A phylogeographic evaluation of the Amolops mantzorum species group: cryptic species and plateau uplift

A new species of Amolops (Amphibia, Anura, Ranidae) from Guizhou Province, China

The Torrent frogs of the genus Amolops are widely distributed in Nepal and northern India eastwards to southern China and southwards to Malaysia. The genus currently contains 84 species. Previous studies indicated underestimated species diversity in the genus. In the context, a new species occurring from the mountains in the northwestern Guizhou Province, China is found and described based on morphological comparisons and molecular phylogenetic analyses, Amolopsdafangensissp. nov. Phylogenetic analyses based on DNA sequences of the mitochondrial 16S rRNA and COI genes supported the new species as an independent lineage. The uncorrected genetic distances between the 16S rRNA and COI genes in the new species and its closest congener were 0.7% and 2.6%, respectively, which are higher than or at the same level as those among many pairs of congeners. Morphologically, the new species can be distinguished from its congeners by a combination of the following characters: body size moderate (SVL 43.2-46.8 mm in males); head length larger than head width slightly; tympanum distinct, oval; vocal sacs absent; vomerine teeth present; dorsolateral folds weak formed by series of glands; nuptial pads present on the base of finger I; heels overlapping when thighs are positioned at right angles to the body; tibiotarsal articulation reaching the level far beyond the tip of the snout when leg stretched forward.

Large X-effects are absent in torrent frogs with nascent sex chromosomes

Sex chromosomes are popularized as a special role in driving speciation. However, the empirical evidence from natural population processes has been limited to organisms with degenerated sex chromosomes, where hemizygosity is mainly considered to act as the driver of reproductive isolation. Here, we examined several hybrid zones of torrent frog Amolops mantzorum species complex, using an approach by mapping species-diagnostic loci onto the reference genome to compare sex-linked versus autosomal patterns of introgression. We find little support in sex-linked incompatibilities for large X-effects for these populations in hybrid zones with homomorphic sex chromosomes, due to the absence of the hemizygous effects. As expected, the large X-effects were not found in those with heteromorphic but newly evolved sex chromosomes, owing to the absence of strong genetic differences between X and Y chromosomes. The available data so far on amphibians suggest little role for sex-linked genes in speciation. The large X-effects in those with nascent sex chromosomes may not be as ubiquitous as presumed across the animal kingdom.

A new species of cascade frog (Anura: Ranidae: Amolops) from central Yunnan, China

A new species of the genus Amolops, Amolops ailao sp. nov., is described from central Yunnan, China. The new species belongs to the A. mantzorum species group. Phylogenetic analyses based on the combination of mitochondrial 16S rRNA, COI, and cytb genes revealed that the new species is the sister taxon to Amolops ottorum with strong support. Genetically, the new species differs from A. ottorum by 5.0% in cytb sequences. Morphologically, the new species can be distinguished from known congeners by the combination of the following characters: true dorsolateral folds absent, but dorsolateral folds formed by series of glands present; circummarginal groove on tip of first finger absent; body size small (males SVL 33.0-35.1 mm and female SVL 41.3 mm); HW/SVL 0.32‒0.35; UEW/SVL 0.08‒0.10; THL/SVL 0.52‒0.56; vomerine teeth absent; interorbital distance narrower than internarial distance; tympanum distinct, less than half eye diameter; supratympanic fold present, indistinct; a pair of large tubercles on sides of cloaca; tibiotarsal articulation reaching beyond anterior corner of eye; and vocal sac absent. The cladogenesis events within the A. mantzorum group rapidly occurred from Pliocene 4.23 Mya to Pleistocene 1.2 Mya, coinciding with the recent intensive uplift of the Qinghai-Tibetan Plateau since the Pliocene. Combining findings in this study with the most recent taxonomic progress, we consider that there are 20 known Amolops species in Yunnan, China, accounting for the highest proportion of amphibian diversity of Yunnan, and five of them belong to the A. mantzorum group. Among different subfauna and water systems in Yunnan, the species diversity of Amolops in northwestern Yunnan and Nu River Basin is highest.

Heterogeneous Evolution of Sex Chromosomes in the Torrent Frog Genus Amolops

In sharp contrast to birds and mammals, in numerous cold-blooded vertebrates, sex chromosomes have been described as homomorphic. This sex chromosome homomorphy has been suggested to result from the high turnovers often observed across deeply diverged clades. However, little is known about the tempo and mode of sex chromosome evolution among the most closely related species. Here, we examined the evolution of sex chromosome among nine species of the torrent frog genus Amolops. We analyzed male and female GBS and RAD-seq from 182 individuals and performed PCR verification for 176 individuals. We identified signatures of sex chromosomes involving two pairs of chromosomes. We found that sex-chromosome homomorphy results from both turnover and X–Y recombination in the Amolops species, which simultaneously exhibits heterogeneous evolution on homologous and non-homologous sex chromosomes. A low turnover rate of non-homologous sex chromosomes exists in these torrent frogs. The ongoing X–Y recombination in homologous sex chromosomes will act as an indispensable force in preventing sex chromosomes from differentiating.

