A new limestone-dwelling species of Micryletta (Amphibia: Anura: Microhylidae) from northern Vietnam

Singapore's herpetofauna: updated and annotated checklist, history, conservation, and distribution

Given Singapore's location at the confluence of important maritime trading routes, and that it was established as a British East India Company trading post in 1819, it is unsurprising that Singapore has become one of the centres of natural history collecting and research in Southeast Asia. Despite its small size, Singapore is home to a diverse herpetofauna assemblage and boasts a rich herpetological history. The first systematic studies of Singapore's herpetofauna (within the Linnaean binomial framework) date back to Stamford Raffles and the naturalists hired by him who first came to the island in 1819. Specimens that were collected during and after this time were deposited in museums worldwide. Over time, 39 species from Singapore were described as new to science. Due to the entrepôt nature of Singapore with its associated purchasing and trading of specimens (both alive and dead), poor record-keeping, and human introductions, numerous extraneous species from outside of Singapore were reported to occur on the island. Such issues have left a complicated legacy of ambiguous records and taxonomic complications concerning the identity of Singapore's species-rich herpetofauna, many of which were only resolved in the past 30-40 years. By compiling a comprehensive collection of records and publications relating to the herpetofauna of Singapore, we construct an updated and more accurate listing of the herpetofauna of Singapore. Our investigation culminated in the evaluation of 309 species, in which we compiled a final species checklist recognising 166 species (149 native and 17 non-native established species). Among the 149 native species are two caecilians, 24 frogs, one crocodilian, 13 turtles (three visitors), 34 lizards, and 75 snakes. Of the 17 non-native species are five frogs, four turtles, six lizards, and two snakes. The remaining 143 species represent species to be excluded from Singapore's herpetofauna species checklist. For each of the 309 species examined, we provide species accounts and explanatory annotations. Furthermore, we discuss Singapore's herpetofauna from a historical and conservation perspective. Immediate deforestation and nationwide urbanisation following colonisation completely eliminated many species from throughout much of the country and restricted them to small, degraded forest patches. We hope this publication highlights the importance of publishing observations and serves as a valuable resource to future researchers, naturalists, biological consultants, and policy makers in initiating studies on species ecology, distribution, status, and promoting conservation efforts to safeguard Singapore's herpetofauna.

Assessment of the threat status of the amphibians in Vietnam - Implementation of the One Plan Approach

The current decline in global biodiversity is most evident in amphibians with 41% percent of all species worldwide classified as threatened with extinction. Hence, a major challenge in amphibian conservation is the high number of threatened species, leading to a common approach of identifying priority species and regions for conservation efforts. As a part of one of 36 globally designated biodiversity hotspots, Vietnam is considered to be of particular importance for conservation action. To improve amphibian conservation in Vietnam, this study provides an updated species list and assesses their threat status by compiling data from a variety of sources. Furthermore, a Zoological Information Management System (ZIMS) analysis was conducted to determine the representation of extant amphibians from Vietnam in zoos worldwide. The batrachofauna of Vietnam is characterized by a high level of species richness and local endemism as well as a high rate of new discoveries, with more than half of the endemic species reported exclusively from their type locality, making them especially vulnerable to extinction. Up to 18% of all amphibians extant in Vietnam and 28% of endemic species are classified as threatened with extinction by the IUCN. In many cases, the IUCN Red List status is either missing or outdated, highlighting the urgent need of action. Around 14% of endemic amphibian species have been recorded exclusively from unprotected areas, suggesting prioritization for further research and conservation measures. The continuing decline in many species remains an unresolved problem. As a guide for future research and conservation measures, a list of the top 57 species was compiled. In addition, according to the ZIMS analysis, only 8% of threatened and 3% of endemic amphibian taxa from Vietnam are currently kept in zoos worldwide, and a richness analysis revealed that the highest density of husbandries is found in Europe and North America. To achieve maximum outcome for the conservation of threatened species, this study recommends a general shift by zoos towards maintaining species in greater need of captive assurance populations and breeding programs to support integrative strategies that combine in situ and ex situ conservation efforts following the IUCN’s One Plan Approach.

