Comprehensive multi-locus phylogeny of Old World tree frogs (Anura: Rhacophoridae) reveals taxonomic uncertainties and potential cases of over- and underestimation of species diversity

Morphological and genetic analysis of Sulawesi Rhacophorus and description of a fourth species endemic to the island

A new species of tree frog of the genus Rhacophorus is described from two different localities on Sulawesi Island, Indonesia. The new species is divergent morphologically and genetically, and is deeply nested within the monophyletic group of endemic Sulawesian Rhacophorus comprising R. edentulus, R. georgii, and R. monticola. The new species has a combination of distinctive morphological characteristics that distinguishes it from other Rhacophorus species, including from other Sulawesian Rhacophorus: medium size SVL 40.4-44.6 mm in males; 48.1-54.2 mm in females, males have sloped snout in lateral view, presence of vomerine teeth, absence of a bony crest in the occipital region of the skull, dorsal skin coarsely granular with white-tipped keratinized asperities, flank with white blotched pattern, dermal flaps absent on limbs, heel without dermal appendage, and tuberculate cloaca. The discovery of the new species enhances knowledge of the diversity of endemic Sulawesian amphibians and requires future conservation efforts, especially in light of ongoing threats such as agricultural expansion.

A multi-gene phylogeny of the Asian kukri snakes (Oligodon Fitzinger, 1826): Sharpening the blade of the second largest serpent radiation (Reptilia: Squamata: Colubridae)

With 90 recognized species, kukri snakes in the genus Oligodon Fitzinger constitute the second largest snake radiation in the world. Oligodon species are collectively distributed across the Asian continent and possess several ecological and morphological attributes that are unique amongst other snakes. Despite their high levels of species richness, evolutionary relationships within Oligodon are poorly understood due to a limited number of samples and genetic markers available in earlier phylogenies. In this study, we assembled the largest molecular dataset of Oligodon to date, which we use to assess the systematics and biogeography of the entire genus. Based on a combination of maximum likelihood and Bayesian phylogenies using fragments of three mitochondrial genes (12 s, 16 s, CytB) and three nuclear genes (Rag1, C-mos, BDNF), we identify eight deeply divergent clades within Oligodon, of which only two correspond with species groupings that were recognized by previous morphological classifications. Four species delimitation methods employed on the mitochondrial portion of the dataset resulted in dramatically divergent estimations of molecular operational taxonomic units (mOTUs). When combined, all four methods support the existence of unrecognized species-level lineages, but also indicate that several other Oligodon species are poorly differentiated genetically and require additional integrative taxonomic research to properly resolve. Based on divergence dating, we demonstrate that Oligodon began to diversify during the early Neogene and hypothesize that the most recent common ancestor of the genus originated in mainland Southeast Asia. We conclude by recognizing eight phylogenetically defined species groups and identify sampling gaps that require further investigation once new data becomes available. This study contributes to a greater understanding of snake evolution on the Asian continent and acts as a baseline for future studies of this speciose genus.

A new species of Raorchestes (Anura, Rhacophoridae) from Yunnan Province, China

A new bush frog species is described from Yunnan, China, based on phylogenetic analyses, species delimitation analyses, and morphological comparisons. Raorchesteshekouensissp. nov. is distinguished from all other congeners by a combination of 11 morphological characters. The new species brings the current number of Raorchestes species in China to ten, nine of which are distributed in Yunnan. Molecular analyses supported an unnamed lineage previously recorded as "Raorchestesgryllus" in northern Vietnam. Further studies including additional samples are necessary to clarify the species diversity and boundaries of Raorchestes in China and Indochina.

Integrated phylogenetic analyses reveal the evolutionary, biogeographic, and diversification history of Asian warty treefrog genus Theloderma (Anura, Rhacophoridae)

