Impact of the Mid-Pleistocene Revolution and Anthropogenic Factors on the Dispersion of Asian Black-Spined Toads (Duttaphrynus melanostictus)

Integrating wing morphometrics and mitochondrial DNA analysis to assess the filaria vector Mansonia uniformis (Diptera: Culicidae) populations in Thailand

Mansonia uniformis (Diptera: Culicidae) is recognized as a vector of Brugia malayi and has been reported to transmit Wuchereria bancrofti, both causing lymphatic filariasis in humans. This study employed geometric morphometrics (GM) to investigate wing shape variation and analyzed genetic diversity through cytochrome c oxidase subunit 1 (COI) gene analyses in Ma. uniformis populations across Thailand. Wing GM analyses indicated significant differences in wing shape based on Mahalanobis distances among nearly all population pairs (p < 0.05), with no significant correlation between wing shape and geographic distance (r = 0.210, p > 0.05). Genetic analyses identified 63 haplotypes and 49 polymorphic sites, with the overall population exhibiting a nucleotide diversity of 0.006 (± 0.001) and a haplotype diversity of 0.912 (± 0.017). Deviations from neutrality, as indicated by Tajima's D and Fu's FS tests for the overall Ma. uniformis populations in Thailand, were statistically significant and negative, suggesting population expansion (both p < 0.05). Analysis of molecular variance revealed no significant genetic structure when all populations were categorized based on collection sites and geographic regions. However, significant differences in FST values were observed between some populations. These findings enhance our understanding of the geographical and genetic factors influencing Ma. uniformis populations, which are crucial for developing effective control strategies in Thailand.

On the edge of the Shivaliks: An insight into the origin and taxonomic position of Pakistani toads from the Duttaphrynus melanostictus complex (Amphibia, Bufonidae)

The common Asian toad Duttaphrynus melanostictus (Schneider, 1799) complex has a wide distribution ranging from western foothills of the Himalaya to the easternmost range of the Wallacea, with the evidence of human-mediated introductions to some other areas. In the entire distribution range, the complex is formed by several evolutionary clades, distributed mostly in South-East Asia with unresolved taxonomy. In the northwestern edge of its distribution (Pakistan), the name D. melanostictus hazarensis (Khan, 2001) has been assigned to local populations but its biological basis remained, so far, understudied and unvalidated. Therefore, we re-evaluated the available genetic data (mitochondrial and nuclear) to show the relationships between Pakistani populations (including the type locality of D. m. hazarensis) and others from across the range. Our results showed that Pakistani populations are associated with one, deeply diverged, well-supported and widely distributed clade (so-called Duttaphrynus sp. 1 according to 16S, or clade B based on tRNAGly-ND3), that has already been detected in previous studies. This clade is further distributed in India, Nepal, Bangladesh, Malaysia, Singapore, and Indonesia and is characterized by a low level of genetic variability. This further suggests that both natural, as well as potential human-mediated dispersal, might have played an important role in setting up the current phylogeographic and distribution pattern of this clade. The clade is deeply divergent from other clades of the complex and represents a taxonomically unresolved entity. We here argue that the clade Duttaphrynus sp. 1/B represents a distinct species for which the name Duttaphrynus bengalensis (Daudin, 1802) comb. nov. is applicable, while the description of D. m. hazarensis does not satisfy the rules of the International Code of Zoological Nomenclature.

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.

From Gondwana to the Yellow Sea, evolutionary diversifications of true toads Bufo sp. in the Eastern Palearctic and a revisit of species boundaries for Asian lineages

Taxa with vast distribution ranges often display unresolved phylogeographic structures and unclear taxonomic boundaries resulting in hidden diversity. This hypothesis-driven study reveals the evolutionary history of Bufonidae, covering the phylogeographic patterns found in Holarctic bufonids from the West Gondwana to the phylogenetic taxonomy of Asiatic true toads in the Eastern Palearctic. We used an integrative approach relying on fossilized birth-death calibrations, population dynamics, gene-flow, species distribution, and species delimitation modeling to resolve the biogeography of the clade and highlight cryptic lineages. We verified the near-simultaneous Miocene radiations within Western and Eastern Palearctic Bufo, c. 14.49-10.00 Mya, temporally matching with the maximum dust outflows in Central Asian deserts. Contrary to earlier studies, we demonstrated that the combined impacts of long dispersal and ice-age refugia equally contributed to the current genetic structure of Bufo in East Asia. Our findings reveal a climate-driven adaptation in septentrional Eastern Asian Bufo, explaining its range shifts toward northern latitudes. We resolve species boundaries within the Eastern Palearctic Bufo, and redefine the taxonomic and conservation units of the northeastern species: B. sachalinensis and its subspecies.

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.

Impact of the Miocene orogenesis on Kaloula spp. radiation and implication of local refugia on genetic diversification

The phylogeography of the Kaloula genus in East Asia is still poorly understood. One of the difficulties is the absence of fossils to corroborate molecular dating estimates. Here, we examined the mitochondrial structure of Kaloula spp. in East Asia and focused on the impact of glaciations on the northernmost species: Kaloula borealis. We determined the phylogenetic relationships, molecular dating, and genetic connectivity assessments within the genus from 1211 bp of concatenated mitochondrial 12S and 16S. The relaxed clock analyses reveal the emergence of Kaloula spp. common ancestor in East and Southeast Asia between the Eocene and Oligocene, c. 38.47 Ma (24.69-53.65). The genetic diversification of lineages then increased on the East Asian Mainland during the Lower Miocene, c. 20.10 (8.73-30.65), most likely originating from the vicariance and radiation triggered by the orogeny of the Qinghai-Tibetan Plateau. Later, the dispersal towards the North East Asian Mainland during the Upper Miocene drove the population diversification of K. borealis c. 9.01 Ma (3.66-15.29). Finally, the central mainland population became isolated following orogenesis events and diverged into K. rugifera during the Pliocene, c. 3.06 Ma (0.02-10.90). The combination of population genetic and barrier analyses revealed a significant genetic isolation between populations of Kaloula spp. matching with the massive Qinling-Daba Mountain chain located in south-central China. Finally, we highlight a young divergence within the Eastern Mainland population of K. borealis, possibly attributed to refugia in south eastern China from which populations later expanded.