A new species of Kurixalus (Anura: Rhacophoridae) from northern Vietnam with comments on the biogeography of the genus

First description of the female and morphological variations with range extension of Kurixaluslenquanensis (Anura, Rhacophoridae)

Background

Kurixaluslenquanensis Yu, Wang, Hou, Rao and Yang, 2017 was originally described, based on 14 adult male specimens from Lengquan Village, Mengzi, Yunnan, China. So far, this species is known only from south-eastern Yunnan and information on females of this species is not available. During the field surveys in 2023, two Kurixalus specimens (one female and one male) were collected from central eastern Yunnan (Shilin, Kunming, Yunnan, China). These two specimens were confirmed to be K.lenquanensis by molecular phylogenetic analyses, based on 16S rRNA sequences.

New information

A female specimen of K.lenquanensis is described for the first time and morphological variation amongst populations of this species is provided. The diagnosis and distribution of this species are updated.

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 I1¼-1¼II1-2III1-1IV, toe webbing formula I½-½II0-1½III¼-1¾IV1¾-½V. 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.

Description of a new Kurixalus species (Rhacophoridae, Anura) and a northwards range extension of the genus

Knowledge of biodiversity before species become extinct is paramount to conservation, especially when the relevant species are far from their expected distribution and, thus, likely overlooked. Here, we describe a new Kurixalus species corresponding to a range extension of Kurixalus on the Asian mainland, with the closest population in Taiwan. The species diverged from its closest relative during the Late Pliocene to Pleistocene, ca. 3.06 Mya (HPD 95%: 5.82-0.01), based on calibrations with a relaxed clock species tree of unlinked mtDNA 12S rRNA and nuclear DNA TYR. The status of the newly-described species is also supported by a divergence in call properties and morphometrics. We named the species described here as Kurixalusinexpectatus sp. nov. due to the nature of the discovery, as well as the adjunct distribution of the species relative to its closest congeners. The species was found in Zhejiang Province and it represents a range extension of 663 km for the Kurixalus genus.

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.

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.

First national record of Quasipaaverrucospinosa (Bourret, 1937) (Amphibia: Anura: Dicroglossidae) from Thailand with further comment on its taxonomic status

Background

Spiny Frog Quasipaa is a genus of frogs that belongs to a relatively poorly known group. Most of the species distribution has been recorded in China; however, a few incidences of identification have occurred in the eastern part of Indochina. To date, only one species (Quasipaafasciculispina) of Quasipaa has been recorded from Chanthaburi and Trat Provinces in south-eastern Thailand.

New information

Based on recent fieldwork conducted in northern Thailand, we report a new record of Quasipaaverrucospinosa from Doi Phu Kha National Park, Nan Province at an altitude of 900–1000 m a.s.l. Our study has demonstrated that populations of this species are paraphyletic and has revealed deep genetic differences. Therefore, it is recommended that a comprehensive study be undertaken to clarify the taxonomic and geographic distribution of this species for its suitable protection and conservation.

First national record of Gracixalus quangi Rowley, Dau, Nguyen, Cao & Nguyen, 2011 and G. yunnanensis Yu, Li, Wang, Rao, Wu &Yang, 2019 (Amphibia: Anura: Rhacophoridae) from Thailand

Background

The bushfrog genus Gracixalus Delorme, Dubois, Grosjean & Ohler, 2005 is found in southern and south-western China, Vietnam, Laos, Thailand and Myanmar. It is presently comprised of 17 species. In Thailand, only two species have been recorded, namely G.carinensis (Boulenger) and G.seesom (Massui, Khonsue, Panha & Eto). The latter of these two species is currently known to be endemic to the country.

New information

Based on recent field work conducted in 2019 in Doi Phu Kha National Park, Nan Province of northern Thailand, we are reporting two new records of the genus Gracixalus, G.quangi and G.yunnanensis, from Thailand, based on morphological and molecular evidence. In addition, this is the first study to report on the identification of a female specimen of G.yunnanensis. Furthermore, morphological data and natural history notes of the aforementioned species in Thailand have been provided, along with updated locations for the distribution of both species.

First Detection of Batrachochytrium dendrobatidis in Wild Frogs from Bangladesh

Global amphibian populations are facing a novel threat, chytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis (Bd), which is responsible for the severe decline of a number of species across several continents. Chytridiomycosis in Asia is a relatively recent discovery yet there have been no reports on Bd-presence in Bangladeshi amphibians. We conducted a preliminary study on 133 wild frogs from seven sites in Bangladesh between April and July 2018. Nested PCR analysis showed 20 samples (15.04%) and 50% of the tested taxa (9 species from 6 genera and 4 families) as Bd-positive. Eight of the nine species are discovered as newly infected hosts. Analysis of Bd-positive samples shows prevalence does not significantly vary among different land cover categories, although the occurrence is higher in forested areas. The prevalence rate is similar in high and low disturbed areas, but the range of occurrence is statistically higher in low disturbance areas. Maximum entropy distribution modeling indicates high probabilities of Bd occurrence in hilly and forested areas in southeast and central-north Bangladesh. The Bd-specific ITS1-5.8S-ITS2 ribosomal gene sequence from the Bd-positive samples tested is completely identical. A neighbor-joining phylogenetic tree reveals that the identified strain shares a common ancestry with strains previously discovered in different Asian regions. Our results provide the first evidence of Bd-presence in Bangladeshi amphibians, inferring that diversity is at risk. The effects of environmental and climatic factors along with quantitative PCR analysis are required to determine the infection intensity and susceptibility of amphibians in the country.

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 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.