Mainland Southeast Asia Research Articles

An integrative approach to a revision of the freshwater mussel genus Songkhlanaia (Bivalvia, Unionidae), with the description of a new species

Mainland Southeast Asia, also known as Indochina, is recognized as a global biodiversity hotspot for freshwater mussels, hosting a significant number of species and exhibiting high levels of endemism. Recently, the monotypic genus Songkhlanaia was described from the Songkhla Lake Basin in southern Thailand. In this study, two additional lineages are revealed, S. moreleticomb. nov. and S. songkhramensissp. nov., from the Mekong Basin through an integrative taxonomic approach combining morphological characters and molecular phylogenetic analyses. The multi-locus phylogenetic inference supported the monophyly of the genus and further elucidated the sister relationship between S. moreleti and the new species, and with S. tamodienica positioned as a basal lineage. Pairwise uncorrected COI p-distances among these three species also supported the species validity and ranged from 4.2% to 8.24%. Notably, S. songkhramensissp. nov. and S. moreleti exhibit similarities in shell morphology; however, the new species can be differentiated by more robust pseudocardinal teeth. Both species are distinguishable from S. tamodienica by their approximately twice larger size, more inflated shells, and more prominent, roughened, irregular growth lines on the shell surface. Furthermore, based on the current data, these three species are recognized as endemic and are restricted to disjunct biogeographic areas in Indochina: S. tamodienica in the Songkhla Lake Basin in southern Thailand, S. moreleti in the Tonle Sap and Lower Mekong basins, and S. songkhramensissp. nov. in the Songkhram Basin and its nearby tributaries of the Middle Mekong Basin.

A new section in Asian Thismia (Thismiaceae), T. sect. Mirabiles, and its checklist

The paper continues a series of contributions aimed to develop a phylogenetically sound sectional subdivision of the mycoheterotrophic genus Thismia. Here, a formal taxonomic status is provided for a remarkable monophyletic Asian group of species that is also well-defined morphologically within the genus. It is demonstrated that no supraspecific taxon name of any rank is available for this group. Hence, a new section, Thismia sect. Mirabiles, is established. Inconsistencies are highlighted in the earlier treatments where the species placed here in Thismia sect. Mirabiles were assigned to Thismia sect. Sarcosiphon. Indeed, in all such treatments, either the taxon monophyly or the nomenclatural applicability of the latter sectional name is violated. A checklist of the newly described section is provided along with an identification key to its species. The section is currently known to comprise eight species mainly distributed in mainland Southeast Asia and including a species endemic to the Andaman and Nicobar Islands.

Spatio-temporal analysis of formaldehyde and its association with atmospheric and environmental variables over the Southeast Asian region using satellite data.

This study investigates the spatio-temporal distribution of formaldehyde (HCHO) over the mainland Southeast Asian region (including Northeast India) from 2019 to 2022 using TROPOMI satellite data. HCHO is a key atmospheric trace gas which is influenced by both natural processes and anthropogenic activities. We analyze HCHO levels in relation to atmospheric species including carbon monoxide (CO), nitrogen dioxide (NO2), and environmental factors such as land surface temperature (LST), precipitation (PPT), fire radiative power (FRP), and enhanced vegetation index (EVI). Peak levels of HCHO are particularly observed in March and April, which coincide with the dry and warm seasons and reflect seasonal variability arising from both fluctuating emission sources and regional climate patterns. Correlation analyses reveal significant associations between HCHO and CO (r = 0.727), followed by HCHO and NO2 (r = 0.577) and HCHO and LST (r = 0.539). Conversely, a negative correlation with PPT (r = - 0.233) is observed as HCHO decreases with increased precipitation due to washout. The negative correlation with EVI (r = - 0.319) is unexpected since biogenic emissions are significant contributors to HCHO. This outcome likely results from the confounding effect of precipitation. A robust multiple regression model incorporating these variables is developed which is able to explain 61.8% of the variance in HCHO. It enhances predictive capabilities facilitating the estimation of HCHO distribution and supporting air quality management efforts in the region. This research contributes to understanding the complex interactions of HCHO with atmospheric chemistry and climate variability in Southeast Asia. Insights gained from this study are crucial for informing environmental policies aimed at reducing air pollution and protecting public health in rapidly developing regions.

