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The quest for the parent impact structure for Australasian tektites (AAT) has remained without solution for almost a century. The present paper doubts the plausibility of the recently proposed location of the impact site at the Bolaven volcanic field in Southern Laos by showing problems with most of the presented lines of evidence. The geochemical incompatibility of the AAT composition with a mixture of weathered basalts and Mesozoic sandstones that were proposed as source materials of AAT is demonstrated by a two‐component mixing calculation for major element oxides and the Nd‐Sr isotopic system. Deficiency of the basaltic component as a source of Ni, Co, Cr, and 10Be in AAT and inconsistency with trends observed for O and Pb isotopes are shown. The size of the putative crater, conclusiveness of a gravity anomaly identification, signs of complete crater burial by postimpact lava flows, and identification of proximal ejecta blanket are doubted. Remarks on the shortcomings of the current consensus location of an impact site for AAT in Indochina are presented. [ABSTRACT FROM AUTHOR]

This paper continues the publication of Aspidistra species newly discovered in the flora of Vietnam. It includes an illustrated description of A. pentagona, found in the northern part of the country. Detailed analytical color illustrations, data on morphology and ecology, phenology, tentative relationships, distribution and expected conservation status are provided for the discovered species. [ABSTRACT FROM AUTHOR]

Information on the area and spatial distribution of cropland resources is very important for agricultural monitoring and sustainable development. The existing evaluation and analysis of cropland resources mainly focus on the first-class cropland types, and the spatial resolution of cropland cover products studied is low (<30 m), which cannot meet the needs of food security assessment and sustainable analysis of cropland resources. Therefore, in this paper, four published cropland cover products with a spatial resolution of 30 m (GFSAD30SEACE, GLC_FCS30-2015, FROM-GLC2015, and SERVIR MEKONG) are evaluated for consistency and accuracy through area validation, comparison of spatial pattern distribution, and fieldwork data. The results showed that (1) the area and spatial pattern of the four first-class cropland cover types were consistent, especially the GFSAD30SEACE product. However, the area and spatial consistency among different products decreased significantly for the finer type of secondary cropland cover, and the area percentage of rice field was only 3.03%. (2) The spatial inconsistency areas of cultivated land for the four products have different distribution rules under different topographic factors, mainly distributed in the range of elevation (<300 m), slope (2°-15°), and topographic relief (0-10 m). (3) The GFSAD30SEACE product had the highest overall accuracy of 88.33% for the primary type of cropland cover. The overall accuracy was lower for all secondary types of cropland cover, with the SERVIR MEKONG product having the highest overall accuracy (71.64%) and the other products having an overall accuracy of less than 62%. Therefore, future land cover mapping of cropland needs to focus on technical solutions for the classification of fine cropland types. [ABSTRACT FROM AUTHOR]

In this paper, the authors quantitatively investigated the joint impact of the Arctic Oscillation (AO) and El Niño‐Southern Oscillation (ENSO) on vegetation net primary productivity (NPP) over Indo‐Myanmar in boreal winter from 1981 to 2018, and found that there is a significant in‐phase variation between them. When the warm ENSO co‐occurs with the positive AO, the NPP in more than 80% of the grids in the study region significantly increases by approximately 24 gC m−2. For the cold ENSO plus the negative AO, the regionally averaged NPP anomalies are approximately −10 gC m−2, and the local minimum is as low as −60 gC m−2. The combination of AO and ENSO can explain approximately 36% of the total variance of NPP in Indo‐Myanmar. The AO/ENSO linkages to the NPP are very likely due to regional precipitation anomalies through atmospheric circulation. In association with the positive (negative) AO, the Rossby wave, propagating eastward along the subtropical jet stream, brings an anomalous cyclone (anticyclone) over Indo‐Myanmar. This enhances (weakens) Indo‐Myanmar Trough, and resulting in more (less) regional precipitation. During the warm (cold) ENSO, through the Gill‐type response, an anomalous high (low)‐pressure appears in the lower and middle troposphere over Philippine‐South China Sea. The Walker circulation is also weaker (stronger) than normal. These are conducive to anomalous southerly (northerly) winds in Indochina. As a result, in the warm ENSO plus positive AO winters, the mean precipitation anomaly in Indo‐Myanmar increased by 27% as averaged for five data sets. In contrast, when the cold ENSO co‐occurs with negative AO, the precipitation is significantly reduced where the largest anomaly exceeds 100 mm in the ERA5. The precipitation changes are consistent with the local NPP anomalies, whereas the temperature does not seem to be a dominant limiting factor. Plain Language Summary: Vegetation is closely dependent on regional climatic conditions such as temperature and precipitation, whereas these meteorological elements are sensitive to large‐scale climate factors. Therefore, it is necessary to explore the vegetation drivers and underlying physical mechanisms. In this research, we focused on investigating the joint impact of the Arctic Oscillation (AO) and El Niño‐Southern Oscillation (ENSO) on vegetation net primary productivity (NPP) over Indo‐Myanmar in boreal winter from 1981 to 2018, the results show that the combination of AO and ENSO can explain approximately 36% of the total variance in regional NPP. The AO/ENSO linkages to the NPP are very likely due to regional precipitation anomalies through atmospheric circulation. In association with the positive (negative) AO, an eastward Rossby wave propagating along the subtropical jet stream brings an anomalous cyclone (anticyclone) over Indo‐Myanmar. During the warm (cold) ENSO, a southerly (northerly) wind anomaly prevails over Indochina via the Gill‐type response and weaker (stronger) Walker circulation than normal. As a result, when the warm (cold) ENSO co‐occurs with the positive (negative) AO winters, Indo‐Myanmar could experience more (less) precipitation than normal, which can lead to more NPP here. Key Points: There is a significant and robust in‐phase variation between the Arctic Oscillation (AO)/El Niño‐Southern Oscillation (ENSO) and net primary productivity (NPP) over Indo‐Myanmar in boreal winterThe combination of AO and ENSO can explain 36% of the total variance in NPPPrecipitation plays a critical bridge in teleconnection between AO/ENSO and local NPP and explains nearly 40% of the total variance in NPP [ABSTRACT FROM AUTHOR]

Vietnam contains complex faults coupled with a diffuse igneous province that has been active since the mid-Miocene. However, existing fault maps demonstrate little consensus over the location of Neogene basalt flows and relative ages of mapped faults, which complicates interpretations of tectonic model for the evolution of Indochina. This paper identifies discrete tectonic blocks within Vietnam and aims to define the Neogene-Recent tectonic setting and kinematics of south-central Vietnam by analyzing the orientation, kinematics, and relative ages of faults across each block. Fault ages and relative timing are estimated using cross-cutting relationships with dated basalt flows and between slickenside sets. Remote sensing results show distinct fault trends within individual blocks that are locally related to the orientations of the basement-involved block-bounding faults. Faults observed in the field indicate an early phase of dip-slip motion and a later phase of strike-slip motion, recording the rotation of blocks within a stress field. Faulting after the change in motion of the Red River Fault Zone at -16 Ma is inferred, as faults cross-cut basalt flows as young as -0.6 Ma. Strike-slip motion on block-bounding faults is consistent with rotation and continuous extrusion of each block within south-central Vietnam. The rotation of the blocks is attributed to the "continuum rubble" behavior of small crustal blocks influenced by upper mantle flow after the collision between India and Eurasia. We infer a robust lithospheric-asthenospheric coupling in the extrusion model, which holds implications for other regions experiencing extrusion even in the absence of a free surface. [ABSTRACT FROM AUTHOR]

This paper examines the changes of El Niño–Southern Oscillation (ENSO) associated winter rainfall relationship in Southeast Asia (SEA) in the historical period (1981–2010) and future period (2071–2100) based on the Coupled Model Intercomparison Project Phase 6 (CMIP6) models simulations. Twenty general circulation models (GCMs) are chosen from the Scenario Model Intercomparison Project (ScenarioMIP) highest emission scenario—Shared Socioeconomic Pathway (SSP) 5‐8.5. This study focuses only on the GCMs that have been able to replicate the consistent associated patterns observed, referred to as "teleconnection‐consistent models" (TCMs). During historical period, ENSO has significant negative association with SEA winter rainfall, particularly over Indochina mainland, Maritime Continent (MC) and northern Borneo. The significant negative‐associated teleconnection affected area has increased under future climate, particularly over southern part of South China Sea (SCS). The weakening of south westerlies at Western North Pacific (WNP) centred near 20°N reduces the moisture transport from Indochina into south of China, increase the negative correlated affected area in the SEA regions above equator. The northeasterlies/easterlies that prevailed from the WNP anticyclone (AC) brings significant moisture flux into southern Borneo, causing increment of significant positive‐associated moisture flux convergence to that region. The weakening of upward motion in TCM results in less warm and moist air rising over SEA MC, reducing the rainfall availability. The 1° eastward expansion of WC downward branch eastern edge leads to suppression of convective activities, increasing the dry affected area. The results suggest that the ENSO has a larger influence on the negative‐associated SEA rainfall and atmospheric circulation in the December–January–February (DJF) late‐21st century when compared to the 1980–2010. [ABSTRACT FROM AUTHOR]

