unbranched terminal inflorescence, mostly with two flowers open simultaneously. We name the new species Claderia leontocampus Niissalo. Plants of the new species have been collected or recorded in Sumatra, Peninsular Malaysia and possibly Peninsular Thailand. We carried out population genetics analyses to show distinction between the new species and Claderia viridiflora. The two species occur in the same habitat in Singapore. We used phylogenetic analyses to find out the phylogenetic position of Claderia within Orchidaceae; the genus is here considered to belong to subfamily Epidendroideae Kostel., tribe Epidendreae Lindl., subtribe Claderiinae Szlach. We publish the plastome and ITS sequences of Claderia viridiflora. Two names are lectotypified.

Solving the taxonomic identity of Hipposideros cineraceus sensu lato (Chiroptera: Hipposideridae) in the Thai-Malay Peninsula, with the description of a new species.

A new species of small Hipposideros in the bicolor group is described based on specimens from Thailand and Malaysia. It can be distinguished from other small Hipposideros in Southeast Asia by a combination of external, craniodental, and bacular morphology, as well as echolocation call frequency. The new species has a distinct rounded swelling on the internarial septum of the noseleaf, with a forearm length of 35.3-42.6 mm, greatest skull length of 15.94-17.90 mm, and a call frequency of maximum energy of 132.3-144.0 kHz. Although clearly different in morphology, the new species forms a sister clade with H. kunzi and H. bicolor in the phylogenetic trees based on mitochondrial DNA. In addition, this study reports echolocation and genetic data, with a confirmed record of H. einnaythu from Thailand for the first time. The new species most closely resembles H. einnaythu. However, it differs in the details of the noseleaf and craniodental morphology, and it has a genetic distance of 9.6% and 10.4% based on mitochondrial COI and ND2, respectively. It is currently documented from five localities: two in peninsular Thailand, at Hala Forest in Yala Province, and Phru To Daeng Swamp Forest in Narathiwat Province, one from peninsular Malaysia at Krau Wildlife Reserve in Pahang, and another two in Sabah, Malaysian Borneo at Gunung Kinabalu, and near Madai Caves. However, it is likely that many previous records of "H. cineraceus" from Borneo refer to this species. Most records of the species are from lowland evergreen rainforest, though one record from Sabah was at 1800m. The roosting sites for this new species are currently unknown. Future research with a combination of data such as genetics, echolocation and morphology would be necessary to further determine the species geographic distribution in Southeast Asia.

Garcinia exigua (Clusiaceae), a new record for Thailand

Garcinia exigua (Clusiaceae), previously known from Borneo [Malaysia (Sarawak) and Brunei], is reported as a new record from dry evergreen forest on limestone hill in Krabi Province, Peninsular Thailand. A detailed morphological description, illustrations and a distribution map of the species are provided, along with information on distribution, specimens examined, habitat, conservation status, phenology, etymology and vernacular name.

First camera-trap evidence of banded civet Hemigalus derbyanus (Mammalia: Carnivora: Viverridae) in Myanmar

Abstract Banded civet Hemigalus derbyanus is a Near Threatened small carnivore species distributed in Indonesia, Malaysia, Brunei Darussalam, peninsular Thailand, and Myanmar. However, the status of banded civet in Myanmar is uncertain, as it has not been recorded there since 1914. Here, we report the first photographic evidence of banded civet in Htaung Pru Reserved Forest of Tanintharyi Region, which is located in the far northwest from the known historical location in Myanmar, and contributes to our knowledge of the current distribution of banded civet in Southeast Asia. Protection and conservation of lowland rainforest by using community-based conservation approaches is critically important for the persistence of this species in this particular area.

Can electrical wires serve as canopy bridges? A case study of the dusky langur (Trachypithecus obscurus) in Thailand

Abstract In many parts of the world, primates and other arboreal and semi-arboreal species use electrical and telecommunication cables to cross open gaps. However, electrocutions can occur when the cables are uninsulated or damaged. Between 2001 and 2002, during a 12-month behavioural study of two dusky langur groups (Trachypithecus obscurus) at the Royal Thai Air Force Base in Prachuap Khiri Khan Province, peninsular Thailand, we recorded langur use of and mortality on electrical and telecommunications cables on an ad libitum basis. Before insulation of the cables in late 2001, five langurs died by electrocution; post insulation, that number decreased to only one case on March 5, 2002. In 2022, we returned to observe the langur groups and saw them continuing to use the cables for crossing and noted damage to the insulation, indicating the importance of maintenance. Electrical cables can provide canopy connectivity for langurs and prevent dangerous encounters with dogs on the ground, but cables must be insulated and inspected regularly. As additional mitigation measures, we suggest providing alternative substrates for travel such as planting more native trees and providing artificial canopy bridges.

Star anise from a fifteenth century Indonesian shipwreck

AbstractMaritime trade routes in Southeast Asia date to at least the last millennium BC evidenced by excavations of port‐cities, entrepôts and early coastal polities in Peninsular Thailand, the Mekong Delta and Island Southeast Asia. This trade network intensified over the next millennium and by the fifteenth century, the number of trade goods throughout Medieval Southeast Asia was prolific. The bulk of studied material comprises trade ceramics, particularly in archaeological investigations of shipwreck cargoes which provide information on regional trading patterns. Although ceramic assemblages constitute the bulk of shipwreck cargo, other types of material have also been found, including the spice star anise. In this paper, we focus on the organic contents from two jars found in the Bakau shipwreck dating to the early fifteenth century AD. The finds are significant as this spice (star anise, Illicium verum) is being transported together with items of high value for trade.

Taxonomic studies of Araceae in Myanmar V: a new Alocasia species from Myanmar and Thailand

A species new to science, Alocasia epilithica Serebryanyi, K.Z.Hein & Naive discovered in Tanintharyi Region, Myanmar, is herein described and illustrated. This new species was also found to occur in the provinces of Nakhon Si Thammarat and Surat Thani of Peninsular Thailand. Detailed description, color plates, discussion of similar taxa, phenology, distribution map and a preliminary conservation status assessment are provided.

The first wild record of Bulbophyllum lemniscatoides confirms its occurrence in the Philippine archipelago with notes on its habitat and conservation status

Bulbophyllum lemniscatoides Rolfe is a species native to Peninsular Malaysia, Thailand, Laos, Cambodia, Vietnam, Sumatra, Java, and Borneo. It was recently collected in Mt. Timolan Protected Landscape of Zamboanga del Sur, confirming its occurrence in the Philippine archipelago. Here, we provide species descriptions based on our collected material and photographs to aid identification, geographical distribution information, habitat, phenology, and an IUCN conservation assessment.

HULLETTIA King ex Hook. f. (Moraceae), A newly recorded genus to the Flora of Vietnam, with its lectotypification and a revised key to Vietnamese Moraceae

Hullettia King ex Hook. f. (Moraceae) is newly recorded to the flora of Vietnam. A specimen discovered in the lowland secondary evergreen forest of Song Hinh protection forest, Phu Yen province, central Vietnam was identified as Hullettia dumosa King ex Hook. f. It was earlier known from peninsular Myanmar, peninsular Thailand, peninsular Malaysia, Singapore, and Sumatra. Type material of this species is analyzed, and lectotype is designated (Scortechini s.n., K: K000898664). Photographic illustrations of studied specimens are provided. A key to the Vietnamese genera of Moraceae is presented.