Government and farmer responses to the fall armyworm outbreak in mainland Southeast Asia

IntroductionNative to the Americas and highly polyphagous, the fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) has garnered attention for causing significant damage, primarily to maize.MethodsThis study synthesizes FAW emergence, government responses, and farmer reactions in mainland Southeast Asia (MSEA), and assesses the feasibility of government-recommended measures in terms of efficacy and cost-efficiency.ResultsFrom late 2018 to the rainy season of 2019, FAW infestations extensively emerged in MSEA maize fields. MSEA governments promptly issued strategies and guidelines through plant protection divisions/departments, which involved international organizations, foreign governments, and private web portals. Alongside the foliar application of emamectin benzoate (EMB), which is the most frequently mentioned method, MSEA governments advocated for integrated pest management (IPM)-oriented approaches. These include application methods of chemical insecticides, use of host plant resistance, biological control, cultural and interference methods, and local measures aimed at reducing chemical usage. Despite comprehensive recommendations, maize farmers primarily rely on EMB foliar treatment for FAW control.DiscussionWe highlight the need for further research and dissemination regarding the widely accepted foliar application of chemical insecticides, specifically in relation to human safety, improvements in application technology, and clear guidelines for large-scale outbreaks. On the other hand, the concentrative foliar application of chemical insecticides raises concerns about resistance evolution. Alternatives to foliar treatment with chemical insecticides, mainly EMB, such as seed treatment with diamides and neonicotinoids, genetically modified maize seeds approved only in Vietnam, and biological control, have demonstrated efficacy. Seed treatment provides cost and labor benefits for early-stage FAW infestation prevention. Validation of natural enemy rearing costs may prove advantageous as preliminary estimates suggest they could be relatively low. Not all strategies recommended by the government or widely discussed are necessarily relevant at farm-level. This study provides the following suggestions for the proposal of more acceptable strategies. 1) Studying the actual responses of governments and farmers with special emphasis on cost efficiency; 2) Making alternatives to EMB foliar application more cost-effective inclusive of the cost of labor; and finally, 3) Verifying the effectiveness of the alternative techniques.

The Chee Kung Tong: a voluntary sworn brotherhood across the Cantonese world

ABSTRACT This article examines the development of the Cantonese sworn brotherhood, the Chee Kung Tong, in global perspective. By examining the broad thematic similarities between the chapters that developed around the world, this article argues that the Chee Kung Tong adapted the sworn brotherhood, an associational form long used in mainland China and Southeast Asia, into a flexible organization able to meet the needs of mobile and vulnerable Cantonese migrants. At the same time, it used the circulation of rituals, goods, and people, to unite scattered migrants into the same fictive family.

Reconstructing the population history of theNicobarese.

The Nicobarese are the major tribal groups in the Nicobar district, situated south of the Andaman group of Islands. Linguistic phylogeny suggests that the linguistic ancestors of the Nicobarese settled the Nicobar archipelago in the early Holocene. So far, genetic research on them is low-resolution and restricted to the haploid DNA markers. Therefore, in the present analysis, we have used the high-resolution biparental (1554 published and 5 newly genotyped Nicobarese individuals) and uniparental genetic markers and looked at the genetic association of Nicobarese with the South and Southeast Asian populations. We report a common ancestral component shared among the Austroasiatic of South and Southeast Asia. Our analyses have suggested that the Nicobarese peoples retain this ancestral Austroasiatic predominant component in their genomes in the highest proportion. On the Southeast Asian mainland, the Htin Mal, who speak an Austroasiatic language of the Khmuic branch, represent a population that has preserved their ethnic distinctness from other groups over time and consequently shown the highest drift with the Nicobarese. The analysis based on haplotypes indicated a significant level of genomic segment sharing across linguistic groups, indicating an ancient broader distribution of Austroasiatic populations in Southeast Asia. Based on the temporal analyses of haploid DNA, it is suggested that the forebears of the Nicobarese people may have arrived on the Nicobar Islands in the last 5000 YBP. Therefore, among the modern populations, the Nicobarese peoples and the Htin Mal language community represent good genetic proxies for ancient Austroasiatics.

