Annamite Research Articles

The genus Dedalopterus Sabatinelli & Pontuale, 1998 (Scarabaeidae: Melolonthinae: Leucopholini) in Laos and Vietnam, with description of a new species.

The genus Dedalopterus Sabatinelli & Pontuale, 1998 from Laos and Vietnam is reviewed: three species are present of which Dedalopterus lexuanhuei Pham, Ahrens & Sabatinelli, new species from Central Vietnam (Ngoc Linh Mts., Annamite Range) is here described. Dedalopterusmalyszi Bunalski, 2001 is present in North Vietnam (Lao Cai, Hoang Lien Son Range), and Dedalopterus pulchellus Sabatinelli & Pontuale, 1998 (= D.bezdekorum Zdek & Krajk, 2007, new synonymy) is known from Northeast Laos (Mt. Xiangkhouang and Mt. Phou Pan). Additional records, an updated checklist, and an identification key of the genus Dedalopterus are provided. All species treated are abundantly illustrated.

Tadpole of the Vietnamese jelly-nest tree frog, Feihyla palpebralis (Anura: Rhacophoridae): external morphology and chondrocranium.

The genus Feihyla Frost, Grant, Faivovich, Bain, Haas, Haddad, de S, Channing, Wilkinson, Donnellan, Raxworthy, Campbell, Blotto, Moler, Drewes, Nussbaum, Lynch, Green & Wheeler was established relatively recently (Frost et al. 2006), but to date its composition has changed several times due to the extremely confusing and labile systematics of small rhacophorids (e.g., Grosjean et al. 2008; Hertwig et al. 2013; Biju et al. 2020). It embeds rather miniature, delicate tree frogs and currently comprises six species (Frost 2023). The type species, Feihyla palpebralis (Smith 1924), was described from Mount Langbian in the southern part of the Truong Son Range (Annamite Mountains) and was long considered endemic to Vietnam; recent reports that it is also distributed in China can be based on misidentification and need reliable confirmation (Biju et al. 2020).

Truongsonia (Arecaceae: Arecoideae: Truongsonieae)—a new palm genus and tribe from Vietnam

A genus and species of palm from the Truong Son Range in Vietnam, Truongsonia lecongkietii, is described as new to science. Phylogenomic analysis strongly supports the placement of the new taxon in subfamily Arecoideae as sister to the African endemic tribe Podococceae, which comprises a single genus Podococcus. A new tribe Truongsonieae is also described to accommodate Truongsonia in the current phylogenetic classification of palms. Truongsonia is a dwarf, acaulescent, clump-forming palm bearing entire, bifid leaves with a fibre-like extension of the rachis through the sinus of the two lobes of the leaf. The interfoliar inflorescence is exserted on a long peduncle with 3­–4 tightly sheathing peduncular bracts and rachillae presented at the apex only. The ovary is triovulate-tricarpellate, but fruits are single-seeded. Truongsonia is Critically Endangered, with surveys locating only 10–15 plants in the wild. Swift conservation action is required to secure the future of this remarkable and phylogenetically isolated lineage of palms.

Rising temperatures over the Greater Mekong Subregion in CMIP6: Present-day biases and constraint future projections

