How little is known about "the little brown frogs": description of three new species of the genus Leptobrachella (Anura: Megophryidae) from Yunnan Province, China

Description of a new Asian Leaf Litter Toad of the genus Leptobrachella Smith, 1925 (Anura, Megophryidae) from southern Guizhou Province, China

Background

The Asian leaf litter toads of the genus Leptobrachella Smith, 1925 (Anura, Megophryidae) inhabit the forest floor and rocky streams in hilly evergreen forests and are widely distributed from southern China, west to north-eastern India and Myanmar, through mainland Indochina to Peninsular Malaysia and the Island of Borneo.

New information

A new species of the Asian leaf litter toad genus Leptobrachella from Guizhou Province, China is described. Molecular phylogenetic analyses, based on mitochondrial 16S rRNA and COI genes and nuclear RAG1 gene sequences indicated that the new species is genetically divergent from its congeners. The new species could be distinguished from its congeners by a combination of the following characters: (1) body of medium size in males (SVL 31.9 - 32.9 mm); (2) distinct black spots present on flanks; (3) toes rudimentarily webbed, with wide lateral fringes; (4) skin on dorsum shagreened with fine tiny granules and short ridges; (5) heels overlapped when thighs are positioned at right angles to the body; (6) tibia-tarsal articulation reaching interior corner of the eye.A new species of the Asian leaf litter toad genus Leptobrachella from Guizhou Province, China is described. Molecular phylogenetic analyses, based on mitochondrial 16S rRNA and COI genes and nuclear RAG1 gene sequences indicated that the new species is genetically divergent from its congeners. The new species could be distinguished from its congeners by a combination of the following characters: (1) body of medium size in males (SVL 31.9 - 32.9 mm); (2) distinct black spots present on flanks; (3) toes rudimentarily webbed, with wide lateral fringes; (4) skin on dorsum shagreened with fine tiny granules and short ridges; (5) heels overlapped when thighs are positioned at right angles to the body; (6) tibia-tarsal articulation reaching interior corner of the eye.

Two new species of Leptobrachella Smith 1925 (Amphibia: Megophryidae) from Cao Bang Province, Vietnam

Two new species, Leptobrachella phiaoacensis sp. nov. and Leptobrachella phiadenensis sp. nov., are described from Phia Oac-Phia Den National Park, Cao Bang Province, Vietnam based on genetic divergence and morphological differences. Leptobrachella phiaoacensis sp. nov. is characterized by a combination of the following characters: size medium (27.833.3 mm in five adult males and 31.541.8 mm in five adult females); head longer than wide; tympanum distinct; dorsal skin shagreened with fine tubercles; toes webbing rudimentary, with narrow lateral fringes; supratympanic fold edged by a distinct black line; the presence of a dark brown triangle in interorbital region and a W-shaped marking in scapular region; belly from pinkish white to white with dark brown specking on belly periphery; iris bicolored copper in upper part, fading to silvery grey in lower part. Leptobrachella phiadenensis sp. nov. is distinguished from its congeners by a combination of the following morphological characters: size medium (27.628.6 mm in two adult females); head wider than long; tympanum distinct; skin on dorsal head and body rough with warts, tubercles and dermal ridges; toes webbing rudimentary, with narrow dermal fringes; supratympanic fold orange; dorsal surface of head and body with some large dark brown markings, a dark brown triangle in interorbital region, edged in white; flank light brown with some dark flecks; belly white with dark specking on outer margins; iris bicolored, copper in upper part, fading to silvery grey in lower part. In terms of genetic distance, the two new species differ from each other and other congeners for which comparable sequences are available by at least 3.7% (16S rRNA gene). Recognition of these new species brings the total number of known species in the genus Leptobrachella from Vietnam to 34.

First national record of Microhylahmongorum Hoang, Nguyen, Phan, Pham, Ninh, Wang, Jiang, Ziegler and Nguyen, 2022 (Anura, Microhylidae, Microhyla) in China

Background

To date, 10 species of the genus Microhyla have been recorded in China, of which six were distributed in Yunnan Province. Microhylahmongorum Hoang, Nguyen, Phan, Pham, Ninh, Wang, Jiang, Ziegler, and Nguyen, 2022 was also speculated to be distributed in Xishuangbana, Yunnan Province, China. However, there is no evidence of documentation of M.hmongorum.

New information

We report the first country record of Microhylahmongorum, based on specimens collected from Yunnan border region. Morphologically, the specimen was consistent with the original descriptions of M.hmongorum. Phylogenetically, the sequences of the specimens from China clustered with the sequence of type specimens of M.hmongorum from Vietnam, with uncorrected pairwise distances of 0.9% at the 16S gene fragment analysed. Therefore, we report M.hmongorum as a new record species in China.