A Study of Communities of Practice in Craft Production from Log Coffin Culture Archaeological Sites in Highland Pang Mapha, Northwestern Thailand

Abstract In the late prehistoric and early historic periods (2,120–1,250 B.P.) in highland Pang Mapha, northwestern Thailand, the Log Coffin Culture represented a unique mortuary practice characterized by specific cemetery locations and coffin stylistic variations within a localized region of mainland Southeast Asia. Highland peoples practiced these mortuary patterns for an extended period, indicating that specialized cultural practices were passed between successive generations. This article examines the communities of practice of coffin production to understand how this knowledge transmission occurred over roughly 1,000 years. We conducted a quantitative analysis of 202 coffin heads from four river drainages. Similarities of coffin head proportion and carving techniques suggest that highland peoples shared techniques among craft communities in sub-regional watersheds, including the Lang, Mae Lana and Khong rivers, for generations. The difference in head proportion and surface treatment also suggests that producers conceivably adopted some aspects of traditional techniques and developed individual styles.

Regionally extensive ejecta layer of the Australasian tektite strewn field: the MIS 20/19 large meteorite impact in mainland South-East Asia

Aspects of the Quaternary sedimentary geology of South-East Asia have proven problematic in terms of interpretation as to the origins and relationships of the surface sediment layers. The MIS 20 large meteorite impact (c., 788 to 785 ka) occurred within mainland South-East Asia, evident from the well-researched ‘Australasian Tektite Strewn Field’ which extends over at least one tenth of the surface of the Earth. Key questions include: 1) whether the sedimentary impact signature is preserved in the Quaternary sediment cover of the region and 2) whether stratigraphic indicators and dating methods can discriminate meteorite impact-related associations of sedimentary strata, despite subsequent reworking and diagenesis. The importance of the questions raised relate to the search for the impact site, which has not been located conclusively. Moreover, the sedimentary signatures of meteorite impacts are not well known and the descriptions in this study should aid the recognition of impact signatures elsewhere in the world. An hypothesis was developed: Surface Quaternary sediments across a wide area of mainland South-East Asia represent the effects of a regionally significant meteorite impact. Over one hundred sedimentary sections were logged across five countries in mainland South-East Asia. Methods used, defining the stratigraphy and sedimentology, include computed tomography and X-ray scanning, geochemistry, magnetic susceptibility, and environmental luminescence as well as conventional grain size analyses. Luminescence analyses were applied to samples from key strata to provide age constraints and indications of reworking through dose distributional analysis of quartz fractions. The results of the investigation explain the nature of the stratigraphy and relate it specifically to the meteorite impact. In this manner, the strata and sedimentary signatures of the ejecta from a large cosmic impact are defined across a broad region, rather than being described at singular and isolated sections. The novelty is the spatial scale of the investigation which nevertheless remains detailed. A summary model of impact stratigraphy is presented that applies to the regional ejecta blanket covering at least 300,000 km2. Tektites were co-deposited with the ejecta and not introduced by surface processes reworking the deposits. Similar models may be applicable outside of mainland South-East Asia, wherever other large impacts are suspected to have occurred.

Review of the Slender Geckos (Squamata: Gekkonidae: Hemiphyllodactylus) of the Cardamom Mountains of southwestern Cambodia, with descriptions of two new species and one country record.