This study evaluates the historical simulation of surface air temperature (SAT) over the Greater Mekong Subregion (GMS) during the period 1981–2014 with 31 models from Coupled Model Intercomparison Project phase 6 (CMIP6). The CMIP6 multi-model ensemble shows a weaker SAT growth trend than the reanalysis data in all seasons. The SAT increase is underestimated mostly in winter, by around 0.2 °C/decade. The simulated SAT climatology shows positive bias over the Gaoligong Mountain in western Yunnan, the Rakhine Mountain in Myanmar, and the Annamite Range in southern Vietnam, and negative bias elsewhere. We make a best-model ensemble to improve the representability of the GMS SAT. The range of SAT interannual variability is underestimated over most parts of GMS in boreal spring, autumn, and winter. In summer, the SAT range bias shows a dipole pattern with negative bias over the northwestern GMS and positive bias over the southeastern GMS. Dynamical diagnosis suggests that the bias in vertical velocity perturbation, manifesting as weakened regional Hadley circulation, is a major contributor to the SAT range bias in summer via vertical advection of mean potential temperature. The bias-corrected projection of the summer SAT is presented for three shared socio-economic pathways (SSPs). The SAT rising relative to the reference period 1995–2014 tends to be more spatially homogeneous under higher emission scenarios. The range of SAT interannual variability would increase over the northern GMS but decrease over the southern GMS under three SSPs scenarios. This SAT dipole variation is associated with intensified regional Hadley circulation over the GMS. The results also reiterate the urgent need for net zero emission by 2050 to maintain a sustainable environment.

Investigation of an extreme rainfall event during 8–12 December 2018 over central Vietnam – Part 1: Analysis and cloud-resolving simulation

Abstract. An extreme rainfall event occurred from 8 to 12 December 2018 along the coast of central Vietnam. The observed maximum rainfall amount in 72 h was over 900 mm and set a new record, and the associated heavy losses were also significant. The analysis of this event shows some key factors for its occurrence: (1) the interaction between the strong northeasterly winds, blowing from the Yellow Sea into the northern South China Sea (SCS), and easterly winds over the SCS in the lower troposphere (below 700 hPa). This interaction created strong low-level convergence, as the winds continued to blow into central Vietnam against the Truong Son Range, resulting in forced uplift over the coastal plains due to the terrain's barrier effect. Furthermore, the low-level convergence in this event was strong enough, and the air was unstable enough to trigger most of the convection near the shoreline (further inland). As a consequence, heavy rainfall occurred along the coastal zone and coastal sea. (2) The strong easterly wind played an important role in transporting moisture from the western North Pacific (WNP) across the Philippines and the SCS into central Vietnam. (3) The Truong Son Range also contributed to this event due to its barrier effect. (4) In addition to cumulonimbus, the low-level precipitating clouds such as nimbostratus clouds were also major contributors to rainfall accumulation for the whole event. The analyses of local thermodynamics also indicate that the southward movement of the low-level wind convergence zone caused the southward movement of the main heavy rain band during the event. The cloud-resolving storm simulator (CReSS) was employed to simulate this record-breaking event at a grid size of 2.5 km; evaluated results show that the model simulated the surface wind well and captured the southward movement of the low-level wind convergence. The overall rainfall can be captured quite well, not only in quantity but also in its spatial distribution (with a similarity skill score (SSS) ≈0.7 and threat score (TS) >0 at 700 mm for 72 h rainfall). Thus, the CReSS model is shown to be a useful tool for both research and forecasts of heavy rainfall in Vietnam. The model performed better for the rainfall during 9–10 December 2018 but not as good on 11 December 2018. In the sensitivity test without the terrain, the model had poorly simulated the surface wind, which resulted in the model generating insufficient rainfall for this event and also not capturing the spatial distribution of the rainfall. Thus, the test confirms the important role played by the local topography for the occurrence of this event.

Diurnal Variation of Summer Monsoon Season Precipitation Over Southern Hainan Island, China: The Role of Boundary Layer Inertial Oscillations Over Indochina Peninsula

