Sabira S. Idiiatullina

A new species of the genus Ovophis Burger in Hoge & Romano-Hoge, 1981, is described from the Langbian Plateau, southern Vietnam, based on an integrative taxonomic approach combining morphological and molecular evidence. Ovophis langbianus sp. nov . is distinguished from its congeners by a unique combination of diagnostic morphological characters and by significant genetic divergence in the mitochondrial cytochrome b gene. Phylogenetic analyses recover the new species as the sister lineage of O. tonkinensis (Bourret), from which it differs in body proportions, head morphology, color pattern, and several meristic characters. Multivariate analyses of morphological variation further support the distinctiveness of the new species, with specimens of Ovophis langbianus sp. nov . and O. tonkinensis forming two well-separated groups in morphospace and exhibiting significant differences in centroid positions. The new species is currently known only from montane evergreen forests of the Langbian Plateau at elevations of approximately 800–2,230 m asl. The recognition of Ovophis langbianus sp. nov . further emphasizes the taxonomic complexity of the O. tonkinensis species group and, together with previous molecular evidence for a distinct Cao Bang (Vietnam)-Guangxi (China) lineage, highlights the need for a comprehensive reassessment of species boundaries within the complex.

Hebius atemporalis (Bourret, 1934) has been reported from both northern Vietnam and southern China. Previous studies revealed deep genetic divergence between the Chinese and Vietnamese populations; however, no comprehensive taxonomic revision has examined the phylogenetic relationships and taxonomic status of these divergent lineages. Here, we present an integrative taxonomic reassessment of the H. atemporalis complex, combining detailed morphological comparisons and molecular data. As a result, we identify and describe a distinct new species, Hebius malnatei sp. nov ., endemic to the Yunnan-Guizhou Plateau, China. The new species can be distinguished from H. atemporalis sensu stricto by its larger adult body size, shorter relative tail length, higher numbers of ventrals and subcaudals, and distinctive coloration characterized by the absence of a nuchal collar. Phylogenetic analyses based on cytochrome b sequences consistently recover Hebius malnatei sp. nov . as the sister taxon of H. atemporalis s. str., with uncorrected p -distances of 8.0–9.8%. According to the IUCN Red List criteria, we recommend assigning Hebius malnatei sp. nov . to the category Least Concern (LC). This study highlights the need for taxonomic revision of widely distributed Hebius species and underscores the role of the Yunnan-Guizhou Plateau uplift in promoting species diversification.

The reed snakes of the genus Calamaria H. Boie in F. Boie are among the least-studied Southeast Asian snakes, with several taxa known only from their original description. Calamaria pavimentata annamensis Bourret, 1937, described from “Dong Tam Ve (province de Quang-tri), Annam”, now Bac Huong Hoa Nature Reserve, Quang Tri Province, Vietnam, based solely on a single specimen. This taxon was subsequently treated as a junior synonym of C. pavimentata Duméril, Bibron & Duméril, for example by Smith (1943) and Inger & Marx (1965), without any comprehensive reassessment to date. Here, we report the rediscovery of this taxon based on three newly collected specimens from the type locality and revalidate it as Calamaria annamensis stat. nov., based on integrative morphological and mitochondrial DNA analyses. We established detailed morphological comparisons to specimens of C. pavimentata alleged to originate from Java Island, Indonesia (type locality), and from Guangxi Province, China (as defined by Yeung et al. 2022), and other congeners from mainland Southeast Asia. Mitochondrial DNA (cytochrome b) analysis supports the distinctiveness of Calamaria annamensis stat. nov., revealing an uncorrected p-distance of 19.4% from C. pavimentata and ranging from 16.7% (C. nebulosa Lee) to 21.5% (C. lumbricoidea Boie) when compared with other congeners. This revalidation increases the number of Calamaria species to 71, of which twelve are currently recorded from Vietnam. Our findings also underscore the urgent need for comprehensive taxonomic and molecular studies on the widely distributed Calamaria pavimentata and C. septentrionalis Boulenger species complexes in Vietnam to resolve their true diversity and distribution.

