Langbian Plateau Research Articles

Ground‐dwelling mammal and bird diversity in the southern Annamites: Exploring complex habitat associations and the ghost of past hunting pressure

AbstractThe Langbian Plateau, a biodiversity hotspot in the southern Annamites of Viet Nam, has undergone extensive hunting pressure. However, the limited information on the effects of overexploitation on the current status and community composition of wildlife hinders effective conservation efforts, including the implementation of targeted patrols to reduce snaring. In this study, we conducted a camera‐trapping survey across the Langbian Plateau, consisting of a broadleaf evergreen and coniferous habitat mosaic. We recorded 46 ground‐dwelling mammals and birds, including several threatened Annamite endemics. Using multi‐species Royle‐Nichols model and landscape covariates, we found higher richness in broadleaf evergreen forest located in more remote and less rugged areas. We then used species responses to covariates to predict species distribution and identify high‐priority areas for conservation. Furthermore, we constructed diversity profiles that indicated higher biodiversity in broadleaf evergreen forest compared to the coniferous forest. Finally, we used a dissimilarity index to assess the level of defaunation, revealing 16% of the community had been lost, with higher levels of defaunation for threatened and larger‐sized species. Our findings provide insights into the status, distribution, and occurrence of the ground‐dwelling mammal and bird communities in the Langbian Plateau, and can help stakeholders design more effective conservation strategies to protect existing populations.

A NEW CRYPTIC SPECIES OF THE GENUS Microhyla (AMPHIBIA: MICROHYLIDAE) FROM LANGBIAN PLATEAU, VIETNAM

An integrative taxonomic analysis combining molecular and morphological lines of evidence revealed a new cryptic species of the Microhyla achatina species group from the Langbian Plateau of southern Vietnam. The new species was previously confused with its recently described morphologically similar and sympatric sister species, M. pineticola. The new species can be distinguished from M. pineticola by the presence of a continuous dark stripe running from the posterior edge of its eye towards the groin (vs dark markings interrupted above the axilla), snout acuminate in lateral profile (vs rounded), belly colour pattern, and foot webbing. The new species is currently known only from Bidoup–Nui Ba National Park in Lam Dong Province, Langbian Plateau in southern Vietnam (at elevations of 1300–1600 m a.s.l). We suggest the new species to be considered as Near Threatened (NT) in the IUCN Red List. Our results emphasize that our understanding of the diversity of genus Microhyla is still far from complete, and provide further evidence for montane areas of southern Vietnam to be a centre of Microhyla species richness. Our study further underscores the urgent need for intensified integrative taxonomic research on Microhyla spp. in order to clarify the taxonomy of wide-ranging species complexes and to elaborate effective conservation measures.

A description of the tadpole of Megophrys "Brachytarsophrys" intermedia (Smith, 1921).

Megophrys Kuhl and Van Hasselt are an Asian radiation of terrestrial frogs which are usually associated with montane forest (Mahony et al. 2017). The Annam horned frog (Megophrys intermedia) is reported from montane evergreen forest in Vietnam and Lao People's Democratic Republic (Stuart 2005; Hendrix et al. 2008; Nguyen et al. 2009; Tran 2013; Orlov et al. 2015; IUCN 2017; Mahony et al. 2017). The IUCN Red List assessment for the species reports an elevational range of 782-1500 m asl (IUCN 2017) although the type locality was reported to be above 1500 m asl (Smith 1921), and Tran (2013) collected a specimen at 1515 m asl. Megophrys intermedia is assessed as Least Concern (IUCN 2017) and little is known about the reproductive behaviour and life history of the species. In Lam Dong Province (Vietnam), male M. intermedia call in March (Tran 2013); on the Langbian Plateau (Vietnam), male specimens are reported to call by day and by night from March to May and specimens called from within deep crevices between boulders in streams (Smith 1921); in Xe Kong Province (Laos), males call or guard egg clutches that are laid in water in July (Stuart 2005).