Asian warty treefrogs, genus Theloderma, are morphologically variable arboreal frogs endemic to Southeast Asia and Southern China. However, integrated systematic studies are lacking, and knowledge of the genus in terms of diversity, origin, and historical diversification remains limited. To address these knowledge gaps, we used three mitochondrial and five nuclear gene fragments to reconstruct the Theloderma phylogeny, estimate divergence times, and examine the biogeography of the genus. Phylogenetic and species delimitation analyses suggest that the genus Theloderma comprises three major clades corresponding to two subgenera and seven species groups, and mPTP identified at least 12 putative cryptic species, suggesting that species diversity has been underestimated. Biogeographic analyses indicated that most recent common ancestor of Theloderma originated in the Indochina Peninsula during the Middle Oligocene (ca. 27.77 Ma) and the splitting of Clade A to C occurred in the Late Oligocene (ca. 23.55-25.57 Ma). Current biogeographic patterns result from two distinct processes: in situ diversification in the Indochina Peninsula and dispersal in multiple areas, namely southward dispersal to the Malay Peninsula and Borneo, northeastward dispersal to Southern China, northward dispersal to the Himalayas, and dispersal from Southern China to the Indochina Peninsula. Ancestral character reconstruction suggests that the ancestor of Theloderma may have possessed a small body size, rough dorsal skin, and absence of vomerine teeth and hand webbing, and that these four characters have undergone multiple evolutions. Principal component analysis based on eight bioclimatic variables did not clearly distinguish the three major clades of Theloderma, suggesting that species in these clades may occupy similar climatic ecological niches. Our research highlights the importance of orogeny and paleoclimatic changes, in shaping amphibian biodiversity in mountain ecosystems.

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.

A new species of Bush frog (Anura, Rhacophoridae, Raorchestes) from southeastern Yunnan, China

In this study, based on morphological and molecular data, a new bush frog species is described from Yunnan, China. Eleven samples of Raorchestes malipoensissp. nov. were collected from Malipo County, southeastern Yunnan. This species can be distinguished from other congeners by a combination of 13 morphological characters. Phylogenetic analyses based on the 16S rRNA gene indicate that these individuals form a monophyletic group, and genetic divergence between this clade and its closest relatives is higher than 3.1%, which is comparable to the divergence between recognized Raorchestes species. The discovery of this new species suggests that additional extensive surveys in the southeastern Yunnan would yield more amphibian lineages yet unknown to science.

A new species of Rhacophorus (Anura, Rhacophoridae) from Guangxi, China

Based on morphological and molecular evidence of five male adult specimens collected from Napo County, Baise City, Guangxi Zhuang Autonomous Region, China, we describe a new species of Rhacophorus, Rhacophorusnapoensis sp. nov. This new species is similar to Rhacophorusrhodopus Liu & Hu, 1959 and Rhacophorusbipunctatus Ahl, 1927 in morphology, but it can be distinguished from the latter two by the following morphological characteristics: head width is greater than head length, snout pointed, loreal region oblique, tympanum distinct, maxillary teeth distinct, tongue cordiform, external single subgular vocal sac, tibiotarsal articulation reaches the snout, tibia length is greater than foot length and slightly greater than half of snout-vent length, and single outer metatarsal tubercle is flat. The phylogenetic tree constructed based on 16S rRNA sequence shows that all individuals of this species clustered into the same clade, and genetically this new species differs from R.rhodopus and R.bipunctatus by 7.71% and 7.98% in 16S rRNA sequences, respectively.

The mitochondrial genome and phylogenetic analysis of Rhacophorus rhodopus

Classification of the genus Rhacophorus has been problematic. In particular there has been considerable controversy surrounding the phylogenetic relationships among Rhacophorus rhodopus, R. bipunctatus, and R. reinwardtii. To examine the relationship among these Rhacophorus species, we assembled the complete mitochondrial genome sequence of R. rhodopus. The R. rhodopus genome is 15,789 bp in length with 12 protein-coding genes (PCGs) (losing ND5), two ribosomal genes, 22 transfer RNA genes, and a control region (D-loop). Base composition of the overall sequence was 60.86% for A + T content and 39.14% for C + G content. Most of the PCGs used ATG as a start codon, except for the COX I gene, which used the ATA start codon. COX I and ND6 used AGG and ATP8 stop codons respectively, while ND3 and ND4L used the TAA stop codon. For the remaining seven genes, the stop codons was incomplete. In addition, both 5' and 3' of the control areas had distinct repeating regions. Based on three datasets and two methods (Bayesian inference (BI) and maximum likelihood (ML)), we reconstructed three phylogenetic trees to explore the taxonomic status of the species and the phylogenetic relationship among R. rhodopus, R. bipunctatus and R. reinwardtii. Our results indicated that these three species are non-monophyletic; thus, the phylogenetic relationship among them is complex and difficult to determine. Further, R. rhodopus is divided into three lineages from different parts of China. The two Rhacophorus samples showed very close phylogenetic relationship with R. rhodopus. Our results add to the mitochondrial genome database of amphibians and will help to disentangle the phylogenetic relationships within the Rhacophoridae.