The gekkonid lizard genus Hemiphyllodactylus contains small, secretive species that are often overlooked in their habitats. Recent molecular and morphological analyses have resulted in the descriptions of numerous new species of Hemiphyllodactylus in mainland Southeast Asia and southern China, many of which were historically hidden within the geographically widespread taxon H. yunnanensis (Boulenger, 1903). Little is known on species diversity and distributions of Hemiphyllodactylus in Cambodia, and all previous reports from the country have been limited to provisional identifications owing to collections containing only a single female or juvenile specimen. We report on new collections of Hemiphyllodactylus specimens from opposite ends of the Cardamom Mountain range in southwestern Cambodia. Morphological and molecular data support the hypothesis that these collections contain three distinct species, two of which are described as new species and one of which is assigned to the geographically widespread H. typus Bleeker, 1860 as a new country record for Cambodia. Hemiphyllodactylus bokor sp. nov. from Preah Monivong Bokor National Park in Kampot Province and Hemiphyllodactylus samkos sp. nov. from Phnom Samkos Wildlife Sanctuary in Pursat Province are related to species from adjacent areas in southern Vietnam, southern Laos, and southeastern Thailand, as well as a clade from India, but are readily differentiated in mitochondrial DNA and in having unique combinations of mensural and meristic morphological characters. Additional species diversity of Hemiphyllodactylus likely exists in Cambodia.

The Family Bithyniidae Gray, 1857 (Gastropoda: Truncatelloidea) in Peninsular Malaysia and Singapore

Freshwater snails of the family Bithyniidae on mainland Southeast Asia are important intermediate hosts of zoonotic parasites. However, bithyniids in the southern tip of the mainland, in Peninsular Malaysia and Singapore, have remained largely overlooked. We review records of the bithyniids from this target region based on literature and museum material to verify species identities, statuses and distribution. Species identification was conducted mainly using shell characters and supplemented by analyses of the COI gene. We recorded four species—Digoniostoma siamensis siamensis, Gabbia minuta, Gabbia cf. stenothyroides, Wattebledia baschi. In Malaysia, G. minuta and W. baschi are only known from their type localities. Digoniostoma siamensis siamensis occurs in Peninsular Malaysia and was introduced to Singapore in recent decades. Gabbia cf. stenothyroides has also been introduced to Singapore. Molecular analyses indicated that D. siamensis siamensis shares the same clade with mainland Southeast Asian Bithynia spp., Gabbia cf. stenothyroides is sister to a bithyniid from Sulawesi, while Bithynia and Gabbia were recovered as non-monophyletic groups. Our study clarifies the presence of two introduced bithyniids in Singapore, reveals the lack of knowledge on native (including endemic) Malaysian species, and further emphasises the need for a revision of all bithyniids.

Effect of Biomass Burnings on Population Exposure and Health Impact at the End of 2019 Dry Season in Southeast Asia

At the end of the dry season, from early March to early April each year, extensive agricultural biomass waste burnings occur throughout insular mainland Southeast Asia. During this biomass-burning period, smoke aerosols blanketed the whole region and were transported and dispersed by predominant westerly and southwesterly winds to southern China, Taiwan, and as far southern Japan and the Philippines. The extensive and intense burnings coincided with some wildfires in the forests due to high temperatures, making the region one of the global hot spots of biomass fires. In this study, we focus on the effect of pollutants emitted from biomass burnings in March 2019 at the height of the burning period on the exposed population and their health impact. The Weather Research Forecast-Chemistry (WRF-Chem) model was used to predict the PM2.5 concentration over the simulating domain, and health impacts were then assessed on the exposed population in the four countries of Southeast Asia, namely Thailand, Laos, Cambodia, and Vietnam. Using the health impact based on log-linear concentration-response function and Integrated Exposure Response (IER), the results show that at the peak period of the burnings from 13 to 20 March 2019, Thailand experienced the highest impact, with an estimated 2170 premature deaths. Laos, Vietnam, and Cambodia followed, with estimated mortalities of 277, 565, and 315 deaths, respectively. However, when considering the impact per head of population, Laos exhibited the highest impact, followed by Thailand, Cambodia, and Vietnam. The results highlight the significant health impact of agricultural waste burnings in Southeast Asia at the end of the dry season. Hence, policymakers should take these into account to design measures to reduce the negative impact of widespread burnings on the exposed population in the region.