Continental‐scale shear zones in Indochina record Cenozoic tectonic processes in SE Asia. Previous extrusion models link these shear zones to northward indentation of the Indian continent and conflict with distributed Oligocene conjugate strike‐slip pairs, formed by E‐W‐directed compression (present coordinates). This paper presents evidence of Oligocene shearing along the Mogok Metamorphic Belt in Myanmar, the western boundary of the Indochina block. The Kyanigan quarry at northern Mogok Metamorphic Belt exposes paragneiss, marble and quartzite schist with E‐W striking, which would be dragged from N‐S striking foliations of the main Mogok Metamorphic Belt by right‐lateral shearing of the brittle Sagaing Fault. After restoration, right‐lateral shearing 'σ' structures, cored with garnet, in paragneiss in the Kyanigan quarry are consistent with 'σ' and 'δ' structures in the Moulmein granitic mylonite to the south. U–Pb ages of metamorphic zircon of a sheared paragneiss and a leucogranite, cross‐cutting shear foliation in the Kyanigan quarry, and a biotite 39Ar‐40Ar age of mylonite at Moulmein constrain dextral shearing to 33–25.4 Ma, coeval with other 31–24.5 Ma shear zones in Indochina. The eleven NW‐striking left‐lateral shear zones and N‐S to NE‐striking right‐lateral shear zones define Oligocene conjugate fault patterns in Indochina. After restoration of ~80–45° clockwise rotation, these Oligocene conjugate shear zones, coupled with the anticlinal configuration of the Xuelongshan and Doi Inthanon‐Doi Suthep domes, reflect approximate N–S‐directed shortening. These structures to the north with coeval Myanmar‐Sumatra magmatic arc to the south demonstrate that they correspond to back‐arc contraction during northward subduction of the Indian Ocean. Oligocene continental‐scale intra‐continental shearing may be triggered by syn‐subduction compression in SE Asia. [ABSTRACT FROM AUTHOR]

Modelling rainfall extremes and dry periods over the Southeast Asia (SEA) region is challenging due to the characteristics of the region, which consists of the Maritime Continent and a mountainous region; it also experiences monsoonal conditions, as it is located between the Asian summer monsoon and the Australian summer monsoon. Representing rainfall extremes is important for flood and drought assessments in the region. This paper evaluates extreme rainfall climatic indices from regional climate models from CORDEX Southeast Asia and compares them with the results of high‐resolution global climate models with a comparable spatial resolution from the HighResMIP experiment. Observations indicate a high intensity of rainfall over areas affected by tropical cyclones and long consecutive dry day periods over some areas in Indochina and the southern end of Indonesia. In the model simulations, we find that both coupled and sea surface temperature‐forced HighResMIP model experiments are more similar to the observations than CORDEX model results. However, the models produce a poorer simulation of precipitation intensity‐related indices due to model biases in the rainfall intensity. This bias is higher in CORDEX than in HighResMIP and is evident in both the low‐ and high‐resolution HighResMIP model versions. The comparable performances of HighResSST (atmosphere‐only runs) and Hist‐1950 (coupled ocean–atmosphere runs) demonstrate the accuracy of the ocean model. Comparable performances were also found for the two different resolutions of HighResMIP, suggesting that there is no improvement in the performance of the high‐resolution HighResMIP model compared to the low‐resolution HighResMIP model. [ABSTRACT FROM AUTHOR]

This paper examines the French presence and its effect on the emergence of Cambodian nationalism (1920-1937). There were serious measures on the part of the French to change the general conditions in the Cambodian kingdom for the better, but because the French continued their repressive methods against the Cambodians that gave rise to nationalist feelings against them. The turmoil of political and economic conditions during the years (1927-1935) helped the emergence of the Hindu Communist Party during the year 1930 in Indochina. The establishment of the Nagravata newspaper and its impact on Cambodian society (1936-1937) was not against the French presence in Cambodia but on the contrary, the other Cambodian newspaper and publications were promoting that the Cambodians (Khmer) viewed the French as protectors against their neighbors, and that the main enemy was the Vietnamese, but at The establishment of the Cambodian Youth League began to demand Cambodian rights from French colonialism. [ABSTRACT FROM AUTHOR]

The Truong Son orogenic belt (TSOB) is one of the most important orogenic belts in the Indochina block. There are numerous mafic to felsic intrusions in the Early Paleozoic caused by the Tethyan orogeny. However, the tectono-magmatic evolution of the TSOB in the Early Paleozoic is still unclear. In this paper, zircon U-Pb dating, whole-rock geochemistry, and the Sr-Nd isotopic data of the Early Paleozoic magmatic rocks have been systematically investigated to explore the petrogenesis and tectonic significance of these rocks in the TSOB. Based on our new results integrated with previous geological data, four major tectono-magmatic episodes are identified. (1) The Middle Cambrian (~507 Ma) is the early stage of northward subduction of the Tamky-Phuoc Son Ocean. (2) The Early Ordovician to Middle Ordovician (483–461 Ma) is the main subduction stage of the Tamky-Phuoc Son Ocean. The intrusive rock associations imply the closure of the Tamky-Phuoc Son Ocean. (3) The Late Ordovician to Early Silurian (461–438 Ma) is the collision stage of the Kontum massif and Truong Son terrane. (4) The Early Silurian to Late Silurian (438–410 Ma) is the late stage of collision accompanied by slab roll-back. [ABSTRACT FROM AUTHOR]

Purpose - This paper focuses on the evolution of and changes in French colonial architectural designs over time in terms of the use of vernacular architectural features of Vietnam. Design/methodology/approach - It first examines the underlying principles of spatial compositions behind traditional vernacular architecture, thus revealing vernacular architectural values that have survived from the past. Styles of vernacular houses differ by region; thus, their unique spatial characteristics are analyzed by selecting the typical houses in each region. The study also illuminates ecological features and technical norms tailored to the local climate and Vietnamese traditional architecture. It examines how local and regional characters of vernacular houses affect the developments and changes in the French colonial public buildings in Vietnam, forming an identity that represents an eclectic Indochina style with the adaptation of local discourses on climate. Findings - The Vietnamese have developed unique architectural styles that are inextricably linked to their identities, cultures, climates and livelihoods - for example, vernacular houses. Although at the beginning of the colonial period, the French imported their styles, decorations and details, which were foreign to the Vietnamese, later, they perhaps realized that such direct import was no longer suitable for the natural and socio-cultural situation of the colony. Toward the end of the colonial period, it is noticeable that French colonial architects gradually started using local design principles. Research limitations/implications - Although many existing buildings can be further added for the discussion, we limit a few cases, due to the length of the paper. Social implications - This paper proves that toward the end of the colonial period, colonial architecture in Vietnam became increasingly localized, adapting to the local environment and climate. The buildings during the period were gradually associated with Vietnamese culture and sentiment. Originality/value - Although few papers deal with the vernacular architecture in Vietnam with regard to local climate and regional characteristics, there are no paper that related the vernacular Vietnamese houses to influence the French colonial designs in Vietnam. Therefore the paper has value and significance. [ABSTRACT FROM AUTHOR]

After entering Indochina, Japan retained the French-Indochina colonial administration and started controlling Indochina through this administrative system. The biggest expectation of Japan towards French-Indochina was the guaranty of rice supply to satisfy requirements and in addition to take a stand in preparation for southward advance and the pursuance of the Second Sino-Japanese War. However, at that time, the mechanisms of rice distribution within French-Indochina were held by Overseas Chinese merchants who expanded the Anti-Japanese movement. As overseas Chinese had extensive economic power but held sensitive political positions in Indochina as "Asiatiques Étrangers", Japan designated that gaining the co-operation of the Overseas Chinese was an important task in order to guarantee food supply and to construct the Greater East Asia Co-prosperity Sphere. By examining the actions and reactions on both sides (Japan and France) from political and economic view-point with regard to overseas Chinese, this paper aims to clarify the nature of this relation -- a competitive relation under the form of co-operation, and there is a hint of contempt, compromise and opposition between two sides. [ABSTRACT FROM AUTHOR]

