Tao Thien Nguyen

Batrachochytrium salamandrivorans is the predominant chytrid fungus in Vietnamese salamanders

The amphibian chytrid fungi, Batrachochytrium dendrobatidis (Bd) and B. salamandrivorans (Bsal), pose a major threat to amphibian biodiversity. Recent evidence suggests Southeast Asia as a potential cradle for both fungi, which likely resulted in widespread host-pathogen co-existence. We sampled 583 salamanders from 8 species across Vietnam in 55 locations for Bsal and Bd, determined scaled mass index as a proxy for fitness and collected environmental data. Bsal was found within 14 of the 55 habitats (2 of which it was detected in 2013), in 5 salamandrid species, with a prevalence of 2.92%. The globalized pandemic lineage of Bd was found within one pond on one species with a prevalence of 0.69%. Combined with a complete lack of correlation between infection and individual body condition and absence of indication of associated disease, this suggests low level pathogen endemism and Bsal and Bd co-existence with Vietnamese salamandrid populations. Bsal was more widespread than Bd, and occurs at temperatures higher than tolerated by the type strain, suggesting a wider thermal niche than currently known. Therefore, this study provides support for the hypothesis that these chytrid fungi may be endemic to Asia and that species within this region may act as a disease reservoir.

Phylogeny of the Cyrtodactylus irregularis species complex (Squamata: Gekkonidae) from Vietnam with the description of two new species

The number of described species of bent-toed geckos of the Cyrtodactylus irregularis species complex in Vietnam has increased from one to eight in the last six years. We combined morphological and molecular analyses to explore phylogenetic relationships among all described species in the group. The phylogeny required the description of two new species, Cyrtodactylus phuocbinhensis sp. nov. and Cyrtodactylus taynguyenensis sp. nov. Further, the tree resolved two additional undescribed clades that may also be new species. The species C. bugiamapensis and C. ziegleri were found to require redefinition. Cyrtodactylus phuocbinhensis sp. nov. is characterized by a series of enlarged femoral scales separated from preanal scales while Cyrtodactylus taynguyenensis sp. nov. does not possess enlarged femoral scales. Both new species are distinguished from other congeners by a combination of the following characters: small subcaudal scales, not transversely enlarged; presence (C. phuocbinhensis sp. nov.) or absence (C. taynguyenensis sp. nov.) of enlarged femoral scales; number of preanal pores; and dorsal pattern. Genetic distances between described species and new species were 16.5% and 2.0% in COI and RPL35, respectively, for C. phuocbinhensis sp. nov., and these distances were 18.8% and 2.2% for C. taynguyenensis sp. nov., respectively.

A new species of Leptolalax (Anura: Megophryidae) from the highest mountain in Indochina

We describe a new species of Leptolalax from northern Vietnam. Leptolalax botsfordi sp. nov. is distinguished from its congeners by a combination of (1) supra-axillary and ventrolateral glands present; (2) dark brownish red ventral surface with white speckling; (3) medium body size for the genus (29.1-32.6 mm in 7 adult males, 30.0-31.8 mm in 2 females); (4) black markings on the flanks absent; (5) toes with rudimentary webbing and weak lateral fringing; (6) large pectoral glands (1.1-1.9 mm; 4-6% SVL) and femoral glands (2.4-4.3 mm; 7-14% SVL); and (7) an advertisement call with a dominant frequency of 2.6-3.2 kHz (at 14.0º C). At present, the new species is known only from upper montane forest between 2,795-2,815 m elevation on Mount Fansipan, Hoang Lien National Park. To our knowledge, Leptolalax botsfordi sp. nov. occurs at higher elevations than any other species in the genus. If L. botsfordi sp. nov. is truly restricted to a narrow, high-elevation band, it is likely to be particularly vulnerable to the effects of climate change. The new species also faces the immediate threat of habitat degradation and pollution due to tourist activity.

Review of the Genus Sphenomorphus Fitzinger, 1843 (Squamata: Sauria: Scincidae) in Vietnam, with Description of a New Species from Northern Vietnam and Southern China and the First Record of Sphenomorphus mimicus Taylor, 1962 from Vietnam

Abstract We describe a new forest skink species of the genus Sphenomorphus based on specimens from northern Vietnam and from Hainan Island, southern China. The new species is differentiated from the congeners by the combination of the following characters: size small (SVL 35.8–48.8 mm); prefrontals in contact with each other mesially; supralabials seven; primary temporals two; external ear opening present, without lobules, tympanum slightly sunk; midbody scales in 32–34 rows; dorsal scales smooth, paravertebral scales 65–72, not widened; limbs well developed, pentadactyl; 15–19 smooth lamellae under fourth toe; free margins of upper and lower eyelids edged in white; neck, dorsum, and tail base bronze-brown with a discontinuous dark vertebral stripe; upper lateral zone black, interrupted by small light spots from behind the neck. In addition, we provide a review of Vietnamese Sphenomorphus with the first country record of Sphenomorphus mimicus. The generic allocation of Sphenomorphus devorator (allocated to Scincella), Leptoseps tetradactylus (allocated to Sphenomorphus), and Livorimica bacboensis (allocated to Sphenomorphus) is discussed.