Integrative taxonomic analysis reveals a new species of Leptobrachium (Anura: Megophryidae) from north-eastern Cambodia and central Vietnam

ABSTRACT Species boundaries within the red-eyed Leptobrachium of southern Indochina have been uncertain. Leptobrachium pullum and L. mouhoti from upper and lower elevations, respectively, of the Langbian Plateau of southern Vietnam and eastern Cambodia differ in body size but have relatively low interspecific mitochondrial DNA divergence, leading to speculation that these might represent a single species with an elevational cline in body size. The recent discovery of an allopatric high-elevation population of red-eyed Leptobrachium on the Kon Tum Plateau (= Central Highlands) of north-eastern Cambodia and central Vietnam has been referred to both species, and to a putatively undescribed species. We examine variation in morphology of adults and tadpoles, mitochondrial DNA, 11 nuclear genes and advertisement calls, and show corroborating lines of evidence for the existence of three species of red-eyed Leptobrachium in southern Indochina. Although the three species are reciprocally monophyletic in mitochondrial DNA, their shallow mitochondrial DNA divergences are not mirrored by morphology, advertisement calls, or – in part – nuclear DNA, and probably reflect past mitochondrial introgression rather than recent speciation. The Central Highlands taxon is described herein as a new species. http://www.zoobank.org/urn:lsid:zoobank.org:pub:CE6650AF-D9FB-40F4-8A2E-9B4E23AAC205

A new species of Oligodon Fitzinger, 1826 from the Langbian Plateau, southern Vietnam, with additional information on Oligodon annamensis Leviton, 1953 (Squamata: Colubridae).

We describe a new species of Oligodon from the highlands of the Langbian Plateau, southern Truong Son Mountains, Vietnam, based on morphological and molecular phylogenetic analyses. The new species, Oligodon rostralis sp. nov is distinguished from its congeners by the following morphological characters: medium size in adults (male TL = 582 mm); small and broad head with long protruding snout; dorsal scale row formula 15-15-13; 167 ventrals, 47 subcaudals; single preocular, single postocular; loreal and presubocular absent; six supralabials, third and fourth entering orbit; six infralabials, anterior four contacting first pair of chin shields; internasals separate from prefrontals; nasal divided; single anterior and two posterior temporals; cloacal plate undivided; hemipenes short, bilobed, bifurcating in anterior one third of their length, extending to 8th subcaudal, lacking spines and papillae, with a prominent transverse flounces and distal calyces; six maxillary teeth, the posterior three enlarged; dorsal pattern consisting of 14+4 large dark-brown blotches and a bright-orange vertebral stripe on tail and dorsum; and ventral surfaces in life cream laterally with dark quadrangular spots; dark temporal streak present, edged with white. We also provide additional information on O. annamensis, including a morphological dataset of all specimens known from natural history collections and confirmation of an earlier record of O. annamensis from Cambodia. We also provide the first record of O. annamensis for Dak Lak Province. Phylogenetic analyses of mtDNA genes (3,131 bp of 12S rRNA, 16S rRNA and cyt b) suggest sister relationships of Oligodon rostralis sp. nov. and O. annamensis and place them in one clade with the O. cyclurus and O. taeniatus species groups, which is concordant with previous studies on the phylogenetic relationships of Oligodon. Our study demonstrates high level of herpetofaunal diversity and endemism of Langbian Plateau and further supports the importance of this area for conservation herpetofaunal diversity in Indochina.

A New Species of the Genus <i>Calamaria</i> Boie, 1827 from the Highlands of the Langbian Plateau, Southern Vietnam (Squamata: Colubridae)

A new species of reed snake, genus Calamaria, is described from the Langbian Plateau in Lam Dong and Khanh Hoa provinces, Vietnam based on a morphological examination of nine specimens. Calamaria strigiventris sp. nov. is distinguished from all congeners by a combination of the following morphological characters: 9 – 11 modified maxillary teeth; rostral wider than high; prefrontal shorter than frontal, touching first two supralabials; mental separated from anterior chin shields; dorsal scales in 13 – 13 – 13 rows, all smooth; single preocular, single postocular; four supralabials, the 2nd and 3rd in contact with the eye; eye diameter smaller than eye-mouth distance; five infralabials; six scales surrounding the paraparietal; prefrontal touching 1st – 2nd supralabials; ventral scales 130 – 183; subcaudal scales 20 – 33, paired; tail relatively short (8.4 – 17.9% of the total length), nearly as thick as body, slowly tapering anteriorly, then abruptly tapering to the tip; dorsal scales reducing to four rows above 17th subcaudal on tail; dorsum uniform gray-brown, venter bright yellow with three interrupted longitudinal black stripes, one wide in the middle and a pair on the lateral edges of the ventrals. The new species is currently known only from two localities on the Langbian Plateau and was recorded from montane elfin evergreen tropical forests of Lam Dong and Khanh Hoa provinces at elevations from 1500 to 2000 m a.s.l. We suggest the new species should be considered as Vulnerable (VU) following the IUCN’s Red List categories.

A new species of the genus Theloderma Tschudi, 1838 (Amphibia: Anura: Rhacophoridae) from Tay Nguyen Plateau, central Vietnam.