AbstractIn June after the onset of the East Asian summer monsoon season, rainfall on the south side of Hainan Island (HNI) of China exhibits a trimodal pattern with an unusual peak near noon. A typical case of 20 June 2017 is chosen to analyze the mechanisms through a convection‐permitting simulation together with rainfall observations. Clockwise rotation in low‐level winds is found at and off the coast of south HNI, leading to maximum onshore southwesterly winds in the late morning that is closely linked to the diurnal variation of rainfall. The offshore diurnal variations of low‐level winds are tracked upstream and attributed to boundary layer inertial oscillations over the inland plain of Indochina Peninsula. In addition, a short wide gap comprised mostly of hills lower than 700 m is located across the higher Annamite Range along the east coast of the Peninsula, right upstream of HNI. Nocturnal boundary layer low‐level jet (LLJ) forming over the plain passes through the gap with significant acceleration due to gap channeling and downslope flow effects, reaching peak intensity off the Peninsula coast at around 09 local standard time (LST). The enhanced LLJ propagates downstream towards HNI and impinges on the mountains at around 12 LST when rainfall reaches peak there. As the inertial‐oscillation‐indued perturbation winds approaching the Island weaken and eventually reverse direction, lifting weakens and low‐level stability increases as descending motion develops offshore. Rainfall on the southern Island therefore dissipates in late afternoon.

A new species of Xenophrys (Amphibia: Anura: Megophryidae) from Truong Son Range, Vietnam.

A new species of Xenophrys is described from Truong Son Range in Central Vietnam based on morphological and molecular differences. The new species is distinguishable from its congeners by a combination of the following characters: Size medium (SVL 58.871.4 mm in males, 65.687.3 mm in females); tympanum distinct; vomerine teeth present; tongue notched posteriorly; external vocal sac absent; toes with rudimentary webbing; subarticular tubercles absent, lateral fringes narrow along toes; nuptial pads absent in males; dorsal skin of body with weak granules; flank with small tubercles; dorsum with a dorsal ridge in >-< shape; dorsolateral folds prominent; dorsal surface from reddish brown to grayish brown with a brown triangle between the eyes, and a dark brown marking edged along dorsal ridge on the back; and small white spots present on flank and back of thigh. In the phylogenetic analyses, the new species is nested within the genus Xenophrys with interspecific uncorrected genetic p-distances (16S rRNA gene) from 2.22.8% (compared with Xenophrys maosonensis) to 14.414.7% (compared with Xenophrys yeae).

Trees Are Gods: The Sanctification of Forests in the Traditional Worldview of the Co Tu People in Vietnam

Purpose. Co Tu is one of the ethnic minorities among the 54 ethnic groups in Vietnam that still boldly preserve their cultural values. They live in the mountainous areas of the Annamite Range, Vietnam where they depend on the forest for their livelihood. The people attach great importance to trees and forests. In their traditional worldview, trees are not merely immovable objects but have hidden souls. Trees are called abhui whose souls mainly inhabit the forest. Those residing in any tree have the same characteristics as that tree. Tree souls can protect people but can also harm them. By using primary and secondary documents obtained during the years 2009–2020, focusing on 2017–2019; emic, etic, and direct field trip methods as the unstructured in-depth interview, semi-structured interview, and group discussions, we want to approach the ethnic minority’s way of thinking and learn about the relationship between the ethnic group and the plant world.Results. Trees have been personified as gods, and from that respect, the people have also sanctified forests and created customary law to protect forests, i.e., tree souls, the sacredness of forests.Conclusion. In promoting relationships with nature, protecting and preserving the environment, these indigenous practices are a very positive form that should be encouraged.

Rapid decline and fragmentation of the distribution of an enigmatic small carnivore, the Owston’s Civet, in response to future climate change

Indochina is known as one of the world’s biodiversity hotspots, with populations of many endangered and/or endemic species dramatically declining due to a range of threats, such as illegal hunting, habitat destruction, and global climate change. Climate change is expected to alter the region’s habitat and ecosystem conditions, force contraction of species ranges, and increase the likelihood of local extinctions. Maxent is a widely used modelling approach to predict the species’ current potential distribution, project range shifts in response to climate change, and inform conservation planning. Here, we collated known records and built models for both present and future climatically suitable habitat of the Owston’s Civet (Chrotogale owstoni), an endangered and poorly studied small carnivore occurring in Vietnam, eastern Laos, and a small part of southern China. Projections of climatically suitable habitat for the civet in most climate change scenarios and timeframes suggest significant habitat loss and fragmentation within its current range as a consequence of upward contraction. We recommend that future conservation efforts for C. owstoni focus on key refugia spreading along the Annamite Range in the border area between Vietnam and Laos. To mitigate climate-related extinction risk, close cooperation between Vietnam and Laos’ governmental agencies, research institutions, and non-governmental conservation organizations will play an important role in conserving the remaining habitat of this endangered species.