A cryptic species of the Amolopsricketti species group (Anura, Ranidae) from China-Vietnam border regions

It was supposed that the current records of Amolopsricketti might be a species complex composed of multiple species. In this study, on the basis of wide sampling, we found that the records of A.ricketti from Yunnan, China, and northern Vietnam actually represent a cryptic species based on morphological and molecular evidence. Amolopsshihaitaoi sp. nov. can be distinguished from other members of the A.ricketti species group by its moderate body size (SVL 35.5‒37.3 mm in males and 39.2‒45.7 mm in females); white spines on the temporal region, loreal region, snout, and lips in breeding males but absent in females; overlapping heels; tibiotarsal articulation reaching tip of snout; indistinct longitudinal glandular folds on the skin of the shoulders; presence of supernumerary tubercles below the base of fingers II‒IV, distinct pineal body; presence of vomerine teeth; and absence of vocal sacs. Phylogenetic analysis supports that the new species is sister to Amolopsyatseni and the populations from Jingxi, Guangxi and Lào Cai, Vietnam previously reported as A.yatesni also belong to it. Additionally, our results indicate that more cryptic species may exist within the A.ricketti species group, implying that more studies are needed to achieve a complete understanding of the species diversity of this group.

The complete mitogenome of the Amolops jinjiangensis (Anura: Ranidae)

We describe the mitochondrial genome sequence of a torrent frog, Amolops jinjiangensis. The mitogenome was extracted and assembled for the first time by restriction site-associated DNA sequencing (RAD-seq). The total length is 17,780 bp, containing 13 protein-coding genes (PCGs), two ribosomal RNA genes, 22 transfer RNA genes, and one control region. The gene rearrangement was detected as the W-O_L-ANCY gene cluster which consisted with several published Amolops mitogenomes. The phylogenetic tree was constructed based on 13 protein-coding genes of A. jinjiangensis and 11 closely related species by Bayesian analyses.

A new species of Amolops (Anura: Ranidae) from northern Myanmar

A new species of the genus Amolops, Amolops putaoensis sp. nov., is described from northern Myanmar. The new species can be distinguished from its congeners by the following characters: (1) dorsolateral fold distinct; (2) upper-lip stripe white; (3) male body size 37.6-40.2 mm; (4) ground color of dorsal surface brown, flank green, small warts on dorsum; (5) two internal subgular vocal sacs present; (6) HL slightly shorter than HW; (7) two palmar tubercles present, supernumerary tubercles and outer metatarsal tubercle absent; (8) tympanum smaller than half of eye diameter; (9) vomerine teeth present; (10) tibiotarsal articulation reaching beyond snout tip; (11) supratympanic fold indistinct; (12) pineal body present; (13) finger webbing absent, presence of circummarginal groove on tip of first finger; (14) nuptial pads present. The population from Myanmar represented a distinct maternal lineage within the Amolops monticola group and was recovered as a sister taxon to Amolops aniqiaoensis with strong support (100) based on concatenated data. Average uncorrected pairwise distances ( P-distances) between the specimens from Myanmar and other species in the genus ranged from 2.69% (vs. A. aniqiaoensis) to 12.24% (vs. A. indoburmanensis) for 16S rRNA, 6.14% (vs. A. aniqiaoensis) to 15.79% (vs. A. panhai) for COI, and 9.66% (vs. A. aniqiaoensis) to 19.52% (vs. A. afghanus) for ND2.

Population demographic history and adaptability of the vulnerable Lolokou Sucker Frog

Amphibians are experiencing worldwide declines due to increasing anthropogenetic disturbances. However, the genetic variability and hence adaptability are still unknown for most frogs. We integrated the mitochondrial (ND2 gene), nuclear (TYR gene) and major histocompatibility complex (MHC) loci, to clarify the demographic patterns and immune-gene diversity of the Lolokou Sucker Frog (Amolops loloensis). Demographic analysis of the ND2 and TYR genes suggested that the Lolokou Sucker Frog experienced a population expansion within the last 10,000 years. High MHC diversity was detected, which has likely resulted from positive selection, indicating the current diversity bodes well for the species' adaptive potential to pathogenic challenges. These findings broaden our knowledge on the population history and evolution adaptation of the reclusive torrent frog, and conservation implications are provided.