An integrative taxonomic revision of slug-eating snakes (Squamata: Pareidae: Pareineae) reveals unprecedented diversity in Indochina

Slug-eating snakes of the subfamily Pareinae are an insufficiently studied group of snakes specialized in feeding on terrestrial mollusks. Currently Pareinae encompass three genera with 34 species distributed across the Oriental biogeographic region. Despite the recent significant progress in understanding of Pareinae diversity, the subfamily remains taxonomically challenging. Here we present an updated phylogeny of the subfamily with a comprehensive taxon sampling including 30 currently recognized Pareinae species and several previously unknown candidate species and lineages. Phylogenetic analyses of mtDNA and nuDNA data supported the monophyly of the three genera Asthenodipsas, Aplopeltura, and Pareas. Within both Asthenodipsas and Pareas our analyses recovered deep differentiation with each genus being represented by two morphologically diagnosable clades, which we treat as subgenera. We further apply an integrative taxonomic approach, including analyses of molecular and morphological data, along with examination of available type materials, to address the longstanding taxonomic questions of the subgenus Pareas, and reveal the high level of hidden diversity of these snakes in Indochina. We restrict the distribution of P. carinatus to southern Southeast Asia, and recognize two subspecies within it, including one new subspecies proposed for the populations from Thailand and Myanmar. We further revalidate P. berdmorei, synonymize P. menglaensis with P. berdmorei, and recognize three subspecies within this taxon, including the new subspecies erected for the populations from Laos and Vietnam. Furthermore, we describe two new species of Pareas from Vietnam: one belonging to the P. carinatus group from southern Vietnam, and a new member of the P. nuchalis group from the central Vietnam. We provide new data on P. temporalis, and report on a significant range extension for P. nuchalis. Our phylogeny, along with molecular clock and ancestral area analyses, reveal a complex diversification pattern of Pareinae involving a high degree of sympatry of widespread and endemic species. Our analyses support the "upstream" colonization hypothesis and, thus, the Pareinae appears to have originated in Sundaland during the middle Eocene and then colonized mainland Asia in early Oligocene. Sundaland and Eastern Indochina appear to have played the key roles as the centers of Pareinae diversification. Our results reveal that both vicariance and dispersal are responsible for current distribution patterns of Pareinae, with tectonic movements, orogeny and paleoclimatic shifts being the probable drivers of diversification. Our study brings the total number of Pareidae species to 41 and further highlights the importance of comprehensive taxonomic revisions not only for the better understanding of biodiversity and its evolution, but also for the elaboration of adequate conservation actions.

Contributions to the biodiversity of Vietnam – Results of VIETBIO inventory work and field training in Cuc Phuong National Park

VIETBIO [Innovative approaches to biodiversity discovery and characterisation in Vietnam] is a bilateral German-Vietnamese research and capacity building project focusing on the development and transfer of new methods and technology towards an integrated biodiversity discovery and monitoring system for Vietnam. Dedicated field training and testing of innovative methodologies were undertaken in Cuc Phuong National Park as part and with support of the project, which led to the new biodiversity data and records made available in this article collection.

VIETBIO is a collaboration between the Museum für Naturkunde Berlin – Leibniz Institute for Evolution and Biodiversity Science (MfN), the Botanic Garden and Botanical Museum, Freie Universität Berlin (BGBM) and the Vietnam National Museum of Nature (VNMN), the Institute of Ecology and Biological Resources (IEBR), the Southern Institute of Ecology (SIE), as well as the Institute of Tropical Biology (ITB); all Vietnamese institutions belong to the Vietnam Academy of Science and Technology (VAST).

The article collection "VIETBIO" (https://doi.org/10.3897/bdj.coll.63) reports original results of recent biodiversity recording and survey work undertaken in Cuc Phuong National Park, northern Vietnam, under the framework of the VIETBIO project. The collection consist of this “main” cover paper – characterising the study area, the general project approaches and activities, while also giving an extensive overview on previous studies from this area – followed by individual papers for higher taxa as studied during the project. The main purpose is to make primary biodiversity records openly available, including several new and interesting findings for this biodiversity-rich conservation area. All individual data papers with their respective primary records are expected to provide useful baselines for further taxonomic, phylogenetic, ecological and conservation-related studies on the respective taxa and, thus, will be maintained as separate datasets, including separate GUIDs also for further updating.

Diversity, distribution and molecular species delimitation in frogs and toads from the Eastern Palaearctic

Biodiversity analyses can greatly benefit from coherent species delimitation schemes and up-to-date distribution data. In this article, we have made the daring attempt to delimit and map described and undescribed lineages of anuran amphibians in the Eastern Palaearctic (EP) region in its broad sense. Through a literature review, we have evaluated the species status considering reproductive isolation and genetic divergence, combined with an extensive occurrence dataset (nearly 85k localities). Altogether 274 native species from 46 genera and ten families were retrieved, plus eight additional species introduced from other realms. Independent hotspots of species richness were concentrated in southern Tibet (Medog County), the circum-Sichuan Basin region, Taiwan, the Korean Peninsula and the main Japanese islands. Phylogeographic breaks responsible for recent in situ speciation events were shared around the Sichuan Mountains, across Honshu and between the Ryukyu Island groups, but not across shallow water bodies like the Yellow Sea and the Taiwan Strait. Anuran compositions suggested to restrict the zoogeographical limits of the EP to East Asia. In a rapidly evolving field, our study provides a checkpoint to appreciate patterns of species diversity in the EP under a single, spatially explicit, species delimitation framework that integrates phylogeographic data in taxonomic research.