Two new cryptic species of Microhyla Tschudi, 1838 (Amphibia, Anura, Microhylidae) related to the M. heymonsi group from central Vietnam.

The Microhyla heymonsi species complex from central Vietnam was examined, and based upon morphological and molecular evidence, two new species are described. The discovery of Microhyla daklakensissp. nov. and Microhyla ninhthuanensissp. nov. brings the total number of known species in the genus to 46 and the species number of Microhyla in Vietnam to 13. The Truong Son Range harbors the highest diversity of the genus Microhyla with 11 recorded species so far. However, this apparent micro-endemic diversity is at risk because of habitat loss by deforestation, which highlights the necessity of further research leading to improved conservation measures.

Anatomical note on a tree snail Amphidromus (Amphidromus) cambojiensis (Reeve, 1860) from Vietnam (Eupulmonata: Camaenidae)

ABSTRACT A joint expedition between the Natural History Museum, London and Vietnamese colleagues discovered living populations of the charismatic tree snail, Amphidromus (Amphidromus) cambojiensis (Reeve, 1860), in a protected area of southern Vietnam. The genital morphology of this species is documented herein and could be used to re-assess its subgeneric position. The unique morphological characters of the purplish-pink colouration inside the aperture, a short penis (about half of the length of the vagina), twisted flagellum, and a long appendix, all suggest classifying this species into the nominotypical subgenus. Based on available specimens, this species appears to be endemic to the southern portion of the Annamite Range in southern Vietnam and probably Cambodia.

Rediscovery of Andrea's keelback, Hebius andreae (Ziegler & Le, 2006): First country record for Laos and phylogenetic placement

For more than a decade, the keelback snake Hebius andreae was only known from the holotype from the limestone forest in the central Truong Son (the Annamite Mountain Range) of Quang Binh Province in Vietnam. As the adult male was formaldehyde-fixed, the description was based on morphological characters only. During recent herpetological surveys in the karst forest of central Laos, opposite to the type locality of H. andreae on the other side of the Annamite Range, the Andrea's keelback is rediscovered. Based on a juvenile male from Bualapha District, Khammouane Province, within Hin Nam No National Protected Area, we herein report the first country record of this species from Laos, provide an expanded morphological definition, and for the first time recover the phylogenetic relationship of H. andreae, based on the sequences of four genes, including one mitochondrial, cytochrome b, and three nuclear markers, Cmos, NT3, and Rag1. The phylogenetic placement of H. andreae reveals it to be a member of Hebius, in fact the most basal representative of the genus. The rediscovery of the beautiful but still poorly known and obviously rare species underlines the conservation importance of the Annamite Mountain Range as habitat and refugium for the regional unique biodiversity, which only occurs in this karst massif.

Characteristics of Coastal Low‐Level Jets Over Beibu Gulf, China, During the Early Warm Season

AbstractWe investigated coastal low‐level jets (CLLJs) over Beibu Gulf, China, during the warm season (May to July) using hourly model simulations from a mesoscale weather research and forecasting model with a 9‐km horizontal resolution. Two high‐incidence CLLJ areas were identified over Beibu Gulf: one located on the leeward side of the Annamite Range that prevailed after sunset and the second off the northwestern coast of Hainan Island that reached its maximum intensity at midnight. The upstream wind of the Annamite Range was too weak to pass over the range during the daytime due to strong turbulent mixing near the land surface of Indochina; however, due to the suppression of the turbulent mixing after sunset, the flow intensified and crossed over the Annamite Range and further formed a hydraulic jump jet downstream. In addition to advection effect from upstream, topographic blocking effect of Hainan Island contributed to the CLLJ off the northwestern coast of Hainan Island, which persisted during the day but became more prevalent at midnight. Further momentum budget analysis and sensitivity experiments indicated that the upstream inertial oscillation due to the diurnal variation in turbulence over land was the primary source of the CLLJ over the ocean. These findings reveal the primary mechanism of CLLJs over Beibu Gulf, providing insight into CLLJ formation in other coastal regions with complex mountain ranges.