A new species of small tree frog from a primary montane tropical forest of central Vietnam, Tay Nguyen Plateau, is described based on morphological, molecular, and acoustic evidence. The Golden Bug-Eyed Frog, Theloderma auratum sp. nov., is distinguishable from its congeners and other small rhacophorid species based on a combination of the following morphological attributes: (1) bony ridges on head absent; (2) smooth skin completely lacking calcified warts or asperities; (3) pointed elongated tapering snout; (4) vocal opening in males absent; (5) vomerine teeth absent; (6) males of small body size (SVL 21.8–26.4 mm); (7) head longer than wide; ED/SVL ratio 13%–15%; ESL/SVL ratio 16%–20%; (8) small tympanum (TD/EL ratio 50%–60%) with few tiny tubercles; (9) supratympanic fold absent; (10) ventral surfaces completely smooth; (11) webbing between fingers absent; (12) outer and inner metacarpal tubercles present, supernumerary metacarpal tubercle single, medial, oval in shape; (13) toes half-webbed: I 2–2¼ II 1½–2¾ III 2–3¼ IV 3–1½ V; (14) inner metatarsal tubercle present, oval; outer metatarsal tubercle absent; (15) iris bicolored; (16) dorsal surfaces golden-yellow with sparse golden-orange speckling or reticulations and few small dark-brown spots; (17) lateral sides of head and body with wide dark reddish-brown to black lateral stripes, clearly separated from lighter dorsal coloration by straight contrasting edge; (18) ventral surfaces of body, throat, and chest greyish-blue with indistinct brown confluent blotches; (19) upper eyelids with few (3–5) very small flat reddish superciliary tubercles; (20) limbs dorsally reddish-brown, ventrally brown with small bluish-white speckles. The new species is also distinct from all congeners in 12S rRNA to 16S rRNA mitochondrial DNA fragment sequences (uncorrected genetic distance P>8.9%). Advertisement call and tadpole morphology of the new species are described. Our molecular data showed Theloderma auratum sp. nov. to be a sister species of Th. palliatum from Langbian Plateau in southern Vietnam.

Molecular, morphological and acoustic assessment of the genus Ophryophryne (Anura, Megophryidae) from Langbian Plateau, southern Vietnam, with description of a new species.

Asian Mountain Toads (Ophryophryne) are a poorly known genus of mostly small-sized anurans from southeastern China and Indochina. To shed light on the systematics within this group, the most comprehensive mitochondrial DNA phylogeny for the genus to date is presented, and the taxonomy and biogeography of this group is discussed. Complimented with extensive morphological data (including associated statistical analyses), molecular data indicates that the Langbian Plateau, in the southern Annamite Mountains, Vietnam, is one of the diversity centres of this genus where three often sympatric species of Ophryophryne are found, O. gerti, O. synoria and an undescribed species. To help resolve outstanding taxonomic confusion evident in literature (reviewed herein), an expanded redescription of O. gerti is provided based on the examination of type material, and the distributions of both O. gerti and O. synoria are considerably revised based on new locality records. We provide the first descriptions of male mating calls for all three species, permitting a detailed bioacoustics comparison of the species. We describe the new species from highlands of the northern and eastern Langbian Plateau, and distinguish it from its congeners by a combination of morphological, molecular and acoustic characters. The new species represents one of the smallest known members of the genus Ophryophryne. At present, the new species is known from montane evergreen forest between 700–2200 m a.s.l. We suggest the species should be considered Data Deficient following IUCN’s Red List categories.

Contribution to the fauna of Langbian plateau, Southern VietNam: Amphibians and reptiles of Hon Ba Nature Reserve (Khanh Hoa Province)

Contribution to the fauna of Langbian plateau, Southern VietNam: Amphibians and reptiles of Hon Ba Nature Reserve (Khanh Hoa Province)

A new species of Leptolalax (Anura: Megophryidae) from the western Langbian Plateau, southern Vietnam.