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.

Molecular species delimitation of shrub frogs of the genus Pseudophilautus (Anura, Rhacophoridae)

Sri Lanka is an amphibian hotspot of global significance. Its anuran fauna is dominated by the shrub frogs of the genus Pseudophilautus. Except for one small clade of four species in Peninsular India, these cool-wet adapted frogs, numbering some 59 extant species, are distributed mainly across the montane and lowland rain forests of the island. With species described primarily by morphological means, the diversification has never yet been subjected to a molecular species delimitation analysis, a procedure now routinely applied in taxonomy. Here we test the species boundaries of Pseudophilautus in the context of the phylogenetic species concept (PSC). We use all the putative species for which credible molecular data are available (nDNA-Rag-1; mt-DNA- 12S rRNA, 16S rRNA) to build a well resolved phylogeny, which is subjected to species delimitation analyses. The ABGD, bPTP, mPTP and bGMYC species delimitation methods applied to the 16S rRNA frog barcoding gene (for all species), 12S rRNA and Rag-1 nDNA grouped P. procax and P. abundus; P. hallidayi and P. fergusonianus; P. reticulatus and P. pappilosus; P. pleurotaenia and P. hoipolloi; P. hoffmani and P. asankai; P. silvaticus and P. limbus; P. dilmah and P. hankeni; P. fulvus and P. silus.. Surprisingly, all analyses recovered 14 unidentified potential new species as well. The geophylogeny affirms a distribution across the island's aseasonal 'wet zone' and its three principal hill ranges, suggestive of allopatric speciation playing a dominant role, especially between mountain masses. Among the species that are merged by the delimitation analyses, a pattern leading towards a model of parapatric speciation emerges-ongoing speciation in the presence of gene flow. This delimitation analysis reinforces the species hypotheses, paving the way to a reasonable understanding of Sri Lankan Pseudophilautus, enabling both deeper analyses and conservation efforts of this remarkable diversification. http://zoobank.org/urn:lsid:zoobank.org:pub:DA869B6B-870A-4ED3-BF5D-5AA3F69DDD27.

Unexpectedly high levels of lineage diversity in Sundaland puddle frogs (Dicroglossidae: Occidozyga Kuhl and van Hasselt, 1822)

One of the most urgent contemporary tasks for taxonomists and evolutionary biologists is to estimate the number of species on earth. Recording alpha diversity is crucial for protecting biodiversity, especially in areas of elevated species richness, which coincide geographically with increased anthropogenic environmental pressures - the world's so-called biodiversity hotspots. Although the distribution of Puddle frogs of the genus Occidozyga in South and Southeast Asia includes five biodiversity hotspots, the available data on phylogeny, species diversity, and biogeography are surprisingly patchy. Samples analyzed in this study were collected throughout Southeast Asia, with a primary focus on Sundaland and the Philippines. A mitochondrial gene region comprising ~ 2000 bp of 12S and 16S rRNA with intervening tRNA Valine and three nuclear loci (BDNF, NTF3, POMC) were analyzed to obtain a robust, time-calibrated phylogenetic hypothesis. We found a surprisingly high level of genetic diversity within Occidozyga, based on uncorrected p-distance values corroborated by species delimitation analyses. This extensive genetic diversity revealed 29 evolutionary lineages, defined by the > 5% uncorrected p-distance criterion for the 16S rRNA gene, suggesting that species diversity in this clade of phenotypically homogeneous forms probably has been underestimated. The comparison with results of other anuran groups leads to the assumption that anuran species diversity could still be substantially underestimated in Southeast Asia in general. Many genetically divergent lineages of frogs are phenotypically similar, indicating a tendency towards extensive morphological conservatism. We present a biogeographic reconstruction of the colonization of Sundaland and nearby islands which, together with our temporal framework, suggests that lineage diversification centered on the landmasses of the northern Sunda Shelf. This remarkably genetically structured group of amphibians could represent an exceptional case for future studies of geographical structure and diversification in a widespread anuran clade spanning some of the most pronounced geographical barriers on the planet (e.g., Wallace's Line). Studies considering gene flow, morphology, ecological and bioacoustic data are needed to answer these questions and to test whether observed diversity of Puddle frog lineages warrants taxonomic recognition.

