Characterization of the Complete Mitochondrial Genome of the Central Highland Grey-Shanked Douc Langur (Pygathrix cinerea), a Critically Endangered Species Endemic to Vietnam (Mammalia: Primates).

The grey-shanked douc langur (Pygathrix cinerea) is a recently described, critically endangered primate, endemic to Vietnam. In this study, we describe the Central Highland species' complete mitochondrial genome (mitogenome-mtDNA). It is a circular molecule with a length of 16,541 base pairs (bp). The genome consists of 37 genes, consistent with those found in most other vertebrates, including 13 protein coding genes, 22 transfer RNAs, and two ribosomal RNAs. A comparison with the mitogenomes of more than 50 primates showed that the mitogenome of Vietnamese Central Highland Pygathrix cinerea has a conservative gene order. We identified 43 nucleotide differences when comparing this genome with a previously published mitogenome of Pygathrix cinerea. It is evident that there are distinct differences between the Pygathrix cinerea we are currently studying and other Pygathrix cinerea specimens. These differences are unlikely to be solely the result of sequencing errors, as the mitogenomes were generated using high-quality methods. The genetic divergence observed between the two Pygathrix cinerea mitogenomes implies the potential existence of at least two distinct lineages or forms of this primate species within its native range in Vietnam.

Dramatic dietary shift maintains sequestered toxins in chemically defended snakes.

Unlike other snakes, most species of Rhabdophis possess glands in their dorsal skin, sometimes limited to the neck, known as nucho-dorsal and nuchal glands, respectively. Those glands contain powerful cardiotonic steroids known as bufadienolides, which can be deployed as a defense against predators. Bufadienolides otherwise occur only in toads (Bufonidae) and some fireflies (Lampyrinae), which are known or believed to synthesize the toxins. The ancestral diet of Rhabdophis consists of anuran amphibians, and we have shown previously that the bufadienolide toxins of frog-eating species are sequestered from toads consumed as prey. However, one derived clade, the Rhabdophis nuchalis Group, has shifted its primary diet from frogs to earthworms. Here we confirm that the worm-eating snakes possess bufadienolides in their nucho-dorsal glands, although the worms themselves lack such toxins. In addition, we show that the bufadienolides of R. nuchalis Group species are obtained primarily from fireflies. Although few snakes feed on insects, we document through feeding experiments, chemosensory preference tests, and gut contents that lampyrine firefly larvae are regularly consumed by these snakes. Furthermore, members of the R. nuchalis Group contain compounds that resemble the distinctive bufadienolides of fireflies, but not those of toads, in stereochemistry, glycosylation, acetylation, and molecular weight. Thus, the evolutionary shift in primary prey among members of the R. nuchalis Group has been accompanied by a dramatic shift in the source of the species' sequestered defensive toxins.

Mitochondrial phylogeny of an Asian tree frog genus Theloderma (Anura: Rhacophoridae).

We assessed phylogenetic and systematic relationships among 17 out of 23 species of Theloderma and all three species of Nyctixalus from 2412bp sequences of the mitochondrial DNA genes of 12S rRNA, tRNA(val), and 16S rRNA using maximum likelihood and Bayesian inference methods. With the exception of T. moloch, Theloderma and Nyctixalus are confirmed to form a clade, in which each genus also forms a clade. Theloderma moloch is phylogenetically outside these clades and closer to samples from Chiromantis, Feihyla, Gracixalus, Kurixalus, Philautus, Polypedates, Raorchestes, and Rhacophorus. Within Theloderma, T. horridum and T. stellatum form the sister taxon to a clade comprising the remaining species. The basal split within the latter clade groups T. asperum, T. licin, T. petilum, and T. ryabovi as the sister to a clade comprising T. bicolor, T. chuyangsinense, T. corticale, T. gordoni, T. laeve, T. lateriticum, T. nebulosum, T. rhododiscus, and T. truongsonense. Our phylogenetic results indicate homoplastic evolution of four morphological characters: small vs. large body size, presence of vomerine teeth, presence of a vocal opening in males, and interdigital webbing on hands. The common ancestor of Theloderma and Nyctixalus is inferred to have arisen in the area including the current Sunda region.