A new species of the genus Gonyosoma Wagler is described from Vietnam and Laos, based on an integrative approach combining morphological and molecular evidence. Gonyosoma iadinum sp. nov. is distinguished from its congeners by a unique combination of diagnostic characters. It differs from its morphologically closest relative, Gonyosoma coeruleum Liu, Hou, Lwin, Wang & Rao, in the structure of the cloacal plate and hemipenes, as well as in significant genetic divergence in the cytochrome b (cyt b) mitochondrial DNA (mtDNA) gene sequences (p > 8.1%). The new species is currently known from central and southern Vietnam and central and southern Laos, where it has been recorded in montane evergreen forests of the Kon Tum-Gia Lai Plateau and the Langbiang Plateau in Vietnam. In Laos, it has been documented in Khammouan Province and the Bolaven Plateau. The species inhabits elevations ranging from 655 to 1,550 m above sea level. Further studies are required to reassess the taxonomic status of the Gonyosoma prasinum complex, particularly in Hainan Island, China. Based on its known distribution and available data, we suggest that the new species should be classified as Least Concern (LC) under the IUCN Red List criteria. We also provide an updated taxonomic key for the Gonyosoma species.

We describe a new species of green pitviper from the northern part of Central Thailand based on morphological and molecular (2406 bp from cyt b, ND4, and 16S rRNA mitochondrial DNA genes fragments) lines of evidence. Trimeresurus cryptographicus sp. nov. is distinguished from its congeners by the combination of the following morphological characters: small size, maximum known SVL of 523 mm; dorsal scales in 23(22)-21-15 rows, moderately keeled except the outermost rows; ventral scales 171–178; subcaudal scales 57–73, all paired; iris golden yellow in both sexes; body uniformly bright grass-green with indistinct serrated dark transverse markings in adults (499–523 mm SVL) but neonates and juveniles (231–245 mm SVL) have prominent irregular, serrated dark grey crossbands on a light green dorsum; suborbital stripe bluish-white and thin in male, absent in females; ventrolateral stripe, white, distinct, present on the first two dorsal scale rows in both sexes; throat, chin, and lower labials pale blue; ventral surfaces greenish-yellow; tail light brick-red mottled with dark spots, ventral side of the tail with white markings. While the new species differs from the morphologically similar species Trimeresurus macrops by a notable divergence in mitochondrial DNA sequences, it is more closely related to T. kuiburi (p = 1.7% for cytochrome b, p = 1.6% for 16S rRNA, and p = 1.8% for ND4 gene fragments). The new species is currently known only from low elevation in tropical limestone forest of Phitsanulok Province, in the northern part of central Thailand (ca. 100 m a.s.l.). This discovery further underlines the importance of limestone massifs of Indochina as local centres of herpetofaunal diversity and endemism.

The pitviper species Trimeresurus caudornatus was recently described based on only two specimens from Nabang Town, Yingjiang County, Yunnan Province, China. Here, we provide additional data on this species based on a re-examination of 19 preserved specimens, 16 specimens reported in earlier literature sources, and additional photo-documented records from northern Myanmar (Burma) and adjacent China. All new specimens were previously identified as Trimeresurus albolabris sensu lato or Trimeresurus septentrionalis sensu lato. Molecular analyses based on mitochondrial DNA supported the morphological findings in establishing conspecificity with T. caudornatus. The newly identified specimens have a pairwise distance of only 0.4–2.6% from those of the type series of T. caudornatus (based on the cytochrome b gene). Based on these findings, we confirm the presence of T. caudornatus from Myanmar and update its diagnostic characters and distribution. We suggest the species should be considered as Least Concern (LC) following the IUCN’s Red List categories. Further studies reassessing the populations of the Trimeresurus albolabris complex are required.

We describe a new species of green pitviper from southern and central parts of coastal Vietnam based on morphological and molecular (2406 bp from cyt b, ND4, and 16S rRNA mitochondrial DNA genes) lines of evidence. Trimeresurus cyanolabris sp. nov. is distinguished from its congeners by the combination of the following morphological characters: small size, maximum known SVL of 638 mm; dorsal scales in 21 (rarely 23)–21–15 rows, moderately keeled except the outermost rows; ventral scales 166–178; subcaudal scales 52–75, all paired; hemipenis forked, calyculate, reaching the 8th subcaudal; eye bright yellow in both sexes; dorsal surface deep green lacking cross-bands; postocular white stripe missing in both sexes; ventrolateral stripe faintly present on the first few dorsal scale rows in males, absent in females; throat, chin, and lower labials in shades of blue. The new species forms a distinct clade on the phylogenetic tree of the genus Trimeresurus and differs from the morphologically similar T. rubeus by a significant divergence in cytochrome b mitochondrial DNA gene sequences (p = 6.0%). The new species is currently known from low- to mid-elevations (ca. 90–400 m a.s.l.) in tropical forests of central-southern Vietnam. This discovery further underlines the importance of this area as a local center of herpetofaunal diversity and endemism, which is under great threat of deforestation.