Gene Flow Increases Phylogenetic Structure and Inflates Cryptic Species Estimations: A Case Study on Widespread Philippine Puddle Frogs (Occidozyga laevis)

In cryptic amphibian complexes, there is a growing trend to equate high levels of genetic structure with hidden cryptic species diversity. Typically, phylogenetic structure and distance-based approaches are used to demonstrate the distinctness of clades and justify the recognition of new cryptic species. However, this approach does not account for gene flow, spatial, and environmental processes that can obfuscate phylogenetic inference and bias species delimitation. As a case study, we sequenced genome-wide exons and introns to evince the processes that underlie the diversification of Philippine Puddle Frogs-a group that is widespread, phenotypically conserved, and exhibits high levels of geographically-based genetic structure. We showed that widely adopted tree- and distance-based approaches inferred up to 20 species, compared to genomic analyses that inferred an optimal number of five distinct genetic groups. Using a suite of clustering, admixture, and phylogenetic network analyses, we demonstrate extensive admixture among the five groups and elucidate two specific ways in which gene flow can cause overestimations of species diversity: (1) admixed populations can be inferred as distinct lineages characterized by long branches in phylograms; and (2) admixed lineages can appear to be genetically divergent, even from their parental populations when simple measures of genetic distance are used. We demonstrate that the relationship between mitochondrial and genome-wide nuclear p-distances is decoupled in admixed clades, leading to erroneous estimates of genetic distances and, consequently, species diversity. Additionally, genetic distance was also biased by spatial and environmental processes. Overall, we showed that high levels of genetic diversity in Philippine Puddle Frogs predominantly comprise metapopulation lineages that arose through complex patterns of admixture, isolation-by-distance, and isolation-by-environment as opposed to species divergence. Our findings suggest that speciation may not be the major process underlying the high levels of hidden diversity observed in many taxonomic groups and that widely-adopted tree- and distance-based methods overestimate species diversity in the presence of gene flow.

An integrative approach to infer systematic relationships and define species groups in the shrub frog genus Raorchestes, with description of five new species from the Western Ghats, India

The genus Raorchestes is a large radiation of Old World tree frogs for which the Western Ghats in Peninsular India is the major center for origin and diversification. Extensive studies on this group during the past two decades have resolved long-standing taxonomic confusions and uncovered several new species, resulting in a four-fold increase in the number of known Raorchestes frogs from this region. Our ongoing research has revealed another five new species in the genus, formally described as Raorchestes drutaahu sp. nov., Raorchestes kakkayamensis sp. nov., Raorchestes keirasabinae sp. nov., Raorchestes sanjappai sp. nov., and Raorchestes vellikkannan sp. nov., all from the State of Kerala in southern Western Ghats. Based on new collections, we also provide insights on the taxonomic identity of three previously known taxa. Furthermore, since attempts for an up-to-date comprehensive study of this taxonomically challenging genus using multiple integrative taxonomic approaches have been lacking, here we review the systematic affinities of all known Raorchestes species and define 16 species groups based on evidence from multi-gene (2,327 bp) phylogenetic analyses, several morphological characters (including eye colouration and pattern), and acoustic parameters (temporal and spectral properties, as well as calling height). The results of our study present novel insights to facilitate a better working taxonomy for this rather speciose and morphologically conserved radiation of shrub frogs. This will further enable proper field identification, provide momentum for multi-disciplinary studies, as well as assist conservation of one of the most colourful and acoustically diverse frog groups of the Western Ghats biodiversity hotspot.

Target-capture phylogenomics provide insights on gene and species tree discordances in Old World treefrogs (Anura: Rhacophoridae)

Genome-scale data have greatly facilitated the resolution of recalcitrant nodes that Sanger-based datasets have been unable to resolve. However, phylogenomic studies continue to use traditional methods such as bootstrapping to estimate branch support; and high bootstrap values are still interpreted as providing strong support for the correct topology. Furthermore, relatively little attention has been given to assessing discordances between gene and species trees, and the underlying processes that produce phylogenetic conflict. We generated novel genomic datasets to characterize and determine the causes of discordance in Old World treefrogs (Family: Rhacophoridae)-a group that is fraught with conflicting and poorly supported topologies among major clades. Additionally, a suite of data filtering strategies and analytical methods were applied to assess their impact on phylogenetic inference. We showed that incomplete lineage sorting was detected at all nodes that exhibited high levels of discordance. Those nodes were also associated with extremely short internal branches. We also clearly demonstrate that bootstrap values do not reflect uncertainty or confidence for the correct topology and, hence, should not be used as a measure of branch support in phylogenomic datasets. Overall, we showed that phylogenetic discordances in Old World treefrogs resulted from incomplete lineage sorting and that species tree inference can be improved using a multi-faceted, total-evidence approach, which uses the most amount of data and considers results from different analytical methods and datasets.