Zhangixalusthaoae sp. nov., a new green treefrog species from Vietnam (Anura, Rhacophoridae).

We describe a new treefrog species from Lao Cai Province, northwestern Vietnam. The new species is assigned to the genus Zhangixalus based on a combination of the following morphological characters: (1) dorsum green, smooth; body size medium (SVL 30.1-32.2 in males); (2) fingers webbed; tips of digits expanded into large disks, bearing circum-marginal grooves; (3) absence of dermal folds along limbs; (4) absence of supracloacal fold and tarsal projection. The new species can be distinguished from its congeners by: (1) dorsal surface of the head and body green without spots; (2) axilla and groin cream with a black blotch; (3) ventral cream without spot; (4) chin creamy with grey marbling; anterior part of the thigh and ventral surface of tibia orange without spots; posterior parts of thigh orange with a large black blotch; (5) ventral side of webbing orange with some grey pattern (6) iris red-bronze, pupils black; (7) finger webbing formula I1»-1»II1-2III1-1IV, toe webbing formula I½-½II0-1½III»-1¾IV1¾-½V. Phylogenetically, the new species is nested in the same subclade as Z.jodiae, Z.pinglongensis, and Z.yaoshanensis, with genetic distances ranging from 3.23% to 4.68%. The new species can be found in evergreen montane tropical forests at an elevation of about 1,883 m a.s.l. This new discovery brings the number of known genus Zhangixalus species to 42 and the number of species reported from Vietnam to 10.

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.

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.

New record and dietary ecology of a poorly known frog, Amolopsshihaitaoi Wang, Li, Du, Hou & Yu, 2022 (Amphibia, Anura, Ranidae), from Ha Giang Province, Vietnam.

Background: The Hekou Torrent Frog (Amolopsshihaitaoi) was recently discovered from southern China and northern Vietnam in 2022. The knowledge about natural history and feeding ecology of this species is virtually lacking. New information: Based on our recent fieldwork in northern Vietnam, we report a new population of A.shihaitaoi from Ha Giang Province. In this study, we provide novel data on the diet of A.shihaitaoi, based on stomach content analyses of 36 individuals (17 males and 19 females). A total of 36 prey categories with 529 items, comprising 515 items of invertebrates and 14 unidentified items, were found in the stomachs of A.shihaitaoi. The dominant prey items of the species were Hymenoptera (Formicidae), Orthoptera (Acrididae), Lepidoptera (Lepidoptera other), Mantodea (Mantidae) and Araneae. The importance index (Ix) of prey categories ranged from 7.1% to 11.5%. Hymenoptera (Formicidae) had the highest frequency of prey items, found in 36 stomachs.

Southbound - the southernmost record of Tylototriton (Amphibia, Caudata, Salamandridae) from the Central Highlands of Vietnam represents a new species.