Diversity of medicinal plant species in Puxailaileng mountain area, Nghe An Province

Puxailaileng is an area with the most unique characteristics of biodiversity, with the highest peak in the Truong Son range of 2,711 m, so there are many unique factors here that other regions do not have. With an area of only nearly 50 thousand hectares, the research area has recorded 726 species of higher plants, of which 126 species belong to 28 genera in Nghe An. The endemism is also very high, due to the difference in terrain and climate, there are only 408/726 common species in Nam Can and Na Ngoi communes, 320 species are only found in one of two communes. In the Puxailaileng area, this study has recorded 588 medicinal plant species in 155 families in 5 divisions of vascular plants. Characteristics of diversity of habitat, stem type, collection and diversity of rare and precious species were also assessed, including 27 species listed in the Vietnam's Red Data Book (2007).

A new genus of praying mantis, Chlorocalis n. gen., with two new species from the Greater Mekong region (Mantodea: Mantidae)

SummaryA new genus of praying mantis is described, Chlorocalis n. gen., with two species, C. maternaschulzei n. sp. and C. prasina n. sp. from the Greater Mekong Region. Chlorocalis is placed in Mantidae and can be immediately recognized by the presence of dark brown (male) or yellow-whitish (female) oblique stripes on the forewings, a large conical bulge on the clypeus, two large conical bulges on either side of the inferior margin of the lower frons, and the male genitalia with two distal processes on the ventral phallomere. Chlorocalis maternaschulzei is a widespread lowland species with records as west as Nakhon Ratchasima Province, Thailand, and as east as mount Núi Chúa in southern Central Vietnam. We consider this species to be of Least Concern. In contrast, C. prasina is a narrow-range mountain endemic of the Vietnamese Central Highlands in the Annamite range and is assessed by us to be Vulnerable. The new findings demonstrate the still very poor knowledge on praying mantis species diversity in South-East Asia and the urgency to resolve this taxonomic deficiency in the face of biodiversity loss.

First record of Gracixalus quyeti (Amphibia: Anura: Rhacophoridae) from Laos: molecular consistency versus morphological divergence between populations on western and eastern side of the Annamite Range

First record of Gracixalus quyeti (Amphibia: Anura: Rhacophoridae) from Laos: molecular consistency versus morphological divergence between populations on western and eastern side of the Annamite Range

Evolution in karst massifs: Cryptic diversity among bent-toed geckos along the Truong Son Range with descriptions of three new species and one new country record from Laos.

Species designated as 'cryptic' share a similar morphotype, and are often only clearly separable by molecular data. Cyrtodactylus, the most diverse gecko genus of the family Gekkonidae, is a prime example, because many morphologically similar taxa have only recently been identified as new species as a result of available genetic evidence. However, while cryptic diversity of Cyrtodactylus is already well documented on the Vietnamese side of the Truong Son range, only scarce data is available from central Laos. In this study, we address this issue by means of an integrative approach, which employs morphological, molecular, and ecological data to distinguish cryptic species of the Cyrtodacylus phongnhakebangensis species group primarily distributed along the northern Truong Son Range. Our analyses based on 12 selected morphological characters, a partial mitochondrial gene (COI), and five ecological parameters revealed three undescribed cryptic Cyrtodactylus species from Hin Nam No National Protected Area, which are described as Cyrtodactylus calamei sp. nov., Cyrtodactylus hinnamnoensis sp. nov., and Cyrtodactylus sommerladi sp. nov. A fourth discovered Cyrtodactylus population in Hin Nam No proved to be the first country record of C. cryptus for Laos. Our results highlight the importance of applying an integrative approach to resolving the taxonomy of complex and cryptic species groups, and the role of the Truong Son Range in maintaining the high level of biodiversity over time.