This paper continues the publication of Aspidistra species newly discovered in the flora of Vietnam. It includes illustrated diagnosis of two species new to science, A. liliiflora and A. sessilistigma found in northern and central parts of the country. Detailed analytical color illustrations, data on morphology, ecology, phenology, tentative relationships and distribution are provided for both discovered species. [ABSTRACT FROM AUTHOR]

This paper attempts to test whether the Covid-19 pandemic has an impact on the linkages of the metal futures market of India and China. Taking Daily closing prices from 4 Jun 2016 to 23 Apr 2021 for the seven metals, including copper, aluminum, zinc, lead, nickel, gold, and silver, have been included in the study in the pre-announcement and post-announcement of covid-19 as a pandemic. The autoregressive distributed lag (ARDL) bound test and Johansen cointegration test report no cointegrating relationship between the markets for all the metal futures before the covid period. There is no change in the absence of cointegration in the post-announcement period of Covid-19. Similarly, Granger causality results report no change in the short-run relationship between the metal futures markets except for silver futures. The results have implications for portfolio managers and investors looking to reshuffle their portfolios in the light of changes in the market due to the covid-19 pandemic. [ABSTRACT FROM AUTHOR]

India and China have been at the top of the exporter, importer, producer and consumer economies. The two neighbouring countries provide the largest market in the world. They also share a similar history of development of their commodity derivatives markets. This paper aims to examine the direction of causality and spillover effect between the metal futures markets of the two economies. The analysis is done for metals such as copper, aluminium, zinc and gold in the period 2009 - 2020 by using Granger causality and Dynamic Conditional Correlation -GARCH (DCC-GARCH) models. The gold futures at the Multi Commodity Exchange (MCX) have a unidirectional causality on the gold futures traded at Shanghai Futures Exchanges (SHFE), unlike other metals having bidirectional causality. Similarly, GARCH results report only long-term volatility spillover for gold futures returns, while for the base metals, both short-term and long spillover exist. The findings indicate that the Indian metals futures market has started to influence the Chinese metal futures. The results have important implications for policymakers, regulators, industrialists and offshore traders of physical commodities in hedging their positions. [ABSTRACT FROM AUTHOR]

The magmatic rocks of the Ben Giang-Que Son complex exposed in the southern part of the Truong Son belt have petrographic compositions including gabbro, gabbrodiorite, granodiorite, and granite. Geochemically, the magmatic rocks are of subalkaline affinity and belong to the high-K calc-alkaline series. All analyzed samples contain hornblende and biotite as mafic minerals and are defined as metaluminous with a aluminum saturation index of <1.1. Chondrite-normalized rare earth element diagrams are characterized by fractionation between light and heavy rare earth elements and show small to moderate negative Eu anomalies (Eu/Eu* = 0.81–0.44). Primitive mantle-normalized trace element patterns exhibit enrichment in LILEs such as Rb, K, U, and especially Pb and depletion of HFSEs (Nb, Ta, and Ti), indicating arc-magma. The BG-QS gabbro and gabbrodiorite have low Cr, Co, and Ni and display enrichment in 87Sr/86Sr (0.7084 to 0.7147), ꜪNd(t) (−0.5 to −1.9), and positive ꜪHf(t) (+2.4 to 4.5), suggesting generation from the enriched mantle source. The BG-QS diorite and granodiorite contain small mafic enclaves, have a wide range of SiO2 contents and enrichment in Sr-Nd isotopes (87Sr/86Sr = 0.7109–0.7178; ꜪNd(t) = −3.3 to −3.7), and display high Mg# (43–51). All these features indicate that they were formed by the mixing of magmas, which originated from an enriched mantle source and the pre-existing juvenile mafic lower crust. The whole-rock Nd and zircon Hf model ages are of 1160–760 Ma. The Ben Giang-Que Son complex yields LA-ICP-MS zircon U-Pb ages of 285 ± 3.1 and 278 ± 3.5 Ma that corresponds to the Cisuralian epoch (early Permian), which is linked to the subduction and amalgamation of the Indochina and South China blocks due to the closing a branch of the Paleotethys along the Song Ma suture. [ABSTRACT FROM AUTHOR]

The razor clam genus Novaculina is a secondary marine-derived freshwater taxa within the otherwise exclusively marine family Pharidae. Novaculina currently comprises four valid species that are distributed allopatrically across several drainages in Asia. We employed an integrated approach, combining morphology and molecular phylogenetic analyses to elucidate the taxonomic placement of members within this genus. The multi-locus phylogenetic trees based on cytochrome c oxidase subunit I (COI), 16S rRNA and 28S rRNA gene sequences demonstrate that Novaculina is polyphyletic. Specimens identified as N. siamensis form a distinct clade that is not sister group to other currently recognised congeners. Furthermore, morphological examination reveals distinct characteristics in 'N. siamensis', namely a fused, fringed siphon, in contrast to the separated, smooth siphons observed in other species. Based on these findings, we propose the establishment of a new genus, Cenonovaculina gen. nov., to accommodate 'N. siamensis'. The new genus is distinguished from other genera in having a short shell, deep pallial sinus, elongate, oval to bean-shaped anterior adductor scar and long fused siphons surrounded by conical tentacles. [ABSTRACT FROM AUTHOR]

The distribution of known Syzygiella taxa in Indochina was reviewed. Currently, four species are known in Indochina: S. autumnalis, S. elongella, S. nipponica, and S. securifolia. This genus is reported for the first time in the flora of Cambodia, and S. securifolia is newly recorded for Vietnam. Herein, a description of oil bodies for S. securifolia is provided for the first time. A morphological description of the species and intravital photographs, as well as line-art illustrations, are provided along with the identification key to the Syzygiella taxa known in Indochina. A comparison of the climatic parameters of the collection sites for four known species showed that three of them occupy a relatively marginal position in the flora of Indochina as a whole and are known from colder biomes on the very northern edge of the peninsula. The locations of Syzygiella securifolia are scattered not only on the geographical map of Indochina but also on the bioclimatic scatterplot; these locations are likely an underestimation of the distribution of this taxon in Indochina, although it is generally rare worldwide. A comparison of lists of liverworts across the countries of Indochina will help identify groups of taxa for further targeted searches with the purpose of obtaining more comprehensive knowledge of the biodiversity of still poorly studied Indochina countries. [ABSTRACT FROM AUTHOR]

Simple Summary: Mecoptera, commonly known as scorpionflies and hangingflies, are an interesting, but small, and rarely-observed order of moderately-sized insects, with at least 22 species in Thailand. These insects typically prefer cool, moist mature forested habitats with broken sunlight, often on low vegetation bordering small mountain streams. They are poor fliers thus limiting their ability to disperse. For these reasons, they serve as a valuable bioindicator for monitoring changes in climatic and forest communities. However, no ecological study has previously been conducted for this insect group. This study exploits data from Project Tiger, where specimens were collected using Malaise and pan traps from 18 national parks across Thailand to characterize the biodiversity of Mecoptera with a focus on the influences of elevational and climatic factors. We found 21 species in total with 52% of them being specific to particular regions. Negative correlations between species richness and abundance of Mecoptera with both elevation and temperature were observed, suggesting a predominance of species in mid-altitude areas with a peak in the rainy season (21 species) followed by the hot (10 species) and cold (7 species) seasons. We suggest that the narrow distribution and preference for mid-altitude make Mecoptera particularly vulnerable to global warming, raising urgent conservation concerns. Ecological analyses of the small and lesser-known insect order Mecoptera in Thailand are presented. Specimens were collected monthly over a period of 12 consecutive months, using both Malaise and pan traps, from 29 sampling sites located in 18 national parks throughout Thailand. A total of 21 species in four genera were identified from 797 specimens, including Panorpa (1 species), Neopanorpa (18 species), Bittacus (1 species), and Terrobittacus (1 species), with the latter genus representing a new genus record to Thailand. Neopanorpa harmandi, N. siamensis, N. byersi, and N. malaisei were the most abundant species, representing 27.4%, 11.3%, 10.3% and 8.8% of the total specimens, respectively. The species with the highest frequency, as indicated by the high percentage of species occurrence (%SO), was N. siamensis (51%), followed by N. byersi (34%), N. harmandi (34%), N. spatulata (27%), and N. inchoata (27%). Eleven species (52%) exhibited specific regional occurrences. N. tuberosa and N. siamensis had the widest distribution, being found in almost all regions except for western and southern regions for the first and second species, respectively. The seasonal species richness of Mecoptera was high during the rainy season in the northern, northeastern, central, eastern, and western regions, with the highest richness observed in July (15 species), followed by the hot (10 species) and cold seasons (7 species), while there was no significant difference in species richness between seasons in the southern region. Multiple regression models revealed a negative association between species richness and abundance of Mecoptera with both elevation and temperature, and a positive association between rainfall and species evenness. It is predicted that climatic changes will have a detrimental effect on the mecopteran community. The results of this study enhance the understanding of the ecological aspects of Mecoptera, offering crucial insights into its biodiversity and distribution, which are vital for conservation and forest management. [ABSTRACT FROM AUTHOR]