A new species of the genus Tylototriton is described from Ngoc Linh Mountain, Kon Tum Province, in the Central Highlands of Vietnam based on integrative taxonomy, namely by combining molecular and morphological evidence. Tylototritonngoclinhensissp. nov. differs from all other congeners based on morphological data, allopatric distribution, and molecular divergence. In terms of genetic divergence, Tylototritonngoclinhensissp. nov. distinctly differs from the sister species T.panhai (6.77%) and from T.ngarsuensis (12.36%) based on the mitochondrial NADH dehydrogenase subunit 2 (ND2) gene. Tylototritonngoclinhensissp. nov. is a moderate sized and robust salamander species with large cephalic edges, parotoids, and vertebral ridge orange in coloration. The new taxon differs from its congeners by a combination of the following morphological characteristics: size medium (SVL 60.8-66.5 mm, TL 57.6-61.8 mm in males, and SVL 72.5-75.6 mm, TL 62.9-67.9 mm in females); head longer than wide; parotoids very prominent and enlarged, projecting backwards; tail length shorter than snout-vent length; vertebral ridge large, high and glandular in appearance; 14 large and distinct dorsolateral glandular warts; gular fold present; tips of fore and hind limbs overlapping when adpressed along the body; tips of fingers reaching between eye and nostril when foreleg is laid forward; dorsal surface and lateral sides of the head, upper and lower lips, dorsolateral glandular warts, vertebral ridge, the peripheral area of the cloaca and the ventral edge of the tail orange in coloration; the presence of a distinct black line extending from the posterior end of the eye towards the shoulder. Tylototritonngoclinhensissp. nov. is restricted to evergreen montane forests near water bodies on Ngoc Linh Mountain. We suggest that the new species should be classified as Endangered (EN) in the IUCN Red List. This new important discovery represents the eighth Tylototriton taxon described from Vietnam, and at the same time constitutes the southernmost distributional record for the whole genus in Asia.

A new species of Vietnamophryne (Anura: Microhylidae) from Northeastern Vietnam.

A new species of the genus Vietnamophryne is described from Vietnam on the basis of two specimens collected from Tuyen Quang Province, Northeastern Vietnam. The new species is morphologically most similar to Vietnamophryne occidentalis from Thailand, however, it differs from the latter by having large black blotches in the lower jaw region, and a yellow-orange chest and belly. The genetic distance between the new species and other Vietnamophryne taxa is > 2.13% (16S mtDNA gene fragment). Vietnamophryne aurantifusca sp. nov. can be distinguished from all other species of Vietnamophryne by a combination of the following morphological characteristics: Size medium (SVL 17.618.2 mm in males); head wider than long; tympanum medium; finger I longer than half of finger II; dorsal skin relatively smooth with some round nodules, concentrated in the middle of the back, arranged along the length of the back, with a prominent ridge along the spine; Dorsum orangish-brown entirely and paler on margin of back with a small brownish ridge along the spine; sides brownish with creamy patches and orange spots; ventral surface orange, with grey marbling, most intense on the throat, ventral side of arms and thighs, and ventral surfaces of limbs dark grey with some orange spots.

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).

A new record of odd-scaled snake (Serpentes, Xenodermidae) from Vietnam: expanded description of Parafimbrios vietnamensis based on integrative taxonomy.

Based on the combination of molecular and morphological data, we herein report the second known finding of the xenodermid snake species Parafimbrios vietnamensis Ziegler, Ngo, Pham, Nguyen, Le & Nguyen, 2018. The male individual was found in the Yen Bai Province of northwestern Vietnam, more than 200 km from the type locality in Lai Chau Province. Genetic divergence between the newly-collected male and the holotype was low (1.7%), and is in agreement with morphological data that supports that they are conspecific. We give a detailed description of the morphological characters and coloration of the new record and provide an expanded diagnosis of P. vietnamensis. Parafimbrios is a poorly-understood genus, and our recent discovery brings the total number of known specimens of the genus to nine, 1/3 of them having been found in Vietnam (one specimen of P. lao and now two specimens of P. vietnamensis).

First description of the tadpole of Kurixalus baliogaster (Inger, Orlov, and Darevsky, 1999) (Anura: Rhacophoridae) from Vietnam, with comments on reproductive biology.