A new species of Micryletta Dubois, 1987 (Anura, Microhylidae) from Yunnan Province, China

A new species of the genus Micryletta Dubois, 1987 is described from Yunnan Province, China, based on morphological and molecular analyses. The most obvious differences between the new species and other species of this genus are small body size, unique coloration, and relatively longer hind limbs. In 16S rRNA gene sequences, the new species is diverged from all other congeners by 3.1%–8.0%.

Genetic diversity of the Pegu Rice Frog, Microhyla berdmorei (Anura: Microhylidae) based on mitochondrial DNA

The Pegu Rice Frog, Microhyla berdmorei is distributed across ten Asian countries. However, the DNA barcoding information (COI gene) is restricted to only Southeast Asian countries. Here, we sampled a specimen of M. berdmorei in Mizoram state, northeast India to allow the genetic diversity of the species across its range. We generated both COI and 16S ribosomal RNA sequences of the studied species to check the population genetic diversity. The Bayesian analyses clearly discriminate M. berdmorei from its sister species Microhyla pulchra. The present datasets of M. berdmorei also revealed 11 and 19 haplotypes with high uncorrected pairwise genetic distances in COI (3.8-11.8%) and 16S rRNA (0-4.6%) gene, respectively. Owing to the high intra-species genetic distances and different haplotypes with sufficient mutational steps in both mitochondrial genes, this study affirms the existence of M. berdmorei species complex or cryptic diversity within its range distribution in South and Southeast Asia.

A new species of the genus Micryletta (Anura, Microhylidae) from Hainan Island, China

We report on a new amphibian species of the genus Micryletta from Hainan Island, China, based on morphological and molecular analyses. The new species, Micryletta immaculatasp. nov., is diagnosed by a combination of the following morphological characters: medium-sized within genus (SVL 23.3–24.8 mm in males, n=3; 27.7–30.1 mm in females, n=2); dorsum bronze brown to reddish brown in life; dark brown spots and stripes on dorsum and flank absent; flanks largely pigmented with silver white; throat in adult males dark brown; undersides without dark patterns; outer metatarsal tubercle absent; supratympanic fold distinct; webbing between toes basal and poorly developed; tibiotarsal articulation adpressed limb reaching level of tympanum. The new species is divergent from all other congeners based on 16S rRNA gene sequences (3.0%–7.7%). Data on the natural history and male advertisement calls of the new species are provided. Following the IUCN Red List Categories and Criteria, we propose the new species to be listed as Vulnerable B1ab (iii).

A new species of Micryletta (Amphibia: Microhylidae) from southern Thailand

We report on a new species, Micryletta dissimulanssp. nov., from the lowland forests of southern Thailand, which is described based on molecular and morphological evidence. The new species is characterized by a combination of the following characters: small body size (20.3–22.4 mm in males, 24.4–26.7 mm in females); slender body habitus; head longer than wide; snout rounded in dorsal and lateral view; eye length equal to snout length; tibiotarsal articulation reaching to tympanum; dorsal surface slightly granulated to shagreened; supratympanic fold indistinct, ventrally edged in black with large black spot behind eye; outer metatarsal tubercle absent; dorsum reddish-brown with merging irregular-shaped brown blotches edged in beige, no black spots on dorsum; body flanks brown with large black spots edged in whitish mottling, two large black blotches in axillary and inguinal areas on each side; lateral sides of head black, with white patches on lips absent, whitish mottling on tympanum and axillary region; ventral surface pinkish to bluish-gray, translucent, laterally with dark-brown marbled pattern, medially immaculate; throat in males dark-gray with sparse white mottling laterally; iris copper-orange. The new species is divergent from all other congeners in 16S rRNA gene sequences (5.0%–7.4%). To date, Micryletta dissimulanssp. nov. is only known from a single locality in Saba Yoi District, Songkhla Province, Thailand, at an elevation of 120 m a.s.l., but is also expected to occur in neighboring parts of Malaysia. We suggest Micryletta dissimulanssp. nov. be considered as a Data Deficient (DD) species following the IUCN’s Red List categories (IUCN Standards and Petitions Committee, 2019).