In November 1998, guided by Prof. Trấn Ninh we revisited the Tam Đảo mountain range, extensively researched by him before. Since than it was converted into a National Park, with areas stretching to three provinces, Vĩnh Phúc, Thái Nguyên, and Tuyên Quang. The previous collections indicated that many more novelties can be expected from there. As a result, we collected 38 epiphyllous liverwort species. Among these 6 were new to the flora of Vietnam: Cololejeunea fructu-marginata, C. papillosa, C. spathulifolia, Colura bisvoluta, Lejeunea dipterota and Microlejeunea sechuanensis. One species is new to science: Cololejeunea dinhensis. Furthermore, Cololejeunea rotundilobula proved to be a new synonym of Cololejeunea sigmoidea. [ABSTRACT FROM AUTHOR]

A new bush frog species is described from Yunnan, China, based on phylogenetic analyses, species delimitation analyses, and morphological comparisons. Raorchestes hekouensis sp. nov. is distinguished from all other congeners by a combination of 11 morphological characters. The new species brings the current number of Raorchestes species in China to ten, nine of which are distributed in Yunnan. Molecular analyses supported an unnamed lineage previously recorded as “Raorchestes gryllus” in northern Vietnam. Further studies including additional samples are necessary to clarify the species diversity and boundaries of Raorchestes in China and Indochina. [ABSTRACT FROM AUTHOR]

Indochinese species of the genus Bolbelasmus (Coleoptera, Geotrupidae, Bolboceratinae) are reviewed. Three new species, Bolbelasmus chifengi Wang & Li, sp. nov., Bolbelasmus concavisuturalis Li & Wang, sp. nov. and Bolbelasmus yutangi Li & Wang, sp. nov., are described and illustrated. An annotated checklist and modified key to species of the genus are provided. Information for each species in the checklist includes literature review, synonymy, distribution and type locality. [ABSTRACT FROM AUTHOR]

Seed germination is among the most crucial and vulnerable stages in plant life cycles. Quercus marlipoensis is a critically endangered sclerophyllous oak. Only one population has ever been found worldwide in the tropical montane cloud forests of southeastern Yunnan, China, and it has shown difficulties with regeneration. However, its seed biological traits and key restrictive germination factors remain unknown. We investigate the impacts of scarification, temperature, and water potential on the seed germination of Q. marlipoensis. Results show that the seeds show typical epicotyl dormancy. The seed germination increased when removing part or all of the pericarp and part of the cotyledon (one-third and two-thirds). The seeds can germinate at 5 to 30 °C, but the highest T50 was achieved at 25 °C. When the water potential decreased from 0 to −1.0 MPa, the germination rate decreased but the germination time increased. Q. marlipoensis seeds are typically recalcitrant and highly sensitive to moisture loss, but the species can tolerate animal predation and low germination temperatures. The more frequent climatic extremes and droughts in the Indo-China region will severely degrade its natural habitats. Therefore, ex situ conservation to preserve its germplasm and introduce seedlings into a suitable habitat are essential for its conservation management. [ABSTRACT FROM AUTHOR]

Following the termination of seafloor spreading in the South China Sea (SCS) basin, abundant intraplate volcanism widely spreads in the Indochina block, SCS basin, and Leiqiong area, forming the Southeastern Asian Basalt Province (SABP). The geodynamic origin of the SABP has long been enigmatic and debated. Here, we present a high‐resolution 3‐D upper mantle S‐wave velocity model in the region by conducting earthquake‐based surface wave tomography with seismic data collected across Southeast Asia. The resultant images depict a plume‐like structure beneath the central area of the SABP, characterized by a continuous, sub‐vertical low‐velocity column in the upper mantle. Our new findings, combined with previous geochemical and geodynamic evidence, suggest that the extensive post‐spreading intraplate volcanism within the SABP is likely induced by this focused mantle upwelling, which could be further traced down to the core‐mantle boundary as inferred by existing global velocity models. Plain Language Summary: The well‐known Southeastern Asian Basalt Province (SABP), which covers an extensive area of the South China Sea (SCS) and surroundings, is characterized by voluminous volcanism after the cessation of seafloor spreading in the SCS basin. However, the geodynamic mechanism responsible for the formation of the SABP remains debated and not well understood. In this study, we build a high‐resolution 3‐D seismic velocity model in the region utilizing multiple sources of seismic data collected throughout Southeast Asia. We find a distinct plume‐shaped low‐velocity anomaly in the upper mantle beneath the central region of the SABP. Combining with previous geochemical and geodynamic research results, we interpret that the abundant intraplate volcanism within the SABP may be contributed by the underlying focused mantle upwelling. This mantle upwelling, as evidenced in previous global seismic velocity models, could be further traced down to the core‐mantle boundary (∼2,900 km below the Earth's surface). Our tomographic images provide valuable insights into the origin and mantle dynamics related to the young intraplate volcanism that occurred in Southeast Asia. Key Points: A high‐resolution 3‐D upper mantle S‐wave velocity model surrounding the South China Sea is constructedA continuous, low‐velocity column is imaged beneath the central region of the Southeastern Asian Basalt ProvinceThe post‐spreading intraplate volcanism within the Southeastern Asian Basalt Province is likely induced by the focused mantle upwelling [ABSTRACT FROM AUTHOR]

With the establishment of the Indochinese Federation, the French colonial government implemented policies to develop the transport system in the colonies, connecting Laos with other regions in the Indochinese Federation. Previous studies have mainly focused on demonstrating the development of the transport network in Vietnam or highlighting the limitations of the French colonial government in investing in the development of transport in Laos. This article aims to redefine the role of the French in developing the transport network and infrastructure in Laos in order to break its isolation and associate this country with the rest of the Indochinese Federation. These policies had a long-term influence on the development of modern Laos when the development of Lao trade shifted from dependence on the Mekong River and the port of Bangkok to commercial circulation by many transport services on many different transnational roads directed towards the ports of Indochina. [ABSTRACT FROM AUTHOR]

Opening of the South China Sea (SCS) was triggered by the breakup of south-eastern Eurasia and the southward drifting of the Palawan-Reed Bank microcontinent, as various prior studies have suggested. The young, moderately magmatic, rifted northern margin of the SCS is vital for investigating the relationship among magmatism, rheology, and structural evolution. This paper integrates satellite gravity anomaly, elevation/bathymetry, geoid, and seismic velocities to investigate continental breakup, magmatism, and rifting beneath the South China Sea. Source depths of 146, 31.5, and 8 km derived from the spectrum of Bouguer gravity anomalies suggest the average depths of the lithospheric base, continental, and oceanic crustal bases, respectively. Correspondingly, gravity Moho ranges from 8 km beneath the rifting center of SCS to 42 km in the Indo-China block. It is worth mentioning that the isostatic Moho from the Airy and flexural models were highly correlated with gravity Moho with correlation coefficients of ∼1. From the ratio between geoid and topography and our estimate of the vertical tectonic stress, the seamounts and reefs (Shuangfeng Basin: SB, Reed Bank: RB, Macclesfield Bank: MB) have a deep compensation depth. In contrast, the other parts (Manila Trench: MT, Phu Khan Basin: PK, East Sub Basin: ESB) have a smaller depth of compensation. 2D gravity modelling suggests the crustal thinning of the oceanic basin, and the thickening of the continental boundary implies the opening of the SCS, which is connected and happened at the same time as the northern subduction of the proto-SCS. The Gravity modelling also suggests a large rifting event within the lithosphere that favors mantle upwelling. [Display omitted] • Crustal structure and isostatic nature of the South China Sea are examined. • The compensation depth under Seamounts/reefs is deeper than the other parts of the South China Sea. • 2D gravity modelling suggests large lithosphere rifting events that favor mantle upwelling. [ABSTRACT FROM AUTHOR]