To date, 20 species of Kurixalus Ye, Fei, and Dubois have been described, and all of these species are distributed throughout South and Southeast Asia, from eastern India, throughout Myanmar and the mountainous regions of southern China, to Indochina, western and northern peninsular Thailand, Malaysia, Sumatra, Borneo, and the Philippines (Frost 2021). Descriptions of the tadpoles of only 6 species have been published: K. berylliniris and K. wangi Wu, Huang, Tsai, Li, Jhang, Wu (Wu et al. 2016); K. eiffingeri (Boettger) (Kuramoto Wang 1987); K. idiootocus (Kuramoto Wang) (Kuramoto Wang 1987); K. cf. verrucosus (Boulenger) (Ziegler Vences 2002), and Kurixalus yangi Yu, Hui, Rao, Yang (Humtsoe et al. 2020). A description of the tadpoles of K. baliogaster (Inger, Orlov, Darevsky) is also given in the species description (Inger et al. 1999), but described larvae are assigned tentatively to this species in the published text. Additional studies on the identification of the conspecificity of the described tadpoles with K. baliogaster have not been conducted. Based on the much larger size of the tadpole body (TL up to 40.3 mm), as well as the labial tooth row formula 6(26)/5(1) given by Inger et al. (1999), we concluded that these described tadpoles cannot be larval K. baliogaster and most likely belong to some other species of rhacophorid frogs.

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 daklakensis sp. nov. and Microhyla ninhthuanensis sp. 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.

Amolops caelumnoctis Rao amp; Wilkinson, 2007, a Junior Synonym of A. splendissimus Orlov amp; Ho, 2007 (Amphibia: Anura: Ranidae).

Amolops splendissimus Orlov and Ho, 2007 and A. caelumnoctis Rao and Wilkinson, 2007 were described almost simultaneously from either side of the China-Vietnam border. The two species share a strong morphological resemblance, and their taxonomic distinctiveness has been questioned, yet no one has confirmed the taxonomic relationship and status between the two taxa. To resolve this taxonomic issue, we collected additional topotypic and near-topotypic specimens of A. splendissimus and A. caelumnoctis from both China (A. caelumnoctis: Wenshan County, Yunnan Province; type locality Luchun County, Yunnan Province), and Vietnam (A. splendissimus: Tam Duong District, Lai Chau Province; type locality Mount Ky Quan San, Bat Xat, Lao Cai Province). Molecular analysis based on a 16S rRNA fragment revealed minimal genetic divergences between the two taxa (0.0%0.4% uncorrected p-distance), and both species are closely related to A. viridimaculatus (2.1%2.3%) and A. medogensis (3.5%3.7%). Morphological comparisons between the newly collected specimens and the original descriptions of both species further support the lack of distinctiveness of the two species, hence, we conclude that A. caelumnoctis is a junior synonym of A. splendissimus.

A new species of Megophrys (Amphibia: Anura: Megophryidae) from Vietnam.

A new species of Megophrys is described from Cao Bang Province, northeastern Vietnam based on morphological and molecular data. Morphologically, the new species is distinguishable from its congeners by a combination of the following characters: Size small (SVL 34.9-38.9 mm in males); tympanum visible; vomerine teeth absent; tongue not notched posteriorly; male with a single vocal sac; toes with rudimentary webbing; subarticular tubercles and lateral fringes absent on all digits; nuptial pads present on fingers I and II in males, with spicules; dorsal skin with scattered granules and tubercles; flank with tubercles; dorsum with a X-shaped dorsal ridge; dorsolateral folds prominent; a small horn-like tubercle present at the outer edge of the eyelid; dorsal surface yellowish brown with a dark brown triangle between the eyes, and a dark brown marking along the X-shaped ridge on the back. In the phylogenetic analyses, the new species is unambiguously nested within the subgenus Panophrys with interspecific uncorrected genetic p-distances (16S rRNA gene) varying from 4.26% (compared with M. rubrimera) to 10.80% (compared with M. acuta).

Integrative taxonomy reveals three new taxa within the Tylototriton asperrimus complex (Caudata, Salamandridae) from Vietnam.