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 Asian leaf litter toad of the genus Leptobrachella (Amphibia, Anura, Megophryidae) from central south China

A new species of the Asian leaf litter toad genus Leptobrachella from central south China is described. Molecular phylogenetic analyses, based on mitochondrial 16S rRNA and nuclear RAG1 gene sequences indicated the new species as an independent clade in the genus. The new species could be distinguished from its congeners by a combination of the following characters: body of medium size (SVL 29.2–34.2 mm in 15 adult males and 34.4–43.1 mm in seven adult females); distinct black spots present on flanks; toes rudimentary webbed, with wide lateral fringes; ventral belly white with distinct nebulous brown speckling on ventrolateral flanks; skin on dorsum shagreened with fine tiny granules or short ridges; iris copper above, silver below; heels overlapped when thighs are positioned at right angles to the body; tibia-tarsal articulation reaches the middle eye; dorsal surface of tadpole semi-transparent light brown, spots on tail absent, keratodont row formula I: 3+3/2+2: I; call series basically consist of repeated long calls, at dominant frequency (5093 ± 412 Hz).

A new species of the genus Leptobrachella (Anura, Megophryidae) from northwestern Guangdong Province, China

The genus Leptobrachella is a species-rich genus of megophrid frog. Rapid discovery of many new species within this genus emphasizes the importance of regional research. In this study, we describe a new species of Leptobrachella, Leptobrachella verrucosasp. nov., from northwestern Guangdong Province, China, based on a combination of molecular and morphological data. A key including congeners from the same province, namely L. laui, L. liui, L. mangshanensis, L. shimentaina, and L. yunkaiensis, is provided.

A new Leptobrachella species (Anura, Megophryidae) from South China, with comments on the taxonomic status of L. chishuiensis and L. purpurus

A new species of Leaf Litter Toad, Leptobrachella shimentainasp. nov., is described from the Shimentai and Luokeng nature reserves of northern Guangdong Province, southern China. The new taxon can be distinguished from all recognized congeners by a combination of discrete morphological character state differences relating to its small body size (SVL 26.4–28.9 mm in six adult males, 30.1 and 30.7 mm in two adult females); a number of apparently fixed color pattern character differences (including eye coloration and color pattern features from dorsal, ventral, and dorsolateral surfaces of its head, body, limbs, and ventrum); the morphological and discrete characteristics of the external phenotype (the skin texture of dorsum and ventrum, the presence of supra-axillary and ventrolateral glands, the wide dermal fringes and rudimentary webbing on toes, and the uninterrupted longitudinal ridges under toes). Two samples of this new species previously were proposed as representing a new, unnamed species. We now substantiate this claim by providing diagnostic comparisons of discrete character differences. In addition, we also discuss taxonomic uncertainty surrounding the identity of two congeners, L. chishuiensis and L. purpurus, which we interpret as indicative of taxonomic inflation in the species-rich subfamily Megophryidae.

Historical mitochondrial genome introgression confounds species delimitation: Evidence from phylogenetic inference in the odorrana grahami species complex

Species delimitation is essential to informing conservation policy and understanding ecological and evolutionary processes. Most of our recent gains in knowledge on animal diversity rely on morphological characteristics and mitochondrial (mt) DNA variation. Concordant results based on both have led to an unprecedented acceleration in the identification of new species and enriched the field of taxonomy. However, discordances are also found commonly between morphological and mtDNA evidence. This confounds species delimitation, especially when gene flow or mitochondrial genome introgression has occurred. Here we illustrate how mitochondrial genome introgression among species of the Odorrana grahami complex confounds species delimitation using the combined evidence of morphological characters, mitochondrial variation, and thousands of nuclear single nucleotide polymorphisms (SNPs) from genotyping-by-sequencing (GBS). Fifty-eight samples across the distribution of the O. grahami complex were included. The mtDNA matrilineal genealogy indicated two clades, with O. grahami and O. junlianensis clustered together. In contrast, all nuclear evidence including gene trees, species trees, and genetic structure analyses based on GBS data support three species with distinct genetic clusters. These three distinct genetic clusters also correspond to distinct morphological characters. They affirm the distinct taxonomic entities of both O. grahami and O. junlianensis, as well as a third clade distinct from either. Which species the third clade belongs to remains unclear and will require further testing. The nuclear genomic loci contradict the COI evidence, with indications of rampant historical mitochondrial genome introgression among the species of the O. grahami complex. These discordant signals previously confused species delimitation efforts in this group. Based on these findings, we recommend the integration of independent data, especially nuclear genomic evidence, in species delimitation so as to be robust against the pitfalls of mitochondrial introgression.

Distribution extension of Leptobrachella eos (Ohler, Wollenberg, Grosjean, Hendrix, Vences, Ziegler & Dubois, 2011): first record from Thailand

We report the first country record of Leptobrachella eos (Ohler, Wollenberg, Grosjean, Hendrix, Vences, Ziegler & Dubois, 2011) from Thailand, based on one specimen collected from Chom poo Phuka nature trail, Bo Kluea District. Morphologically, the specimen displayed good agreement with the original descriptions provided for L. eos. Phylogenetically, the specimens clustered according to the sequences of type locality of L. eos. Notably, our discovery increases the number of Leptobrachella species known to occur in Thailand to nine.