The parent impact crater of Australasian tektites has not been discovered so far, but a consensus has been accepted on its location in a wider area of Indochina. Recently, an alternative location has been suggested in the Badain Jaran Desert (BJD), Northwest China. Employing gravity and magnetic data derived from satellites, possible presence of an impact structure in BJD is investigated. The gravity parameters include the free air gravity disturbance, its vertical derivative component and total horizontal gradient (THG), strike alignment (SA), and Bouguer anomaly with its first vertical derivative and tilt angle. The magnetic parameters include the anomalous total magnetic field (TMF), its reduced to the pole transformation (RTP), the first vertical derivative of the TMF vertical component (Bzz), tilt angle (TA), and logistic total horizontal gradient (LTHG). Both the gravity and magnetic indicators support the presence of the impact structure. Gravity parameters display typical annular gravity highs circumscribing a gravity low. SA analysis reveals preferred parallel directions, implying the susceptibility of special zones to the impact shock waves, both within and beyond the rim. TMF reveals a large magnetic anomaly in the southern part of the proposed crater, and RTP displaces and restricts it further into the rim. Bzz weakens the long wavelength anomalies, amplifies the superficial ones, and separates them horizontally. TA and LTHG delineate the deep-seated and shallow magnetic signals related to the peak and border magnetization, respectively. [ABSTRACT FROM AUTHOR]

Although it is commonly thought that the war in Laos ended in 1975 when the communist Pathet Lao took over the country, in fact the takeover stirred up considerable military and political opposition, leading to civil war. For a variety of reasons, the conflict diminished in the 1990s and 2000s. The improved security situation allowed the government to adopt a new policy allocating large-scale land concessions for use in developing commercial plantations. These concessions inflicted social and environmental violence on the people who lost their land. These two types of violence in Laos, war and dispossession, are linked more closely than is generally recognized. [ABSTRACT FROM AUTHOR]

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The new genus Pumatiracia gen. nov. is described to accommodate a new species, P. venosa gen. et sp. nov. from Pu Mat National Park in Vietnam. The new genus is placed in the subtribe Parahiraciina of the Parahiraciini. It is compared with the genera Laohiracia Constant, 2021, Macrodarumoides Che, Zhang et Wang, 2012, Pseudochoutagus Che, Zhang et Wang, 2011, and Rostrolatum Che, Zhang et Wang, 2020 with which it shares possessing an elongate head. Illustrations of habitus, details, and male genitalia are given as well as a distribution map and photographs of the habitat. Laohiracia acuta Constant, 2021 is recorded for the first time from Vietnam, Pu Luong National Park; living specimens and habitat are illustrated, and the distribution map updated. The Parahiraciini fauna of Vietnam now comprises 14 species belonging to 11 genera. [ABSTRACT FROM AUTHOR]

Aim: Understanding the biotic and abiotic mechanisms underlying the generation and maintenance of biogeographic transitions represent long‐standing topics in evolutionary biology. The Isthmus of Kra (IOK) divides Sundaland and Indochina and constitutes a poorly characterized terrestrial biogeographic transition. Here we looked at population genetic structure of three species that are distributed across the IOK to gain insights into the drivers that have shaped this transition and regional diversification patterns. Location: Tropical east Asia: Sundaland and Indochina. Taxa: Callosciurus caniceps, Tamiops mcclellandii, and Dremomys rufigenis‐ornatus species complex (Mammalia: Rodentia: Sciuridae). Methods: We generated complete mitogenomes and sequences of 11 nuclear intron fragments from 61 and 67 museum specimen samples, respectively. We assessed population structure by constructing Maximum Likelihood mitogenome phylogenies (IQTREE2), and nuclear marker haplowebs and conspecificity matrices (HaplowebMaker and CoMa). We estimated divergence dates through Bayesian phylogenetic inference (BEAST2) and put these results in the context of climatic and geological history. Results: High levels of mitochondrial and nuclear divergence were identified across the IOK in all three squirrels. Lineage turnover was consistent with the two major mammal species distribution transitions near the Kangar‐Pattani Line and at the juncture between the Thai‐Malay peninsula and the mainland. Divergence of mitochondrial lineages across Kra was estimated in the late Pliocene/ early Pleistocene for all three taxa. Older Miocene/Pliocene divergences were estimated within Indochina in D. rufigenis‐ornatus and T. mcclellandii, which were paraphyletic. Main Conclusions: Sundaic and Indochinese populations have possibly diverged in allopatric habitat refugia in or around mountains during periods of increased aridity and evergreen forest contraction. Ecological differences and/or topography might have influenced genetic differentiation during periods of rainforest expansion. Alternative hypotheses remain to be tested with more informative nuclear markers and additional geographic sampling. [ABSTRACT FROM AUTHOR]

Numerous insects including pests and beneficial species undertake windborne migrations over hundreds of kilometers. In East Asia, climate-induced changes in large-scale atmospheric circulation systems are affecting wind-fields and precipitation zones and these, in turn, are changing migration patterns. We examined the consequences in a serious rice pest, the brown planthopper (BPH, Nilaparvata lugens) in East China. BPH cannot overwinter in temperate East Asia, and infestations there are initiated by several waves of windborne spring or summer migrants originating from tropical areas in Indochina. The East Asian summer monsoon, characterized by abundant rainfall and southerly winds, is of critical importance for these northward movements. We analyzed a 42-year dataset of meteorological parameters and catches of BPH from a standardized network of 341 light-traps in South and East China. We show that south of the Yangtze River during summer, southwesterly winds have weakened and rainfall increased, while the summer precipitation has decreased further north on the Jianghuai Plain. Together, these changes have resulted in shorter migratory journeys for BPH leaving South China. As a result, pest outbreaks of BPH in the key rice-growing area of the Lower Yangtze River Valley (LYRV) have declined since 2001. We show that these changes to the East Asian summer monsoon weather parameters are driven by shifts in the position and intensity of the Western Pacific subtropical high (WPSH) system that have occurred during the last 20 years. As a result, the relationship between WPSH intensity and BPH immigration that was previously used to predict the size of the immigration to the LYRV has now broken down. Our results demonstrate that migration patterns of a serious rice pest have shifted in response to the climate-induced changes in precipitation and wind pattern, with significant consequences for the population management of migratory pests. [ABSTRACT FROM AUTHOR]

The study of the flora located in the central part of the Hoàng Liên Sơn Range in the northern region of Indochina has revealed 279 species of liverwort and hornwort, 26 of which are newly reported for the flora of Vietnam. The uniqueness and peculiarity of the studied flora are explained by the significant altitudinal range in the area treated and its position in the contact zone of the Sikang-Yunnan floristic province of the East Asian Floristic Region with the Indochina Floristic Region. The checklist includes data on the distribution of each species in the studied region, habitats, and accompanying taxa. The high disunity of the regional floras of the southern tip of the East Asian region compared to the lesser disunity of the regional floras in the north of the East Asian region is shown. In general, the studied flora possess Sino-Himalayan mountain subtropical characteristics with the large participation of tropical elements. [ABSTRACT FROM AUTHOR]

The southern spread of rice agriculture is of great academic interest. Although it already has a broad chronological framework, newly introduced rice use and its impact on local subsistence and ecological systems are still unclear. In this study, we explore these issues by analysing phytoliths recovered from continuous sediments of Cave No. 4 at the Nanshan site in Fujian Province, together with evidence from surrounding sites. The results show that rice was introduced into southeast China at 7,500 cal. yr BP, but the dominance of the hunting-gathering system was not challenged until later, between 5,000 and 3,500 cal. yr BP, when cultivation of rice, together with foxtail and broomcorn millets, was widely practiced in the region. This suggests that mixed farming in Southeast China, likely originating around the middle Yangtze River, became widespread and gradually systematic during the previous two-millennium adoption. This rice-millet mixed agricultural system changed the former hunting-gathering subsistence system, promoting the agriculturalization process, cultural prosperity and population growth, thus providing a solid basis for rice expansion and cultural migration to Southeast Asia. [ABSTRACT FROM AUTHOR]