From past to future: digital methods towards artefact analysis

Abstract Over the past two decades, Digital Humanities has transformed the landscape of humanities and social sciences, enabling advanced computational analysis and interpretation of extensive datasets. Notably, recent initiatives in Southeast Asia, particularly in Singapore, focus on categorizing and archiving historical data such as artwork, literature and, most notably archaeological artefacts. This study illustrates the profound potential of Digital Humanities through the application of statistical methods on two distinct artefact datasets. Specifically, we present the results of an automated minting study of mid-first millennium CE struck and cast ‘Rising Sun’ coinage from mainland Southeast Asia, while subsequently utilizing unsupervised statistical methods on 2D images of 13th–14th-century earthenware ceramics excavated from the precolonial St. Andrew’s Cathedral site in central Singapore. This research offers a comparative assessment showcasing the transformative impact of statistics-based approaches on the interpretation and analysis of diverse archaeological materials and within Digital Humanities overall.

Under the name of “Lua”: revisiting genetic heterogeneity and population ancestry of Austroasiatic speakers in northern Thailand through genomic analysis

BackgroundAustroasiatic (AA)-speaking populations in northern Thailand are of significant interest due to their status as indigenous descendants and their location at the crossroads of AA prehistoric distribution across Southern China, the Indian Subcontinent, and Mainland Southeast Asia. However, the complexity of ethnic identification can result in inaccuracies regarding the origin and migration history of these populations. To address this, we have conducted a genome-wide SNP analysis of 89 individuals from two Lavue and three Lwa-endonym populations. We then combined our outcomes with previously published data to elucidate the genetic diversity and clustering of AA groups in northern Thailand.ResultsOur findings align with existing linguistic classifications, revealing different genetic compositions among the three branches of the Mon-Khmer subfamily within the AA family: Monic, Khmuic, and Palaungic. Although the term “Lua” ethnicity is confusingly used to identify ethnic groups belonging to both Khmuic and Palaungic branches, our genomic data indicate that the Khmuic-speaking Lua living on the eastern side of the region are relatively distant from the Palaungic-speaking Lavue and Lwa populations living on the western side. The Lavue populations, primarily inhabiting mountainous areas, exhibit a genetic makeup unique to the AA family, with a close genetic relationship to the Karenic subgroup of the Sino-Tibetan language family. Conversely, the Lwa and Blang populations, residing in lowland river valleys, display genetic signatures resulting from admixture with Tai-Kadai-speaking ethnic groups.ConclusionUtilizing genome-wide SNP markers, our findings indicate genetic heterogeneity among the Lua, Lavue, and Lwa ethnic groups. The intricate interplay of genetics, cultural heritage, and historical influences has shaped these ethnic communities. Our study underscores the importance of accurate ethnic classifications, emphasizing the use of self-identified endonyms, names created and used by the ethnic groups themselves. This approach respects the AA communities in northern Thailand and acknowledges their significant contributions to advancing our understanding of genetic anthropology.

A multi-gene phylogeny of the Asian kukri snakes (Oligodon Fitzinger, 1826): Sharpening the blade of the second largest serpent radiation (Reptilia: Squamata: Colubridae)