Habitat characterization and potential distribution of Tylototriton vietnamensis in northern Vietnam

The habitat preferences of the endemic Vietnam Crocodile Newt, Tylototriton vietnamensis were investigated on two scales: (1) at Yen Tu Nature Reserve, Bac Giang Province, Vietnam, while compiling information about pond occupancy and developing a qualitative comparison among breeding sites and (2) by developing a Species Distribution Model based on climate and land cover data identifying further suitable habitats in northern Vietnam. A factor analysis followed by a multiple linear regression showed 94% support for our occupancy ranking model. Our results suggest that T. vietnamensis preferentially inhabits small pools with long hydroperiod and pH above 4.3. Suitable areas for the species have higher incidence in northern regions, where undisturbed vegetation and temperature-related variables seem to make greater contributions. Additionally, these potentially suitable areas are strongly fragmented and only a few are under IUCN protection, increasing their vulnerability towards further degradation.

Trade in wild anurans vectors the urodelan pathogen Batrachochytrium salamandrivorans into Europe

Pathogen pollution has caused dramatic losses of amphibian diversity on a global scale. The recently emerged chytrid fungus Batrachochytrium salamandrivorans (Bsal) has been hypothesized to have its origin in Asian urodelan populations, from which it may have been introduced to Europe through the trade in live urodelans. We here show that Bsal is present on wild small-webbed fire-bellied toads (Bombina microdeladigitora) from Vietnam and on representatives of the same species that have recently been imported in Germany. This finding suggests that the installment of measures to mitigate the Bsal threat through the amphibian trade should not be limited to urodeles, but should equally take anurans into account.

The Vietnamese population of Megophrys kuatunensis (Amphibia: Megophryidae) represents a new species of Asian horned frog from Vietnam and southern China

The Asian frog genus Megophrys is a diverse group of morphologically conserved, forest-dwelling frogs. The genus harbours highly localised species diversification and new species continue to be described on a regular basis. We examined the taxonomic status of a population of Megophrys frogs from the Hoang Lien Range in northern Vietnam and southern China previously identified as M. kuatunensis (subgenus Panophrys). Preliminary phylogenetic analyses using a fragment of 16S rDNA places the species in question within the Megophrys (subgenus Panophrys) species group, a primarily Chinese radiation within the genus. On the basis of morphological, molecular and bioacoustic data, we conclude that this population does not represent M. kuatunensis, or any known species in the genus. We herein describe this species of Megophrys as new. Known only from Sa Pa District, Lao Cai Province in Vietnam and Jinping County, Yunnan Province in China, the new species is likely to be threatened by ongoing deforestation in the region. We provide an updated species description of M. kuatunensis based on type specimens, and suggest that M. kuatunensis is likely to be restricted to eastern China.

The breeding biologies of three species of treefrogs with hyperextended vocal repertoires (Gracixalus; Anura: Rhacophoridae)

Gracixalus gracilipes, G. quangi, and G. supercornutusare small, morphologically and molecularly similar treefrogs with green blood from Vietnam, Laos and southern China. The breeding biologies, eggs, embryos and larvae of these three species are poorly known, and the male advertisement call of only G. quangiis known; this species has a hyperextended vocal repertoire. We provide new information on the breeding habitats, eggs, embryos and tadpoles of these three species and describe the calls of G. gracilipesand G. supercornutus. All three species deposit egg clumps on leaves overhanging shallow pools and puddles in forests. Like G. quangi, the calls of G. gracilipesand G. supercornutusare non-stereotypical, with individual calls highly variable in structure, duration, amplitude and frequency. Both calls are frequency modulated and have a dominant frequency of 4.1-4.7 kHz and many harmonics. The functional significance of these variations is unknown, and it is not known how common hyperextended call repertoires are within the genus.

Taxonomic re-evaluation of the monotypic genus Pararhabdophis Bourret, 1934 (Squamata: Colubridae: Natricinae) with discovery of its type species, P. chapaensis, from China

The Asian monotypic genus Pararhabdophis Bourret, 1934 has long been known from a single holotype of the type species Pararhabdophis chapaensis Bourret, 1934 only. The limited available information hampered the identification of the natricine species. On the basis of eight newly collected specimens of P. chapaensis from the type locality in Sa Pa, Lao Cai Province, Vietnam and from Pingbian, Yunnan Province in southwestern China, the taxonomic position of the genus Pararhabdophis was re-evaluated using both morphological and molecular datasets for the first time. Pararhabdophis chapaensis is nested within the genus Hebius Thompson, 1913 with strong support, and morphologically indistinguishable from the latter genus. As a consequence, we herein synonymize the genus Pararhabdophis with Hebius and discuss about the existing paraphyly of some Hebius species. In addition we report Hebius chapaensis for the first time from China and provide redescription and natural history data of this poorly known species. To facilitate future taxonomic work, an identification key to all known natricine genera from China and Vietnam is also provided.

A new species of Limnonectes (Amphibia: Anura: Dicroglossidae) from Vietnam

A new species of Limnonectes is described from northeastern Vietnam based on morphological and molecular differences. Morphologically, the new species is distinguishable from its congeners on the basis of a combination of the following diagnostic characters: Large size (SVL 50.1-68.9 in males, 45.5-63.0 mm in females); males with moderately enlarged head (HL/SVL 0.48), head longer than wide; vomerine teeth present; external vocal sacs absent; rostral length short (RL/SVL 0.16 in males, 0.15 in females); tympanum distinct (TD/ED 0.63 in males, 0.60 in females); dorsal surface of head, body and flanks with flattened tubercles; dorsal surface of tibia possessing small tubercles; supratympanic fold present; dorsolateral fold absent; webbing formula I0-0II0-1/3III0-1/3IV1/2-0V; in life, dorsum yellowish brown with a dark brown marking; throat and chest white with dark brown marking; ventral surface of fore and hind limbs as well as belly white. In phylogenetic analyses, the new species is placed as the sister taxon to Limnonectes fujianensis with strong statistical support in all analyses.