The Tylototriton asperrimus complex from northern Vietnam is reviewed based on morphological comparisons and analysis of the mitochondrial marker NADH dehydrogenase subunit 2 (ND2). Based on molecular divergences, which were revealed to be higher than in other congeners, in concert with morphological differences, two new species and one subspecies are described herein: Tylototriton pasmansi sp. nov. differs from T. asperrimus sensu stricto by 3.2 to 3.6 % genetic divergence and a combination of distinct morphological characters, such as head slightly longer than wide, distinct mid-dorsal ridge, relatively wide distance between the eyes, tips of fingers reaching the eye when foreleg is laid forward, labial and gular folds present, central belly skin with tubercles shaped like transverse wrinkles and distinct, pointy to round rib nodules. The population of T. pasmansi sp. nov. consists of two subclades, the nominotypic one occurring on the eastern side of the Da River (or Black River, including Hoa Binh and Phu Tho provinces), and another occurring on the western side (including Son La and Thanh Hoa provinces). These two subclades differ by 2.5 to 3.1 % genetic divergence and distinct morphological characters. The western subclade is herein described as Tylototriton pasmansi obsti ssp. nov., which differs from the nominotypic form by a wider head, longer and narrower snout, shorter femur length, and an overall less granulose skin, without an increased concentration of warts on the body sides. A second new species, Tylototriton sparreboomi sp. nov. is described from Lai Chau Province. It differs from T. asperrimus sensu stricto by 4.1 to 4.2 % and from Tylototriton pasmansi sp. nov. by 3.6 to 4.5 % genetic divergences as well as by a combination of distinct morphological characters, such as head longer than wide, tips of fingers reaching nostril when foreleg adpressed along head, rib nodules distinct, round and relatively enlarged, and wide distance between the eyes.

First description of the tadpole of Theloderma ryabovi Orlov, Dutta, Ghate et Kent, 2006 (Anura: Rhacophoridae), an endemic mossy frog from Vietnam.

To date, 26 species of Theloderma have been described and all are distributed throughout Southeast Asia from Assam in northeastern India to Myanmar, Indochina, the Malay Peninsula, and the islands of the Greater Sundas: Sumatra and Borneo (Frost 2019). The tadpoles of only 12 species have been described and published: T. asperum (Boulenger); T. auratum Poyarkov, Kropachev, Gogoleva Orlov; T. bicolor (Bourret); T. corticale (Boulenger); T. gordoni Taylor; T. horridum (Boulenger); T. leave (Smith); T. moloch (Annandale); T. nebulosum Rowley, Le, Hoang, Dau Cao; T. palliatum Rowley, Le, Hoang, Dau Cao; T. stellatum Taylor; T. vietnamense Poyarkov, Orlov, Moiseeva, Pawangkhanant, Ruangsuwan, Vassilieva, Galoyan, Nguyen Gogoleva (Boulenger 1903; Annandale 1912; Wassersug et al. 1981; Inger et al. 1999; Leong Lim 2003; Inthara et al. 2005; Rowley et al. 2011; Gawor et al. 2012; Orlov et al. 2012; Poyarkov et al. 2015; Kropachev et al. 2018).

Three new species of the snake genus Achalinus from Vietnam (Squamata: Xenodermatidae).