Consequences of parallel miniaturisation in Microhylinae (Anura, Microhylidae), with the description of a new genus of diminutive South East Asian frogs

The genus Microhyla Tschudi, 1838 includes 52 species and is one of the most diverse genera of the family Microhylidae, being the most species-rich taxon of the Asian subfamily Microhylinae. The recent, rapid description of numerous new species of Microhyla with complex phylogenetic relationships has made the taxonomy of the group especially challenging. Several recent phylogenetic studies suggested paraphyly of Microhyla with respect to Glyphoglossus Günther, 1869, and revealed three major phylogenetic lineages of mid-Eocene origin within this assemblage. However, comprehensive works assessing morphological variation among and within these lineages are absent. In the present study we investigate the generic taxonomy of Microhyla–Glyphoglossus assemblage based on a new phylogeny including 57 species, comparative morphological analysis of skeletons from cleared-and-stained specimens for 23 species, and detailed descriptions of generalized osteology based on volume-rendered micro-CT scans for five species–altogether representing all major lineages within the group. The results confirm three highly divergent and well-supported clades that correspond with external and osteological morphological characteristics, as well as respective geographic distribution. Accordingly, acknowledging ancient divergence between these lineages and their significant morphological differentiation, we propose to consider these three lineages as distinct genera: Microhylasensu stricto, Glyphoglossus, and a newly described genus, Nanohylagen. nov.

A New Species of Micryletta (Amphibia: Anura) from Sumatra, Indonesia

Micryletta inornata is a complex species that is widely distributed from Sumatra to mainland Asia, including the Thai-Malay Peninsula and Indochina. Recently, this species was confirmed to be endemic to regions near the type locality in Sumatra, and the populations from other regions were suggested to be different species. We examined phenotypic and genotypic characters of the Sumatran populations and found an unnamed lineage in addition to the true M. inornata. The newly found lineage can be distinguished from M. inornata and other congeners by both molecular and morphological traits and has been named Micryletta sumatrana sp. nov. The new species is characterized by having a small body size, golden brown dorsum with scattered dark spots, dark brown ventrum with diffuse cream mottling, dark brown lateral head with cream spots on lips and the tympanum region extending to the axilla, and tibiotarsal articulation reaching to the front of the eye. We discuss the taxonomic status of so-called M. inornata occurring outside of its type locality, especially of M. inornata lineata.

A little frog leaps a long way: compounded colonizations of the Indian Subcontinent discovered in the tiny Oriental frog genus Microhyla (Amphibia: Microhylidae)

Frogs of the genus Microhyla include some of the world's smallest amphibians and represent the largest radiation of Asian microhylids, currently encompassing 50 species, distributed across the Oriental biogeographic region. The genus Microhyla remains one of the taxonomically most challenging groups of Asian frogs and was found to be paraphyletic with respect to large-sized fossorial Glyphoglossus. In this study we present a time-calibrated phylogeny for frogs in the genus Microhyla, and discuss taxonomy, historical biogeography, and morphological evolution of these frogs. Our updated phylogeny of the genus with nearly complete taxon sampling includes 48 nominal Microhyla species and several undescribed candidate species. Phylogenetic analyses of 3,207 bp of combined mtDNA and nuDNA data recovered three well-supported groups: the Glyphoglossus clade, Southeast Asian Microhyla II clade (includes M. annectens species group), and a diverse Microhyla I clade including all other species. Within the largest major clade of Microhyla are seven well-supported subclades that we identify as the M. achatina, M. fissipes, M. berdmorei, M. superciliaris, M. ornata, M. butleri, and M. palmipes species groups. The phylogenetic position of 12 poorly known Microhyla species is clarified for the first time. These phylogenetic results, along with molecular clock and ancestral area analyses, show the Microhyla-Glyphoglossus assemblage to have originated in Southeast Asia in the middle Eocene just after the first hypothesized land connections between the Indian Plate and the Asian mainland. While Glyphoglossus and Microhyla II remained within their ancestral ranges, Microhyla I expanded its distribution generally east to west, colonizing and diversifying through the Cenozoic. The Indian Subcontinent was colonized by members of five Microhyla species groups independently, starting with the end Oligocene-early Miocene that coincides with an onset of seasonally dry climates in South Asia. Body size evolution modeling suggests that four groups of Microhyla have independently achieved extreme miniaturization with adult body size below 15 mm. Three of the five smallest Microhyla species are obligate phytotelm-breeders and we argue that their peculiar reproductive biology may be a factor involved in miniaturization. Body size increases in Microhyla-Glyphoglossus seem to be associated with a burrowing adaptation to seasonally dry habitats. Species delimitation analyses suggest a vast underestimation of species richness and diversity in Microhyla and reveal 15-33 undescribed species. We revalidate M. nepenthicola, synonymize M. pulverata with M. marmorata, and provide insights on taxonomic statuses of a number of poorly known species. Further integrative studies, combining evidence from phylogeny, morphology, advertisement calls, and behavior will result in a better systematic understanding of this morphologically cryptic radiation of Asian frogs.