Four new species of orchids (Orchidaceae) in eastern Vietnam

Dendrobium thinhii (D. sect. Breviflores), Sarcoglyphis tichii, Taeniophyllum phitamii (T. subgen. Codonosepalum Schltr.) and Trichoglottis canhii are described and illustrated as species new to science. All are local endemics of the area associated with Truong Son Range (Annamese Cordilleras) within territories of Dac Lak, Kon Tum and Lam Dong provinces of the southern Vietnam known in national geography as the Central Highlands or Tay Nguyen Plateau. All discovered plants are well-defined, taxonomically isolated species representing very strict plant endemism quite typical for the southern part of eastern Indochina.

The fishes of the Nam Theun and Xe Bangfai drainages, Laos

The fish diversity of the Nam Theun and Xe Bangfai drainages was surveyed between 1996 and 2012. 74 species are now recorded from the Nam Theun and 178 from the Xe Bangfai drainages. Twenty-one (28%) of the Nam Theun species are endemic and 9 (5%) of the Xe Bangfai species. At the time of the respective surveys, 54 species were new records for Laos, and 25 species were new to science. While the fish fauna of Xe Bangfai is similar to that of the other main tributaries of the Mekong in Laos, the fish fauna of the Nam Theun is characterised by a great proportion of endemics, several of which have affinities with species known from the opposite slope of the Annamite Range, in Vietnam. Besides, work conducted in relation with aquatic biodiversity surveys for the Nam Theun 2 project resulted in an increase of the fish fauna of Laos from 210 to 481 in 3 years between March 1996 and June 1999 and the discovery of 128 species new to science and lead to the publication of an identification guide. Specific studies have been conducted to assess the status of some of the endemic species that were potentially threatened by the Nam Theun 2 scheme: <i>Scaphognathops theunensis<i/> (still observed in 2012 downstream of Nakai Dam), <i>Tor ater<i/> (mainly restricted to streams upstream of the reservoir), and <i>Oryzias<i/> sp. 'swamp' (along the fringe of the reservoir). The status of the bitterling <i>Rhodeus laoensis<i/> and its associated mussel is still not clear. Most of the species endemic to the Nam Theun drainage are known upstream of the reservoir, which is a protected area. The endemic species known on Nakai Plateau and downstream of the dam are more at risk and require closer monitoring.

Study on Iron‐Copper‐Gold Mineralization in the Truong Son Metallogenic Belt, Laos‐Vietnam

The Truong son fold belt, located in the Truong son Range and in central Vietnam and eastern Laos, an elongate northwest trending belt,is dominated by a system of strikeslip faults, which forms part of the Indochina block. Rocks in the belt are metamorphosed up to the amphibolite facies grade, predominantly Early to Mid Paleozoic.The tectonic boundaries of the Truong son fold belt, Song Ma suture zone, Dien BienPhu Fault, Khorat Basin and Tamky-Phuoc Son fault lies to north, west and south of the belt respectively(Fig,1). The Truong son tectonic magmatic belt,the same position with fold belt, composed of volcanic rock and granite, which was formed in Caledonian, Variscan and Indosinian periods. Due to the particular geological background, the Truongson metallogenic belt has experienced complex diagenesis and mineralization, and rich mineral resources were formed. There are more than 70 gold, copper, iron, tin, lead and zinc deposits, including some large to super-large –scale deposits, such as Sepon copper-gold deposit, Phu Kham gold-copper deposit in Laos, and Thach Khe iron deposit in Vietnam.