Understanding and predicting extreme weather and climate are ultimately important for adaptation and resilience. Here, we assess the prediction skills of frequency of summer extreme hot days (SEHDs) in the Asian monsoon region (AMR) by using the 1981-2014 hindcasts of the Predictive Ocean Atmosphere Model for Australia version 2 (POAMA-2) subseasonal-to-seasonal prediction system. Generally, the good prediction skills of SEHD frequency appear in the southern AMR south of 308N including the Indian subcontinent, Indo-China peninsula, and the Philippines; the anomaly correlation coefficients between the observed and predicted region-mean SEHD anomalies are 0.72, 0.72, 0.70, 0.60, 0.61, and 0.61 at 1-6 months lead, respectively, all statistically significant at the 99.9% confidence level. The high prediction skills in POAMA-2 are due to its capacity on reproducing the observed delayed ENSO impacts on the large-scale atmospheric circulation, the seasonal surface air temperature, and thus the SEHD frequency in the southern AMR via provoking the Indo--western Pacific Ocean capacitor effect. Since POAMA-2 only provides the prediction at most half a year in advance, we also conduct the hindcasts in the SINTEX-F that can reproduce well the robust ENSO--SEHD relationship and has high prediction skill of ENSO itself. Results show that skillful prediction of the region-mean SEHD frequency can be up to 14 months in advance. These results are complementary to Part I of this study that ENSO can impact the SEHDs in the AMR and provide the sources of predictability. [ABSTRACT FROM AUTHOR]

From mid‐May to late June, the eastward propagation of some mid‐tropospheric cyclones (MTCs) originating in the Bay of Bengal (BOB)‐Burma (BUM) region across northern Indochina and southwest China to East Asia are observed. From 1979 to 2016, 137 MTCs were identified for the BOB‐BUM region. Eighty‐eight MTCs were trapped over northern Indochina, but 49 were propagated by the southwesterly flow of the BOB mid‐tropospheric trough to reach East Asia. Thirty‐one moved across Taiwan, but 18 did not. Eventually, all these MTCs moved to Okinawa. The former group of rainstorms produced rainfall ≥100 mm·day−1 over Taiwan, while 44 rainstorms generated rainfall ≥50 mm·day−1 over Okinawa. The 49 eastward propagating through‐Indochina MTCs exhibited the following salient features: (a) initial formation mostly occurred in the mid‐troposphere ahead/within the BOB trough in the morning over the BOB, but in the afternoon‐evening over BUM. (b) The eastward propagating BOB‐BUM MTCs underwent two descending processes: descending one mandatory level 6 hr after formation, and descending again from 700 to 925 hPa over southeastern China to interact with a low‐level cyclonic shear flow. (c) Intensified (weakened) by dipole anomalous circulation cells, the confluent monsoon southwesterly flow west (east) of Taiwan facilitated the merger of the MTC with a local front. (d) Rainfall produced by rainstorms over Taiwan/Okinawa was maintained by the intensified convergence of water vapour flux toward Taiwan/Okinawa. This hydrological process was stronger toward Taiwan than Okinawa and generated more rainfall in the former region. The impact of the BOB‐BUM MTC on East Asian weather is confirmed by this study. [ABSTRACT FROM AUTHOR]

[Display omitted] • Triassic medium-grade metamorphism is recognized in Hainan Island, the eastern Paleo-Tethyan tectonic domain. • Amphibolite-facies metamorphism of the Mulantou Metamorphic Complex took place at ca. 250–235 Ma. • Peak metamorphic conditions reached 717–771 °C and 4.4–5.8 kbar, equivalent to a geothermal gradient of approximately 30 °C/km. • Mulantou Triassic amphibolite facies metamorphism resulted from collision between the South China and Indochina blocks after closure of the Paleo-Tethys. The Permian-Triassic tectonic evolution of Southeast Asia has long been a subject of considerable debate. Hainan Island in China is located at the junction of the South China and Indochina blocks adjacent to the Pacific (Philippine) Plate. Studies of metamorphic complexes in Hainan Island may shed lights on the Permian-Triassic tectono-thermal events of the eastern Paleo-Tethys. Among these complexes, the newly recognized Mulantou Metamorphic Complex is sporadically exposed in northeastern Hainan Island provides evidence for above-mentioned issues. In this paper, we present the result of a combined petrological and geochronological study of paragneisses in this complex. The paragneisses consist mainly of biotite, plagioclase, quartz, and rutile/ilmenite, with or without garnet, sillimanite, and muscovite. Textural relationships, mineral compositions, and thermobarometric calculations show that these paragneisses record peak metamorphic P − T conditions of 720–770 ℃ and 4.4–5.8 kbar. Zircon and monazite U − Pb dating by laser ablation–inductively coupled plasma–mass spectrometry indicates that metamorphism occurred at 250–235 Ma. Integrating published geochronological, geochemical, and structural data of Hainan Island and along the Jinshajiang − Ailaoshan − Song Ma suture zone, we infer that the Triassic amphibolite-facies metamorphism of the Mulantou Metamorphic Complex resulted from collision between the South China and Indochina blocks after closure of the Paleo-Tethys. [ABSTRACT FROM AUTHOR]

The Indochina biomass burning (BB) season in springtime has a substantial environmental impact on the surrounding areas in Asia. In this study, we evaluated the environmental impact of a major long-range BB transport event on 19 March 2018 (a flight of the High Altitude and Long Range Research Aircraft (HALO; https://www.halo-spp.de , last access: 14 February 2023) research aircraft, flight F0319) preceded by a minor event on 17 March 2018 (flight F0317). Aircraft data obtained during the campaign in Asia of the Effect of Megacities on the transport and transformation of pollutants on the Regional to Global scales (EMeRGe) were available between 12 March and 7 April 2018. In F0319, results of 1 min mean carbon monoxide (CO), ozone (O 3) , acetone (ACE), acetonitrile (ACN), organic aerosol (OA), and black carbon aerosol (BC) concentrations were up to 312.0, 79.0, 3.0, and 0.6 ppb and 6.4 and 2.5 µ g m -3 , respectively, during the flight, which passed through the BB plume transport layer (BPTL) between the elevation of 2000–4000 m over the East China Sea (ECS). During F0319, the CO, O 3 , ACE, ACN, OA, and BC maximum of the 1 min average concentrations were higher in the BPTL by 109.0, 8.0, 1.0, and 0.3 ppb and 3.0 and 1.3 µ g m -3 compared to flight F0317, respectively. Sulfate aerosol, rather than OA, showed the highest concentration at low altitudes (<1000 m) in both flights F0317 and F0319 resulting from the continental outflow in the ECS. The transport of BB aerosols from Indochina and its impacts on the downstream area were evaluated using a Weather Research Forecasting with Chemistry (WRF-Chem) model. The modeling results tended to overestimate the concentration of the species, with examples being CO (64 ppb), OA (0.3 µ g m -3) , BC (0.2 µ g m -3) , and O 3 (12.5 ppb) in the BPTL. Over the ECS, the simulated BB contribution demonstrated an increasing trend from the lowest values on 17 March 2018 to the highest values on 18 and 19 March 2018 for CO, fine particulate matter (PM 2.5) , OA, BC, hydroxyl radicals (OH), nitrogen oxides (NO x) , total reactive nitrogen (NO y) , and O 3 ; by contrast, the variation of J(O1D) decreased as the BB plume's contribution increased over the ECS. In the lower boundary layer (<1000 m), the BB plume's contribution to most species in the remote downstream areas was <20 %. However, at the BPTL, the contribution of the long-range transported BB plume was as high as 30 %–80 % for most of the species (NO y , NO x , PM 2.5 , BC, OH, O 3 , and CO) over southern China (SC), Taiwan, and the ECS. BB aerosols were identified as a potential source of cloud condensation nuclei, and the simulation results indicated that the transported BB plume had an effect on cloud water formation over SC and the ECS on 19 March 2018. The combination of BB aerosol enhancement with cloud water resulted in a reduction of incoming shortwave radiation at the surface in SC and the ECS by 5 %–7 % and 2 %–4 %, respectively, which potentially has significant regional climate implications. [ABSTRACT FROM AUTHOR]