Climate Change and Edaphic Specialists: Irresistible Force Meets Immovable Object?

Species exposed to anthropogenic climate change can acclimate, adapt, move, or be extirpated. It is often assumed that movement will be the dominant response, with populations tracking their climate envelopes in space, but the numerous species restricted to specialized substrates cannot easily move. In warmer regions of the world, such edaphic specialists appear to have accumulated in situ over millions of years, persisting despite climate change by local movements, plastic responses, and genetic adaptation. However, past climates were usually cooler than today and rates of warming slower, while edaphic islands are now exposed to multiple additional threats, including mining. Modeling studies that ignore edaphic constraints on climate change responses may therefore give misleading results for a significant proportion of all taxa.

On the road to Mandalay: contribution to the Microhyla Tschudi, 1838 (Amphibia: Anura: Microhylidae) fauna of Myanmar with description of two new species

We present a morphological and molecular assessment of the Microhyla fauna of Myanmar based on new collections from central (Magway Division) and northern (Kachin State) parts of the country. In total, six species of Microhyla are documented, including M. berdmorei, M. heymonsi, M. butleri, M. mukhlesuri and two new species described from the semi-arid savanna-like plains of the middle part of the Irrawaddy (Ayeyarwady) River Valley. We used a 2 481 bp long 12S rRNA-16S rRNA fragment of mtDNA to hypothesize genealogical relationships within Microhyla. We applied an integrative taxonomic approach combining molecular, morphological, and acoustic lines of evidence to evaluate the taxonomic status of Myanmar Microhyla. We demonstrated that the newly discovered populations of Microhyla sp. from the Magway Division represent two yet undescribed species. These two new sympatric species are assigned to the M. achatina species group, with both adapted to the seasonally dry environments of the Irrawaddy Valley. Microhyla fodiens sp. nov. is a stout-bodied species with a remarkably enlarged shovel-like outer metatarsal tubercle used for burrowing and is highly divergent from other known congeners (P-distance≥8.8%). Microhyla irrawaddy sp. nov. is a small-bodied slender frog reconstructed as a sister species to M. kodial from southern India (P-distance=5.3%); however, it clearly differs from the latter both in external morphology and advertisement call parameters. Microhyla mukhlesuri is reported from Myanmar for the first time. We further discuss the morphological diagnostics and biogeography of Microhyla species recorded in Myanmar.

A new species of Micryletta frog (Microhylidae) from Northeast India

We describe a new species of frog in the microhylid genus Micryletta Dubois, 1987 from Northeast India based on molecular and morphological evidence. The new species, formally described as Micryletta aishani sp. nov., is phenotypically distinct from other congeners by a suite of morphological characters such as brown to reddish-brown dorsum; dorsal skin shagreened with minute spinules; snout shape nearly truncate in dorsal and ventral view; a prominent dark streak extending from tip of the snout up to the lower abdomen; ash-grey mottling along the margins of upper and lower lip extending up to the flanks, limb margins and dorsal surfaces of hand and foot; tibiotarsal articulation reaching up to the level of armpits; absence of outer metatarsal tubercles; and absence of webbing between toes. Phylogenetic relationships within the genus are inferred based on mitochondrial data and the new taxon is found to differ from all the recognised Micryletta species by 3.5-5.9% divergence in the mitochondrial 16S rRNA. The new species was found in the states of Assam, Manipur, and Tripura, from low to moderate elevation (30-800 m asl) regions lying south of River Brahmaputra and encompassing the Indo-Burma Biodiversity Hotspot. The discovery validates the presence of genus Micryletta in Northeast India based on genetic evidence, consequently confirming the extension of its geographical range, westwards from Southeast Asia up to Northeast India. Further, for nomenclatural stability of two previously known species, Microhyla inornata (= Micryletta inornata) and Microhyla steinegeri (= Micryletta steinegeri), lectotypes are designated along with detailed descriptions.