We describe a new species of megophryid frog from Loc Bac forest in the western part of the Langbian Plateau in the southern Annamite Mountains, Vietnam. Leptolalax pyrrhops sp. nov. is distinguished from its congeners by a combination of the following morphological attributes: (1) presence of distinct dark brown/black dorsolateral markings, including blackish spots on flanks and dark canthal and/or temporal streaks; (2) rudimentary webbing on toes; (3) tympanum externally distinct; (4) dorsal skin finely shagreened with numerous small tubercles and pustules; (5) medium size for the genus (30.3-33.9 mm in 2 adult males, 30.8-34.3 mm in 7 females); (6) grey-pinkish to dark brownish-violet chest and belly with numerous whitish speckles, also covering the lateral sides of body; (7) ventrolateral glands small, indistinct, do not form a distinct line; (8) pectoral glands comparatively small, comprising 1-3% of adult SVL; (10) iris bicolored, typically bright orange-red in upper two-thirds, fading to silvery green in lower third. The male advertisement call of the new species is also unique among those Leptolalax species for which calls are known, with a single long 'introductory' note, consisting of 5-12 pulses, followed by of 4-5 predominantly single-pulsed notes, and an average dominant frequency of 1.91-2.23 kHz. From the morphologically similar L. applebyi, L. melicus and L. bidoupensis, Leptolalax pyrrhops sp. nov. can be further distinguished by 13.5%, 13.7% and 10.3% sequence divergence at the 16S rRNA mtDNA gene. At present, the new species is known from montane evergreen forest between 800-1100 m elevation. We suggest the species should be considered as Data Deficient following IUCN's Red List categories. To date our finding represents the southernmost known record of the genus Leptolalax from Vietnam.

Rhacophorus vampyrus(Anura: Rhacophoridae) Reproductive Biology: A New Type of Oophagous Tadpole in Asian Treefrogs

We report on the reproductive biology of Rhacophorus vampyrus (Rhacophoridae, Anura) from the Lang Bian Plateau in southern Vietnam. Unlike most other members of the genus Rhacophorus, R. vampyrus is a phytotelm breeder and reproduces in water-filled tree hollows. The species shows a unique tadpole mouthpart morphology not reported for any other anurans: presence of a specific serrated horny arch on the upper jaw and two large, fang-like horny teeth on the lower jaw. This, together with the presence of a large extensible stomach and relatively short digestive tract length, indicates an adaptation toward macrophagous feeding. We observed two clutch types in R. vampyrus: fertilized eggs included in a typical foam nest and unfertilized eggs, apparently having a trophic function, enveloped by dense mucous. The digestive tracts of all tadpoles examined contained up to 40 trophic eggs and showed no remains of any other food. Keratinous mouthparts undergo considerable remodeling during tadpole development presuming the change of feeding mode in ontogeny. We speculate that these findings indicate that the tadpole of R. vampyrus is an obligatorily and highly specialized oophagous type with unique mouthpart structures. The advanced form of parental care, including the maternal provisioning of unfertilized eggs, is reported for the first time for the genus Rhacophorus and is the second documented record for the Rhacophoridae.

Two new cryptic species of the Cyrtodactylus irregularis complex (Squamata: Gekkonidae) from southern Vietnam

We describe two new species of the Cyrtodactylus irregularis complex both based on phylogenetic analysis of 654 bp of COImtDNA gene and morphological analyses of voucher specimens from Binh Phuoc and Lam Dong provinces, southern Vietnam.Cyrtodactylus bugiamapensis sp. nov. is described from the monsoon tropical forests of Bu Gia Map National Park, BinhPhuoc Province, and is distinguished from the remaining representatives of the C. irregularis complex by a combination of thefollowing characters: (1) size medium, with a maximum SVL of 76.8 mm; (2) original tail relatively thin, longer than body; (3)presence of enlarged femoral scales without femoral pores; (4) preclocal groove lacking; (5) 36–46 longitudinal rows of ventralscales at midbody; (6) males with 7–11 precloacal pores in an angular continuous series; (7) absence of enlarged subcaudals;(8) dorsal pattern consisting of a dark neck band which can be medially divided, and irregular dark brown spots with brightwhite edges. Cyrtodactylus bidoupimontis sp. nov. is described from mountainous evergreen tropical forests of Bidoup – NuiBa National Park, Lam Dong Province, and is most similar to C. irregularis sensu stricto from which it is distinguished by acombination of the following characters: (1) absence of enlarged, strongly keeled conical tubercles on the dorsal tail-base; (2)presence of flat rounded smooth to weakly keeled dorsal tubercles; (3) pallid dorsal head surface pattern lacking distinct darkbrown irregular spots with light edges; and (4) elongated limbs. Phylogenetic analyses revealed the presence of a number ofcryptic allopatric species within the C. irregularis complex. Long geological history and complicated relief of the Lang Bianplateau and surrounding areas might have shaped the present diversity within the C. irregularis complex. COI DNA-barcoding appears to be a useful tool to reveal cryptic diversity within the genus Cyrtodactylus.