Gene flow creates a mirage of cryptic species in a Southeast Asian spotted stream frog complex

Most new cryptic species are described using conventional tree- and distance-based species delimitation methods (SDMs), which rely on phylogenetic arrangements and measures of genetic divergence. However, although numerous factors such as population structure and gene flow are known to confound phylogenetic inference and species delimitation, the influence of these processes is not frequently evaluated. Using large numbers of exons, introns, and ultraconserved elements obtained using the FrogCap sequence-capture protocol, we compared conventional SDMs with more robust genomic analyses that assess population structure and gene flow to characterize species boundaries in a Southeast Asian frog complex (Pulchrana picturata). Our results showed that gene flow and introgression can produce phylogenetic patterns and levels of divergence that resemble distinct species (up to 10% divergence in mitochondrial DNA). Hybrid populations were inferred as independent (singleton) clades that were highly divergent from adjacent populations (7%-10%) and unusually similar (<3%) to allopatric populations. Such anomalous patterns are not uncommon in Southeast Asian amphibians, which brings into question whether the high levels of cryptic diversity observed in other amphibian groups reflect distinct cryptic species-or, instead, highly admixed and structured metapopulation lineages. Our results also provide an alternative explanation to the conundrum of divergent (sometimes nonsister) sympatric lineages-a pattern that has been celebrated as indicative of true cryptic speciation. Based on these findings, we recommend that species delimitation of continuously distributed "cryptic" groups should not rely solely on conventional SDMs, but should necessarily examine population structure and gene flow to avoid taxonomic inflation.

DNA-based species delimitation reveals cryptic and incipient species in synchronous flashing fireflies (Coleoptera: Lampyridae) of Southeast Asia

Synchronous flashing fireflies of the genus Pteroptyx are ubiquitous throughout Southeast Asia, yet fundamental knowledge about their biodiversity is lacking. Recent studies have revealed notable population-level phylogeographical structure within the Pteroptyx tener and P. bearni groups in Malaysia, suggesting that cryptic species may exist. Additionally, morphological and genetic similarities between P. balingiana and P. malaccae have raised questions about the former’s validity as a distinct species. We collected samples from previously unsampled populations and assembled the most comprehensive genetic dataset for Pteroptyx to date, to characterize species boundaries within the P. tener, P. bearni and P. malaccae groups. Using a suite of species delimitation analyses, we show that P. tener along the west coast of Peninsular Malaysia (PM) is distinct from populations from the east coast and Borneo despite the absence of morphological differentiation. However, analyses could not conclusively differentiate P. bearni from Borneo and eastern PM, nor identify P. balingiana and P. malaccae as distinct species, indicating that these populations may be conspecific or represent incipient species. This study underlines the need to increase geographical, taxonomic and genetic sampling of Southeast Asian fireflies to provide a better understanding of their biodiversity.

Just the once will not hurt: DNA suggests species lumping over two oceans in deep-sea snails (Cryptogemma)

The practice of species delimitation using molecular data commonly leads to the revealing of species complexes and an increase in the number of delimited species. In a few instances, however, DNA-based taxonomy has led to lumping together of previously described species. Here, we delimit species in the genus Cryptogemma (Gastropoda: Conoidea: Turridae), a group of deep-sea snails with a wide geographical distribution, primarily by using the mitochondrial COI gene. Three approaches of species delimitation (ABGD, mPTP and GMYC) were applied to define species partitions. All approaches resulted in eight species. According to previous taxonomic studies and shell morphology, 23 available names potentially apply to the eight Cryptogemma species that were recognized herein. Shell morphometrics, radular characters and geographical and bathymetric distributions were used to link type specimens to these delimited species. In all, 23 of these available names are here attributed to seven species, resulting in 16 synonymizations, and one species is described as new: Cryptogemma powelli sp. nov. We discuss the possible reasons underlying the apparent overdescription of species within Cryptogemma, which is shown here to constitute a rare case of DNA-based species lumping in the hyper-diversified superfamily Conoidea.