With 90 recognized species, kukri snakes in the genus Oligodon Fitzinger constitute the second largest snake radiation in the world. Oligodon species are collectively distributed across the Asian continent and possess several ecological and morphological attributes that are unique amongst other snakes. Despite their high levels of species richness, evolutionary relationships within Oligodon are poorly understood due to a limited number of samples and genetic markers available in earlier phylogenies. In this study, we assembled the largest molecular dataset of Oligodon to date, which we use to assess the systematics and biogeography of the entire genus. Based on a combination of maximum likelihood and Bayesian phylogenies using fragments of three mitochondrial genes (12 s, 16 s, CytB) and three nuclear genes (Rag1, C-mos, BDNF), we identify eight deeply divergent clades within Oligodon, of which only two correspond with species groupings that were recognized by previous morphological classifications. Four species delimitation methods employed on the mitochondrial portion of the dataset resulted in dramatically divergent estimations of molecular operational taxonomic units (mOTUs). When combined, all four methods support the existence of unrecognized species-level lineages, but also indicate that several other Oligodon species are poorly differentiated genetically and require additional integrative taxonomic research to properly resolve. Based on divergence dating, we demonstrate that Oligodon began to diversify during the early Neogene and hypothesize that the most recent common ancestor of the genus originated in mainland Southeast Asia. We conclude by recognizing eight phylogenetically defined species groups and identify sampling gaps that require further investigation once new data becomes available. This study contributes to a greater understanding of snake evolution on the Asian continent and acts as a baseline for future studies of this speciose genus.

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.

Musa species in mainland Southeast Asia: From wild to domesticate.

Many species are defined in the Musa section within its natural diversification area in Southeast Asia. However, their actual number remains debated as botanical characterisation, distribution and intraspecific variability are still poorly known, compromising their preservation and their exploitation as crop wild relatives of cultivated forms. To address the underexplored Musa diversity in mainland Southeast Asia, at the northern edge of the natural range, 208 specimens were collected in Vietnam, Laos and China, mainly belonging to Musa balbisiana, M. itinerans, M. acuminata and M. yunnanensis. Data on location, morphology, environment and local knowledge were recorded, and leaf samples collected for high-throughput genotyping. This study combines geographical, morphological, and genomic diversity to clarify the taxonomic classification. The collected species exhibit highly distinctive morphologies and genomes, just as they differ in ranges and life traits. Intraspecific genomic diversity was also observed, although not necessarily morphologically perceptible. Mainland Southeast Asia is confirmed as a primary diversification centre for the Musa section. The diversity observed is only partially represented in major international ex situ collections, calling for their urgent enrichment and the promotion of in situ management procedures, for the protection of these threatened species and to better harness their potential in breeding programmes. Although considered wild, the species studied are all affected to varying extents by human use. Musa yunnanensis and M. acuminata subsp. burmannica are the most strictly wild forms, with spontaneous interspecific hybrids first described in this study. Although gathered as fodder, they were only occasionally dispersed outside their endemic zones. Musa itinerans is not cultivated per se, but natural populations are widely exploited, leading to a geographically structured diversity. The diversity of M. balbisiana is widely distributed and geographically structured by human activities. This species should be regarded as domesticated. These various stages, from simple opportunistic gathering to true domestication, shed light on the evolutionary history of today's cultivated varieties.

Regional impacts of solar radiation modification on surface temperature and precipitation in Mainland Southeast Asia and the adjacent oceans.

Solar radiation modification (SRM) has been proposed to temporarily reduce anthropogenic warming. This study presents an assessment of the regional impacts of SRM via solar dimming and stratospheric aerosol injection (SAI) on temperature and precipitation over 0°-30° N and 90° E-110° E, covering Mainland Southeast Asia and adjacent oceans. Using data from the Geoengineering Model Intercomparison Project Phase 6 (GeoMIP6), we examine regional impacts of SRM using three SRM experiments: (1) G6Sulfur, which reduces radiative forcing from the high-emission SSP5-8.5 scenario to the moderate-emission SSP2-4.5 scenario by injecting sulfate aerosols; (2) G6Solar, which similarly reduces radiative forcing from the high-emission to moderate-emission scenarios but by uniformly reducing the solar constant; and (3) G1ext, which reduces radiative forcing from a quadrupled carbon dioxide concentration to pre-industrial levels by uniform solar constant reduction. Our findings show that higher greenhouse gas emissions increase overall precipitation, along with tendencies to have extreme rainfall events and more dry episodes in between. While SRM can partially cool down the surface temperature warming caused by increased greenhouse gas emissions, its effects on precipitation are complex: Solar dimming in G6Solar and G1ext tends to reduce overall precipitation, and tropical sulfate injection in G6Sulfur could lead to further drying in the tropics because of the stratospheric warming associated with the injected aerosols. Different SRM strategies might result in different responses on precipitation.