Despite recent progress in our understanding of diversity within the genus Trimeresurus Lacépède, 1804, the subgenus Popeia Malhotra & Thorpe, 2004, distributed across most parts of East and Southeast Asia, remains taxonomically challenging. We applied an integrative taxonomic approach including analyses of morphological data and four mitochondrial genes (12S and 16S rRNA, cytochrome b, and NADH dehydrogenase subunit 4), along with examination of available type material, to address longstanding taxonomic questions in one clade within Popeia, the T. popeiorum group, and reveal a high level of hidden diversity of these snakes in the Indo-Burma Biodiversity Hotspot. We confirm that T. popeiorum Smith, 1937 sensu stricto is restricted to Northeast India, eastern Nepal, southern Bhutan, southeastern Bangladesh, western Yunnan Province (China), and northern and southwestern Myanmar. We further confirm that the recently described species T. yingjiangensis Chen et al., 2019 is a junior synonym of T. popeiorum. In addition, we discovered that the combination Trimesurus [sic] elegans Gray, 1853 is a valid senior synonym of T. popeiorum and threatens the stability of the latter taxon. Therefore, in order to protect the nomen popeiorum and in accordance with Article 23.9 of the International Code of Zoological Nomenclature, we regard the taxon Trimesurus elegans as a nomen oblitum and render Trimeresurus popeiorum a nomen protectum. Examination of a larger series of specimens allows us to describe two new cryptic species of Trimeresurus from the Indo-Burma Region. This study brings the total number of species in the subgenus Popeia to six and also suggests that the subspecific taxonomy of the T. sabahi complex requires further investigation. We urge adequate actions regarding the conservation of the newly discovered species and recommend further studies on their toxicology.

We describe a new species of karst-dwelling pitviper from Chumphon Province of Peninsular Thailand, in the Isthmus of Kra, based on morphological and molecular data (2427 bp from cyt b, ND4 and 16S rRNA mitochondrial DNA genes). Morphologically, Trimeresurus kraensis sp. nov. is distinguished from other congeners by the following combination of morphological characters: a dark/bottle-green dorsum with reddish-brown or purple crossbands; pale green venter lacking dark dots; stripes present on the lateral sides of the ventrals; internasals generally in contact; one large supraocular scale on each side of the head; iris pale copper; tail brown with dark purplish-brown crossbars; dorsal scales in 21–21–15 rows; ventral scales 167 in a single male, 169–171 in females; subcaudal scales 62 in a single male, 52–54 in females, all paired. White vertebral spots present in males, located on approximately every two or four dorsal scales; dark brown spots forming discontinuous pattern present on 1–3 lateral dorsal scale rows; males with reddish-brown postocular stripe with jagged edges. The new species differs from the morphologically similar species Trimeresurus venustus s. str. by a notable divergence in cytochrome b mitochondrial DNA gene sequences (p = 5.9%).

An integrative taxonomic analysis recovers a distinctive new species of the gekkonid genus Cyrtodactylus Gray, 1827 from Satun Province in extreme southern Thailand as the sister species to the Cyrtodactylus intermedius group of southern Indochina, approximately 600 km to the northeast across the Gulf of Thailand. Based on 1449 base pairs of the mitochondrial gene NADH dehydrogenase subunit 2 (ND2) and its flanking tRNAs, the new species, C. disjunctus sp. nov., bears a pairwise sequence divergence from the mean divergences of the intermedius group species ranging from 17.9–23.6%. Three different principal component analyses (PCA) and a multiple factor analysis (MFA) recover C. disjunctus sp. nov. as a highly distinctive karst cave-adapted species based on morphology and color pattern. Its sister species relationship to the intermedius group—to which it is added here—further underscores a growing body of analyses that have recovered a trans-Gulf of Thailand connection across the submerged Sunda Shelf between the southern Thai-Malay Peninsula and southern Indochina. Fragmented karstic archipelagos stretching across Indochina have served as foci for the independent evolution of nearly 25% of the species of Cyrtodactylus. The description of C. disjunctus sp. nov. continues to highlight the fact that karstic habitats support an ever-increasing number of threatened site-specific endemics that compose much of the reptile diversity of many Asian nations but, as of yet, most of these landscapes have no legal protection.