In Southeast Asia, Cambodia is one of the least studied countries in terms of liverwort diversity. A partial study of about 500 specimens gathered from 2009 to 2013 yielded 66 species new to the country, which raised the number of known species in Cambodia to 210, a number still far below expectations. Twenty genera are new to the country, including Dumortiera, Jackiella, and Lepidozia that are very common and characteristic elements of the mesophytic tropical flora in Asia. The distribution within the country of already known species is supplemented with new data. Two new combinations are proposed: Plectocolea polyrhizoides (Grolle) Bakalin et S.S. Choi comb. nov. and Plectocolea longifolia (Schiffn.) Bakalin et S.S. Choi comb. nov. [ABSTRACT FROM AUTHOR]

The mitogenome of an endemic catfish Clarias camerunensis was determined from the Cameroon water. This circular mitogenome was 16,511 bp in length and comprised 13 protein-coding genes, 2 ribosomal RNAs, 22 transfer RNAs, and a single AT-rich control region. The heavy strand accommodates 28 genes, whereas the light strand is constituted by ND6 and eight transfer RNA (tRNA) genes. The C. camerunensis mitochondrial genome is AT biased (56.89%), as showcased in other Clarias species. The comparative analyses revealed that most of the Clarias species have 6 overlapping and 11 intergenic spacer regions. Most of the PCGs were initiated and terminated with the ATG start codon and TAA stop codon, respectively. The tRNAs of C. camerunensis folded into the distinctive cloverleaf secondary structure, except trnS1. The placement of the conserved domains in the control region was similar in all the Clarias species with highly variable nucleotides in CSB-I. Both maximum likelihood and Bayesian-based matrilineal phylogenies distinctly separated all Clarias species into five clades on the basis of their known distributions (South China, Sundaland, Indochina, India, and Africa). The TimeTree analysis revealed that the two major clades (Indo-Africa and Asia) of Clarias species might have diverged during the Paleogene (≈28.66 MYA). Our findings revealed the separation of Indian species (C. dussumieri) and African species (C. camerunensis and Clarias gariepinus) took place during the Paleogene, as well as the South Chinese species (Clarias fuscus) and Sundaland species (Clarias batrachus) splits from the Indochinese species (Clarias macrocephalus) during the Neogene through independent colonization. This pattern of biotic relationships highlights the influence of topography and geological events in determining the evolutionary history of Clarias species. The enrichment of mitogenomic data and multiple nuclear loci from their native range or type locality will confirm the true diversification of Clarias species in African and Asian countries. [ABSTRACT FROM AUTHOR]

The snorkel snail genus Rhiostoma Benson, 1860 is comprised of terrestrial cyclophorid snails with wideranging species diversity and radiation in Southeast Asia. The typical characters of the genus are a depressed shell, a detached and descending portion of the last whorl with a distinctive peristomal breathing device attached, and a calcareous cup-shaped operculum. Herein, we have revised the systematics of extant species based on shell morphology combined with COI barcoding. From these thirty recognised species, twelve are described as new to science: R. ? amarapuraense sp. nov., R. anceyi sp. nov., R. breviocollar sp. nov., R. ebenozostera sp. nov., R. cheliopegma sp. nov., R. furfurosum sp. nov., R. gnomus, sp. nov., R. lannaense sp. nov., R. laoense sp. nov., R. platymorpha sp. nov., R. rhothonotaphrosa sp. nov., and R. tigrina sp. nov. All conchological characters are provided via illustrations of type specimens and living snails, and descriptions of the shells and radulae. Phylogenetic analysis based on partial COI gene sequences strongly supports the designated morphospecies and a monophyletic Rhiostoma, confirming that all pterocyclinid snails with a calcareous, cup-shaped operculum belong to the same clade. A high intra-specific divergence was observed in R. jalorensis and R. housei populations from locations in close proximity, suggesting a lower dispersal and higher level of isolation. The low inter-specific divergence found in R. hainesi, R. samuiense, R. asiphon, and R. rhothonotaphrosa sp. nov. supports their recent diversification and local adaptation, and is congruent with their marked morphological differences. Finally, nine formerly Rhiostoma-placed species were reclassified into either the genus Cyclotus or the genus Opisthoporus. [ABSTRACT FROM AUTHOR]

Raphiocarpus taygiangensis, a new species of Gesneriaceae family discovered in Tay Giang District, Quang Nam Province, Central Vietnam, is here described and illustrated. The new species is diagnosed by the combination of its stem up to 2 m long, sericeous hairs on young stem, leaf petiole and adaxial mid-vein, sparsely and minutely serrate leaf margin, axillary inflorescence spreading along stem, sparsely long glandtipped hairs on peduncle, pedicel, calyx, outside corolla and pistil, calyx 5-disparted from base, purplish white flower with purple stripes inside corolla tube, and dish-shaped stigma formed by 2 semi-orbicular lobes horizontally expanding. Distinct features of the new species and its morphologically closest congener, Rhaphiocarpus axillaris, are compared and discussed. The conservation status of the described species is estimated as Vulnerable (VU D2) according to the IUCN Red List Criteria. [ABSTRACT FROM AUTHOR]

The tribe Acanthoplectrini (Myrmeleontidae: Dendroleontinae) includes a group of antlion genera widely distributed across the Australasian and Oriental regions. The intergeneric and interspecific relationships between or within the Australian and Oriental lineages of this tribe as well as their historical biogeography remain largely unexplored. Here, we present a molecular phylogenetic and biogeographic analyses of Acanthoplectrini to infer the diversification history of this tribe, with emphasis on the Oriental lineage. Both the Oriental and Australian lineages are monophyletic and recovered as sister groups. Ancestral area reconstruction suggests that the ancestor of Acanthoplectrini might have been once widely distributed from Indochina to Australia and then split into the Oriental and Australian lineages during the early-Miocene. Our analyses recovered northeastern Indochina and south China as the ancestral range of the Oriental Acanthoplectrini. During the mid-Miocene to the mid-Pliocene, orographic events such as the rising of mountain ranges (including the Himalayas) and the formation of major islands in southeastern Asia triggered several dispersal and vicariance events in the Oriental Acanthoplectrini, driving their speciation. We revise the classification of the Oriental Acanthoplectrini, establishing the new genus Paralayahima gen. n., which is recovered sister to Layahima Navás. Moreover, we describe four new species of Layahima, Layahima aspoeckorum sp. n., Layahima monba sp. n., Layahima lhoba sp. n. and Layahima xinliae sp. n., and we reinstate two previously synonymized species, Layahima melanocoris (Yang) stat. rev. and comb. n. and Layahima nebulosa Navás stat. rev. [ABSTRACT FROM AUTHOR]

This article describes the results of a three-year study of invasive species of aquatic ecosystems in the vicinity of Ust-Luga, the largest Russian seaport in the Baltic. Taking into account the great importance of the participation of marine vessels in the dispersal of invasive species, an experimental study of the seasonality of accumulation of resting stages of aquatic invertebrates in the ballast compartments of a vessel located in the Baltic Sea of the Gulf of Finland was carried out. Experiments show that the time of filling the ballast compartments in late summer and autumn poses the greatest risk for the spread of aquatic invertebrates with ship ballast water. In the Baltic Russian port, 11 invasive species of zooplankton and zoobenthos were found, which comprises 15% of the biodiversity in the samples. Copepoda demonstrated the highest presence of invasive species in class among zooplankton groups (14%) and Malacostraca among benthos groups (80%). Alien species findings correspond to the main vectors of invasive species dispersal for the Baltic Sea: North America, Indochina, and the Ponto-Caspian region. [ABSTRACT FROM AUTHOR]

The Indochinese Peninsula is a main center of speciation of Capparis, but the taxonomic treatment of the genus is still critical in this area. With regard to Vietnam, a discordant number of species was recorded by different authors during the last century, whereas various new species have been recently described. An updated checklist of the intrageneric taxa occurring in the country is here presented, including a new species from the island of Hon Tre, Khanh Hoa Province. The genus comprises in Vietnam 37 species, 9 subspecies and 3 varieties, all belonging to Capparis sect. Monostichocalyx. The study area, with 10 endemic species, is confirmed as one of the hotspots of the genus. Three lectotypes are also selected. The new species here described and illustrated, C. oxycarpa, is related to C. pranensis, differing in the few-flowered subumbels, narrower sepals, smaller petals, longer filaments and smaller, apiculate fruit; its affinities with related taxa and conservation status are discussed, and data on its ecology and phenology are given. [ABSTRACT FROM AUTHOR]