Confirmation of Leptobrachellaventripunctata (Fei, Ye, and Li, 1990), based on molecular and morphological evidence in Thailand

Background

Thailand is considered a global biodiversity hotspot that is known to harbour a striking diversity of endemic species. However, several research studies have determined that the level of amphibian diversity in the country has been significantly underestimated. The megophryid genus Leptobrachella Smith, 1925 is currently known to include 89 species that are primarily distributed throughout southern China and Southeast Asia; however, only seven species have been found in Thailand.

New information

Based on an integrative approach encompassing genetic and morphological analyses, we have concluded that the population identified from Chiang Rai Province of Thailand is conspecific with Leptobrachellaventripunctata (Fei, Ye, and Li, 1990). Importantly, this is the first confirmation record of this species, based on molecular and morphological evidence in Thailand. The discovery of this species reaffirms that the diversity within the genus has been underestimated with many species yet to be discovered. In addition, the findings of our study further highlight the lack of existing knowledge on amphibian taxonomy and an underestimation of the biodiversity that exists along these national border areas.

A new species of Leptobrachella (Anura, Megophryidae) from Mount Pu Ta Leng, northwest Vietnam

The Hoang Lien Range in northwest Vietnam is known to harbour five species of Leptobrachella, a specious genus of terrestrial frogs. We collected specimens of Leptobrachella from Mount Pu Ta Leng on the second highest peak in the Hoang Lien Range and use morphological and molecular data to show that this population represents a previously undescribed species which we name Leptobrachella graminicola sp. nov. after the abundance of calling males on sedge-like plants. This new species is closely related to L. bourreti but the new species is distinguished from L. bourreti and other congeneric species by a combination of the following characters: (1) a body size range of 23.124.6 mm in six adult males and 28.632.9 mm in five adult females; (2) skin on dorsum smooth, with many tubercles and lacking dermal ridges; (3) toes with rudimentary webbing and broad lateral fringes; (4) belly white with brown spots; (5) throat dark brown with light grey-brown flecks and spots; (6) a row of large white spots on the outer edge of the tarsus extending from the heel to the inner metatarsal tubercle, sometimes forming a long white stripe; and (7) a bicoloured iris. The new, high-elevation species is likely to be range-restricted and threatened by habitat loss and the activities of tourists.

A new species of the Asian leaf litter toad genus Leptobrachella Smith, 1925 (Anura, Megophryidae) from northwest Guizhou Province, China

A new species of the Asian leaf litter toad genus Leptobrachella is described from Guizhou Province, China. Molecular phylogenetic analyses support the new species as an independent lineage deeply nested in the Leptobrachella clade. The new species is distinguished from its congeners by a combination of the following morphological characters: body size medium (SVL 29.7–31.2 mm in five adult males); dorsal skin shagreened, some of the granules forming longitudinal short skin ridges; tympanum distinctly discernible, slightly concave; supra-axillary, femoral, pectoral and ventrolateral glands distinctly visible; absence of webbing and lateral fringes on fingers; toes with narrow lateral fringes but without webbing; heels overlapping when thighs are positioned at right angles to the body; tibia-tarsal articulation reaching the middle of eye when leg stretched forward. The discovery highlighted the underestimated species diversity in the Leptobrachella toads in southwestern China.

A new species of the genus Leptobrachella Smith, 1925 (Anura, Megophryidae) from Guizhou, China

Asian leaf-litter toads of the genus Leptobrachella represent charismatic anuran diversification with 80 species, of which 25 are from China. Recent new discoveries suggest that the diversity of this genus is underestimated. Here, we describe a new species of Leptobrachella, Leptobrachella bashaensis sp. nov. from the Basha Nature Reserve, Congjiang County, Guizhou Province, China. The new species is distinguished from its congeners by the following suite of morphological traits: small body size (SVL 22.9-25.6 mm in six adult males and 27.1 mm in one adult female); head longer than wide; dorsal skin slightly shagreened with small tubercles; creamy-white chest and belly with irregular black spots; distinct ventrolateral glands forming a white line; finger webbing and fringes absent; toe webbing rudimentary and lateral fringes narrow; iris bicolored with bright orange in upper half and silver in lower half; dorsal surface of tadpole head dark brown with small, brown, irregular spot, air sac-shaped bulges on both sides of body. The new species differs from all known congeners by an uncorrected p-distance of >5.3% of the 16S rRNA gene fragment examined, and the phylogenetic analysis clusters the new species with L. maoershanensis and L. laui. At present, the new species is only known from a small range of montane evergreen secondary forests in Basha Nature Reserve approximately 900 m elevation. Its natural history and conservation status are discussed.

Two new Leptobrachella species (Anura, Megophryidae) from the Yunnan-Guizhou Plateau, southwestern China

Two new toad species of the genus Leptobrachella are described from the Yunnan-Guizhou Plateau of China, based on the combination of molecular and morphological data. The description of Leptobrachellaaspera Wang, Lyu, Qi & Wang, sp. nov. from Huanglianshan Nature Reserve represents the thirteenth Leptobrachella species known from Yunnan Province, and the description of Leptobrachelladorsospina Wang, Lyu, Qi & Wang, sp. nov. from Yushe Forest Park represents the sixth Leptobrachella species known from Guizhou Province. These new discoveries further emphasize the extremely high diversity of the Leptobrachella toads in these regions.