Biampullisna, a new genus for “Teulisna” uniplaga Hampson (Lepidoptera: Erebidae: Arctiinae: Lithosiini)

A new genus Biampullisna gen. n. is erected to solely include “Teulisna” uniplaga Hampson, 1894 widely distributed in Mainland Southeast Asia, South China (Hainan Island) and the islands of Borneo and Sumatra. A new combination is introduced: Biampullisna uniplaga (Hampson, 1894), comb. n. Adults, as well as male and female genitalia of the type species of the new genus and similar taxa are illustrated.

Quantifying the internal and external drivers of Southeast Asian rainfall extremes on decadal timescales

Rainfall over mainland Southeast Asia experiences variability on seasonal to decadal timescales in response to a multitude of climate phenomena. Historical records and paleoclimate archives that span the last millennium reveal extreme multi-year rainfall variations that significantly affected the societies of mainland Southeast Asia. Here we utilize the Community Earth System Model Last Millennium Ensemble (CESM-LME) to quantify the contributions of internal and external drivers to decadal-scale rainfall extremes in the Southeast Asia region. We find that internal variability was dominant in driving both Southeast Asian drought and pluvial extremes on decadal timescales although external forcing impacts are also detectable. Specifically, rainfall extremes are more sensitive to Pacific Ocean internal variability than the state of the Indian Ocean. This discrepancy is greater for droughts than pluvials which we suggest is attributable to external forcing impacts that counteract the forced Indian Ocean teleconnections to Southeast Asia. Volcanic aerosols, the most effective radiative forcing during the last millennium, contributed to both the Ming Dynasty Drought (1637–1643) and the Strange Parallels Drought (1756–1768). From the Medieval Climate Anomaly to the Little Ice Age, we observe a shift in Indo-Pacific teleconnection strength to Southeast Asia consistent with enhanced volcanism during the latter interval. This work not only highlights asymmetries in the drivers of rainfall extremes but also presents a framework for quantifying multivariate drivers of decadal-scale variability and hydroclimatic extremes.

Incorporating New Datatypes to Enhance Species Delimitation: A Case Study in Rice Paddy Snakes (Homalopsidae: Hypsiscopus).

Homalopsids (Old World Mud Snakes) include 59 semiaquatic species in Asia and Australasia that display an array of morphological adaptations, behaviors, and microhabitat preferences. These attributes make homalopsids an ideal model system for broader questions in evolutionary biology, but the diversity of this understudied group of snakes is still being described. Recognized species diversity in rice paddy snakes (Hypsiscopus) has recently doubled after nearly 200 years of taxonomic stability. However, the evolutionary distinctiveness of some populations remains in question. In this study, we compare mainland Southeast Asian populations of Hypsiscopus east and west of the Red River Basin in Vietnam, a known biogeographic barrier in Asia, using an iterative approach with molecular phylogenetic reconstruction, machine-learning morphological quantitative statistics, and ecological niche modeling. Our analyses show that populations west of the Red River Basin represent an independent evolutionary lineage that is distinct in genetics, morphospace, and habitat suitability, and so warrants species recognition. The holotype of H. wettsteini, a species originally described in error from Costa Rica, grouped morphometrically with the population at the Red River Basin and eastward, and those west of the Red River Basin are referred to the recently described H. murphyi. The two species may have diversified due to a variety of geological and environmental factors, and their recognition exemplifies the importance of multifaceted approaches in taxonomy for downstream biogeographic studies on speciation scenarios.