The eastern Paleo-Tethyan Jinshajiang–Ailaoshan–Song Ma orogenic belt in the Southeast Tibetan Plateau represents the tectonic boundary between the Indochina and South China blocks. Regional Cenozoic lithospheric strike-slip movements caused by the India–Asia collision have modified many of the pristine geological records associated with the Indosinian orogeny. The lack of reliable petrological evidences, particularly of high-pressure (HP) metamorphism, has hindered the tracing of the evolutionary history of the Paleo-Tethyan orogenic belt. We report the mineralogy, geochemistry, geochronology and thermodynamic modelling of eclogite lenses/blocks and their host garnet–phengite schists from the Song Ma Suture Zone of Northwest Vietnam and reveal their protolith origins and metamorphic evolution. The eclogites are geochemically similar to mid-ocean ridge basalt, showing weak depletions in high field-strength elements, positive to slightly negative whole-rock ɛNd(t) ratios (−1.69 to +5.15) and slightly high 87Sr/86Sr(t) ratios (0.70466–0.70834). The igneous protolith of the eclogites formed in the late Silurian (425.4 ± 3.6 Ma; igneous zircon dating, 638–459 Ma TDM dating), which makes them the oldest known mid-ocean ridge mafic rocks in an ancient Paleo-Tethyan Ocean. Various eclogites preserve similar peak mineral assemblages (garnet + omphacite + phengite + rutile + quartz ± epidote/clinozoisite ± kyanite ± winchite) under indistinguishable peak conditions. Their prograde P–T trajectories show a uniform pattern of progressive heating and weak compression along a geothermal gradient of 8°C–10°C/km, indicating a warm subduction setting at a low angle that contrasts with the cold oceanic subduction recorded in the adjacent Paleo-Tethyan suture zones. Combined with detrital U–Pb ages from previous studies, our geochronological data indicate that the host schists originated from continental crust within the South China Block and underwent a pervasive Triassic HP metamorphism related to the Indosinian orogeny. The eclogites and host schists yielded HP metamorphic ages of 239–234 Ma and retrogressive amphibolite-facies metamorphic ages of 231–229 Ma, suggesting rapid cooling (14.0°C–21.6°C/Myr) and exhumation (6.4 km/Myr) from the mantle to the crust. The Song Ma eclogites and their host schists formed when the final ocean closure transitioned to the initial Indochina–South China collision. The Song Ma eclogites and their host schists provide essential information on the opening and closure of the eastern Paleo-Tethys and the subsequent amalgamation of Southeast Asian continental fragments. [ABSTRACT FROM AUTHOR]

The body of knowledge regarding the classification and evolution of freshwater mussels in the family Unionidae (Bivalvia) in Indochina has recently increased. However, the taxonomic revision of all extant taxa in the region is still ongoing. In this study, the genus Pilsbryoconcha was revised based on an integrative analysis of shell morphology, biogeography, and molecular data. Multi-locus phylogeny indicated the availability of eight species within the genus. Four previously recognized species are P. exilis (Lea, 1838), P. schomburgki (Martens, 1860) stat. rev., P. linguaeformis (Morelet, 1875), and P. carinifera (Conrad, 1837), while four other species are described herein as P. acuta sp. nov., P. mekongiana sp. nov., P. kittitati sp. nov., and P. hoikaab sp. nov. In addition, the neotype of P. carinifera is also designated to clarify its long taxonomic ambiguity. Divergent time estimation and historical biogeography analysis revealed that Pilsbryoconcha originated in the area now called the Khorat Plateau around the middle of the Eocene (mean age = 43.12 Mya), before its range was expanded across Indochina through a series of complex geomorphological changes of river systems, which also led to diversification of the genus. [ABSTRACT FROM AUTHOR]

Land use/cover (LUC) datasets are the basis of global change studies and cross-scale land planning. Data fusion is an important direction for correcting errors and improving the reliability of multisource LUC datasets. In this study, a new fusion method based on Bayesian fuzzy probability prediction was developed, and a case study was conducted in five countries of the Indochina Peninsula to form a fusion dataset with a resolution of 30 m in 2020 (BeyFusLUC30). After precision and uncertainty analysis, it was found that: (1) using accuracy validation information as prior knowledge and considering spatial relations can be well applied to LUC data fusion. (2) When compared to the four source datasets (LSV10, GLC_FCS30, ESRI10, and Globeland30), the accuracy indices of BeyFusLUC30 are all optimal. The average overall consistency increased by 6.42–13.61%, the overall accuracy increased by 4.84–7.11%, and the kappa coefficient increased by 4.98–7.60%. (3) The accuracy of the fusion result improved less for land types with good original accuracy (cropland, forest, water area, and built-up land), and the improved range of F1 score was at least 0.40–2.29%, and at most 6.66–9.88%. For the land types with poor original accuracy (grassland, shrubland, wetland, and bare land), the accuracy of the fusion result improved more, and the F1 score improved by at least 4.02–5.82%, and at most 14.41–48.35%. The LUC dataset fusion and quality improvement method developed in this study can be applied to other regions of the world as well. BeyFusLUC30 can provide reliable LUC data for scientific research and government applications in the peninsula. [ABSTRACT FROM AUTHOR]

Felsic dykes from the Dalat zone (southern Vietnam) are commonly NE–SW oriented and penetrate early cretaceous volcanic-plutonic rocks. These felsic dykes consist of predominant porphyritic granite, minor granitic aplite and aplite. The primary rock-forming minerals are plagioclase, K-feldspar, quartz and subordinate biotite, and the main secondary mineral is epidote. Geochemically, these felsic dykes are characterized by I-type affinity and high SiO2 content (>71 Wt%), low to moderate Al2O3, and variable total alkali (Na2O+K2O). Trace and rare-earth elements show the enrichment of LILEs such as Rb, U, Th, and K and the depletion of HFSEs such as Nb and Ti and a strongly negative Eu anomaly, indicating fractional crystallization of K-feldspar, plagioclase and titanite. Zircons obtained from the felsic dykes are prismatic and exhibit oscillatory zoning with Th/U ratio > 0.1 typical for magmatic origin. In situ zircon LA-ICP-MS zircon U-Pb dating yielded a weighted mean 206Pb/238U age of 91 Ma, temporally coeval with Early Cretaceous magmatism, which has been widely reported to originate from Paleo-Pacific subduction. Their (87Sr/86Sr)i ratio (0.709917 to 0.715288), whole-rock εNd(t) values (−1.3 to +0.9), zircon εHf(t) values (+3.1 to +9.5), and whole-rock Nd and zircon Hf model ages (TDM2) (999–552 Ma) of the studied felsic dykes indicate that they might derive from partial melting of neoproterozoic crustal materials with a input of mantle-derived melt during magma formation and differentiation. The obtained geochemical and isotopic characteristics suggest that these felsic dykes are genetically related to I-type granite and might have formed during the late stage of the Late Mesozoic Paleo-Pacific subduction beneath Indochina or shortly prior to the subsequent extensional regime due to slab retreat. [ABSTRACT FROM AUTHOR]

Here we describe a new subgenus and three new species of parasitic water mites in the genus Unionicola (Acari: Hydrachnidia) from Myanmar: Myanmaratax subgen. nov., Unionicola (Myanmaratax) savadiensis subgen. and sp. nov. (hosts: Lamellidens savadiensis and L. generosus), U. (My.) generosa sp. nov. (the same hosts), and U. (My.) trapezidenssp. nov. (hosts: Trapezidens dolichorhynchus and T. angustior). These taxa were identified based on a two-gene phylogenetic analysis (COI + 28S), which also confirms the division of the genus Unionicola into numerous subgenera. The new species are cryptic species, which are morphologically indistinguishable but strongly resemble U. (Prasadatax) brandti Vidrine, 1985 described from Thailand (hosts: Lens spp. and Ensidens spp.). We also transfer the latter taxon from Prasadatax to Myanmaratax based on a set of morphological evidence and propose U. (My.) brandti comb. nov. The new subgenus contains a total of five species, one of which needs future sampling efforts and will be described elsewhere. Additionally, 56 valid subgenera, which were placed in the synonymy of the genus and in one case raised to the genus level, are restored here until robust phylogenetic evidence on their taxonomic status is available. Our results also confirm that Unionicola mites are narrow host specialists that are associated with either one or a few closely related freshwater mussel species belonging to one or two sister genera. [ABSTRACT FROM AUTHOR]