An integrative phylogenomic approach illuminates the evolutionary history of Old World tree frogs (Anura: Rhacophoridae)

Rhacophoridae are one of the most speciose and ecologically diverse families of amphibians. Resolution of their evolutionary relationships is key to understanding the accumulation of biodiversity, yet previous hypotheses based on Sanger sequencing exhibit much discordance amongst generic relationships. This conflict precludes the making of sound macroevolutionary conclusions. Herein, we conduct the first phylogenomic study using broad-scale sampling and sequences of 352 nuclear DNA loci obtained using anchored hybrid enrichment targeted sequencing. The robust time-calibrated phylogenetic hypothesis clarifies several long-disputed relationships and facilitates the testing of evolutionary hypotheses on spatiotemporal diversification and reproductive modes. The major extant lineages of Rhacophoridae appear to have radiated in mainland Asia, and the spatiotemporal process corresponds with several common accumulations of biodiversity in Asia. Analyses do not detect any case of "Out of Himalaya" in Rhacophoridae. All transitions of reproductive modes appear to have evolved in an ordered, gradual sequence associated with gaining independence of standing water for larval development. The different reproductive modes are phylogenetically conserved and the completion of their transitions appear to have occurred over a period of ~30 Ma, which does not fit a pattern of a rapid burst of diversification. Innovations in reproductive modes associate statistically with the uneven distribution of species-richness between clades, where higher diversification is linked to increased terrestrial modes of reproduction. These results strengthen the hypothesis that breeding innovations drive diversification by providing new opportunities for ecological release and dispersion.

A new species of the genus Xenophrys Anura Megophryidae from northern Thailand

Species of Xenophrys are conserved morphologically and live primarily in forests. In Thailand, the genus harbors many cryptic species. Herein we report the collection of specimens from Doi Inthanon, Chiang Mai Province, northern Thailand, which were identified previously as X. minor. Molecular and morphological analyses find that these specimens differ significantly from other known congeners, and therefore we describe a new species. Further, our phylogenetic analyses indicate that X. latidactyla is a junior synonym of X. palpebralespinosa.

To split or not to split? Multilocus phylogeny and molecular species delimitation of southeast Asian toads (family: Bufonidae)

BACKGROUND

Recent studies have demonstrated that Bayesian species delimitation based on the multispecies coalescent model can produce inaccurate results by misinterpreting population splits as species divergences. An approach based on the genealogical divergence index (gdi) was shown to be a viable alternative, especially for delimiting allopatric populations where gene flow is low. We implemented these analyses to assess species boundaries in Southeast Asian toads, a group that is understudied and characterized by numerous unresolved species complexes.

RESULTS

Multilocus phylogenetic analyses showed that deep evolutionary relationships including the genera Sigalegalephrynus, Ghatophryne, Parapelophryne, Leptophryne, Pseudobufo, Rentapia, and Phrynoides remain unresolved. Comparison of genetic divergences revealed that intraspecific divergences among allopatric populations of Pelophyrne signata (Borneo vs. Peninsular Malaysia), Ingerophrynus parvus (Peninsular Malaysia vs. Myanmar), and Leptophryne borbonica (Peninsular Malaysia, Java, Borneo, and Sumatra) are consistent with interspecific divergences of other Southeast Asian bufonid taxa. Conversely, interspecific divergences between Pelophryne guentheri/P. api, Ansonia latiffi/A. leptopus, and I. gollum/I. divergens were low (< 3%) and consistent with intraspecific divergences of other closely related taxa. The BPP analysis produced variable results depending on prior settings and priors estimated from empirical data produced the best results that were also congruent with the gdi analysis.

CONCLUSIONS

This study showed that the evolutionary history of Southeast Asian toads is difficult to resolve and numerous relationships remain ambiguous. Although some results from the species delimitation analyses were inconclusive, they were nevertheless efficacious at identifying potential new species and taxonomic incompatibilities for future in-depth investigation. We also demonstrated the sensitivity of BPP to different priors and that careful selection priors based on empirical data can greatly improve the analysis. Finally, the gdi can be a robust tool to complement other species delimitation methods.