Market turtle mystery solved in Vietnam

Asian turtles are overharvested for food, medicinal purposes and pets, and most species are now at risk of extinction (‘Asian turtle crisis’). As a result of high levels of trade, some species of Asian turtles are known to science mostly or only from animals found in trade. The Vietnamese box turtle ( Cuora picturata) was described in 1998 and is known only from markets. This species is likely to be highly threatened, and identifying the origin of this “market species” is imperative if it is to be conserved. We used evidence from phylogeny, biogeography and trade patterns to focus field searches for this species, and in July 2010–January 2011 found it in the wild at three localities on the Langbian Plateau of southern Vietnam. This discovery provides the first opportunity to conserve the Vietnamese box turtle, and provides hope for determining the wild origin of other rare Asian turtles that remain known only from commercial trade.

The Leptobrachium (Anura: Megophryidae) of the Langbian Plateau, southern Vietnam, with description of a new species

We sampled two forms of Leptobrachium in syntopy at the type locality of L. pullum at upper elevations on the Langbian Plateau, southern Vietnam. The two forms differed in morphology (primarily in coloration), mitochondrial DNA, and male advertisement calls. One form closely agrees with the type series of L. pullum (but not to its original description due to error), and the other is described as new. Leptobrachium leucops sp. nov. is distinguished from its congeners by having small body size (males with SVL 38.8–45.2), the upper one-third to one-half of iris white, a blue scleral arc, a dark venter, and sexually active males without spines on the upper lip. Leptobrachium pullum and L. mouhoti, a recently described species from low-elevation slopes of the Langbian Plateau in eastern Cambodia, are morphologically divergent but genetically similar, warranting further investigation into geographic variation in the red-eyed Leptobrachium of southern Indochina.

A new species of Leptolalax (Anura: Megophryidae) from southern Vietnam

We describe a new species of small megophryid frog from the Langbian Plateau in southern Vietnam, the southernmost record of Leptolalax from Vietnam. Leptolalax bidoupensis sp. nov. is distinguished from its congeners by a combination of a dark brownish red ventral surface with white speckling on entire ventral surface including throat, arms and legs, small size (23.6–24.6 mm in four adult males and 29.2–29.4 mm in two adult females), bicoloured iris (coppery red upper half, fading to pale silver ventrally), a mostly smooth skin texture with no skin ridges, and relatively short tibia (male TIB:SVL 0.44–0.46). The male advertisement call of the new species, consisting of 6–9 single-pulsed notes with a dominant frequency of 1.9–3.8 kHz, is also unique among Leptolalax species for which calls are known. From the morphologically similar L. applebyi and L. melicus, L. bidoupensis sp. nov. differs by 9.3% and 9.6% sequence divergence at the 16S mtDNA gene. At present, the new species is known from montane evergreen forest between 1620–1730 m elevation, within an area of 1 km 2 . We suggest the species should be considered Data Deficient following IUCN’s Red List categories.

Two new species of pitviper of the genus Cryptelytrops Cope 1860 (Squamata: Viperidae: Crotalinae) from Southeast Asia

We describe two new species of green pitviper from Southeast Asia that are morphologically similar to Cryptelytrops macrops, but can be distinguished from that species by genetic means, multivariate analysis of morphology and some aspects of coloration. Cryptelytrops cardamomensis sp. nov., is described from southeastern Thailand and the Cardamom Mountains of southwestern Cambodia. Cryptelytrops rubeus sp. nov. has been recorded from southern Vietnam and eastern Cambodia. These species have previously been confused with C. macrops, hence we also present here a redescription of this species, whose range is now restricted to Thailand, southern and central Laos, and northeastern Cambodia. All three species are present in Cambodia, but have disjunct ranges corresponding to three separate highland regions in southwestern (Cardamom Mountains), northeastern (western edge of the Kontum Plateau) and eastern (low elevation hills on the western edge of the Langbian Plateau) Cambodia for C. cardamomensis, C. macrops and C. rubeus respectively. However, there is still considerable morphological variation between geographically separated populations of C. macrops s.s., and greater sampling in southern and northern Thailand in particular may be required before the species diversity of this group is fully clarified.

A new tree frog of the genus Rhacophorus (Anura: Rhacophoridae) from southern Vietnam

We describe a new species of rhacophorid frog from the Langbian Plateau in southern Vietnam. Rhacophorus vampyrus sp. nov. is distinguished from its congeners by a combination of: a pale tan to brick red dorsum; white throat, chest and belly; black flanks and anterior and posterior surface of thighs; grey to black webbing between fingers and toes; reduced finger webbing; and pointed projection at tibiotarsal articulation. At present, the new species is known from montane evergreen forest between 1470–2004 m elevation. Rhacophorus vampyrus sp. nov. is a phytotelm breeder, depositing eggs in foam nests in small tree-holes.