Three new species of the xenodermatid genus Achalinus are described from northern Vietnam based on morphological and molecular evidence: Achalinus juliani sp. nov. is characterized by a combination of the following characters: 1) maxillary teeth 28; 2) suture between the internasals distinctly longer than that between the prefrontals; 3) internasal not fused to prefrontal; 4) loreal not fused with prefrontal; 5) infralabials 6; 6) mental separated from anterior chin shields; 7) two elongated anterior temporals, in contact with the eye, and two posterior temporals; 8) dorsal scales in 25-23-23 rows, keeled; 9) ventrals 173-179; 10) subcaudals 77-91, unpaired; 11) a total length of at least 413 mm (with a maximum tail length of 109 mm, and a tail/total length ratio of 0.22-0.37); 12) dorsum in preservative reddish to greyish brown above, with the lower and posterior head sides being paler; venter greyish cream, with the underside of the tail being somewhat darker. Achalinus timi sp. nov. is characterized by a combination of the following characters: 1) maxillary teeth 27; 2) suture between the internasals distinctly longer than that between the prefrontals; 3) loreal fused with the prefrontal on each side, with the prefrontal extending towards the supralabials; 4) dorsal scales in 25-25-23 rows, keeled; 5) ventrals 170+1; 6) subcaudals 72, unpaired; 7) a total length of at least 177.9 mm in males (with a tail length of 37.9 mm, and a tail/total length ratio of 0.21); 8) dorsum in preservative reddish to greyish brown above, with wide portion of the vertebral region being distinctly darker; the lower head sides somewhat paler; infralabial and chin shields light greyish brown; venter greyish cream, with the underside of the tail being somewhat darker and the chin region somewhat paler. Achalinus emilyae sp. nov. is characterized by a combination of the following characters: 1) maxillary teeth 27 or 28; 2) suture between internasals distinctly longer than that between the prefrontals; 3) internasal not fused to prefrontal; 4) loreal not fused with prefrontal; 5) infralabials 5; 6) mental separated from anterior chin shields; 7) two anterior temporals, only the upper one in contact with eye, and two posterior temporals; 8) dorsal scales in 23-23-23 rows, keeled; 9) ventrals in females 157-161; 10) subcaudals in females 63, unpaired; 11) a total length of at least 519.5 mm (with a maximum tail length of 95.1 mm, and a tail/total length ratio of 0.18 in females); 12) dorsum iridescent pale yellowish brown with a dark longitudinal mid-dorsal stripe. In terms of pairwise genetic distance (cytochrome c oxidase subunit 1, COI), the three new species differ by at least 12.7% from other members of the genus, including themselves. The total number of Achalinus known is increased to twelve and the number of Achalinus species known from Vietnam is increased from three to six. Currently ten species of xenodermatids are known to exist in Vietnam: Achalinus ater, A. emilyae, A. juliani, A. rufescens, A. spinalis, A. timi, Fimbrios klossi, F. smithi, Parafimbrios lao, and P. vietnamensis.

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.

Evolution of nuchal glands, unusual defensive organs of Asian natricine snakes (Serpentes: Colubridae), inferred from a molecular phylogeny.

A large body of evidence indicates that evolutionary innovations of novel organs have facilitated the subsequent diversification of species. Investigation of the evolutionary history of such organs should provide important clues for understanding the basis for species diversification. An Asian natricine snake, Rhabdophis tigrinus, possesses a series of unusual organs, called nuchal glands, which contain cardiotonic steroid toxins known as bufadienolides. Rhabdophis tigrinus sequesters bufadienolides from its toad prey and stores them in the nuchal glands as a defensive mechanism. Among more than 3,500 species of snakes, only 17 Asian natricine species are known to possess nuchal glands or their homologues. These 17 species belong to three nominal genera, Balanophis, Macropisthodon, and Rhabdophis. In Macropisthodon and Rhabdophis, however, species without nuchal glands also exist. To infer the evolutionary history of the nuchal glands, we investigated the molecular phylogenetic relationships among Asian natricine species with and without nuchal glands, based on variations in partial sequences of Mt-CYB, Cmos, and RAG1 (total 2,767 bp). Results show that all species with nuchal glands belong to a single clade (NGC). Therefore, we infer that the common ancestor of this clade possessed nuchal glands with no independent origins of the glands within the members. Our results also imply that some species have secondarily lost the glands. Given the estimated divergence time of related species, the ancestor of the nuchal gland clade emerged 19.18 mya. Our study shows that nuchal glands are fruitful subjects for exploring the evolution of novel organs. In addition, our analysis indicates that reevaluation of the taxonomic status of the genera Balanophis and Macropisthodon is required. We propose to assign all species belonging to the NGC to the genus Rhabdophis, pending further study.