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.

Development and characterization of twelve microsatellite loci for Amolops ricketti using next-generation sequencing

Amphibian populations have decreased dramatically because of human disturbance. To better conserve and manage native or wild populations of Amolops ricketti, 12 novel microsatellite loci were developed using high-throughput sequencing. The number of alleles ranged from 2 to 19, with an average of 7.67 alleles per locus. The observed and expected heterozygosity ranged from 0.42 to 1.00 (average 0.81) and from 0.51 to 0.95 (average 0.76), respectively. The polymorphism information content per locus ranged from 0.38 to 0.92 (average 0.69). These polymorphic microsatellite markers will contribute to the assessment of population structure, gene flow and genetic differentiation in A. ricketti.

A combined approach of mitochondrial DNA and anchored nuclear phylogenomics sheds light on unrecognized diversity, phylogeny, and historical biogeography of the torrent frogs, genus Amolops (Anura: Ranidae)

The genus Amolops ("torrent frogs") is one of the most species-rich genera in Ranidae, with 59 recognized species. This genus currently includes six species groups diagnosed mainly by morphology. Several recent molecular studies indicated that the classification of species groups within Amolops remains controversial, and key nodes in the phylogeny have been inadequately resolved. In addition, the diversity of Amolops remains poorly understood, especially for those from incompletely sampled regions. Herein, we investigate species-level diversity within the genus Amolops throughout southern China and Southeast Asia, and infer evolutionary relationships among the species using mtDNA data (16S, COI, and ND2). Molecular analyses indicate nine unnamed species, mostly distributed in the Himalayas. We then utilized anchored hybrid enrichment to generate a dataset representing the major mitochondrial lineages to resolve phylogenetic relationships, biogeography, and pattern of species diversification. Our resulting phylogeny strongly supports the monophyly of four previously identified species groups (the A. ricketti, A. daiyunensis, A. hainanensis, and A. monticola groups), but paraphyly for the A. mantzorum and A. marmoratus groups, as previously defined. We erect one new species group, the A. viridimaculatus group, and recognize Dubois' (1992) subgenus Amo as the A. larutensis species group. Biogeographic analysis suggests that Amolops originated on the Indo-Burma/Thai-Malay Peninsula at the Eocene/Oligocene boundary, and dispersed outward, exemplifying a common pattern observed for the origin of Asian biodiversity. The early divergence within Amolops coincides with the Himalayan uplift and the lateral extrusion of Indochina at the Oligocene/Miocene boundary. Our results show that paleoclimatic and geomorphological events have profoundly influenced the patterns of lineage diversification within Amolops.

Phylogenetic relationships of the Chinese torrent frogs (Ranidae: Amolops) revealed by phylogenomic analyses of AFLP-Capture data

The torrent frog genus Amolops contains nearly sixty species distributed in swift mountain streams throughout southeast Asia. The taxonomy of this genus has proven complicated due to unstable morphological diagnostic characters. The relationships of Amolops species and species groups were not readily resolved with a small number of molecular markers. Here, we applied the novel AFLP-Capture approach and acquired two large datasets (242 anonymous nuclear sequences and the mitochondrial genome) from 70 Chinese Amolops samples to study their relationships. The phylogenies inferred from the nuclear data and the mitochondrial data were both robust and revealed a primary phylogenetic split between eastern and western Chinese Amolops species. The relationships of the six species groups were clarified. While the three species groups in east China (the A. ricketti, A. daiyunensis and A. hainanensis groups) were monophyletic, the three species groups in the west (the A. mantzorum, A. monticola and A. marmoratus groups) were not monophyletic, suggesting a need for further investigation and revision. The robust phylogenies also provided new insights into species relationships, especially for the A. mantzorum group, which has been difficult to resolve due to multiple speciation events occurring approximately 7-8 million years ago. The divergence times estimated with the nuclear data indicated that the ancestor of the Chinese Amolops appeared in the late Eocene or early Oligocene, and that speciation events in the Chinese Amolops were often related to geological events (e.g. the uprising of mountains and the formation of islands). By including the mitochondrial sequences from GenBank, a more comprehensive Amolops phylogeny was constructed that reflected the origin of the Chinese Amolops. Based on all these results, a dispersal scenario of the torrent frogs was hypothesized. Our research serves as the first example of using AFLP-Capture to obtain a large amount of data for shallow-scale phylogenetic and taxonomic studies, which should be useful for other nonmodel organism groups.

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.

Chromosomal Evolution in the Amolops mantzorum Species Group (Ranidae; Anura) Narrated by Repetitive DNAs

In an attempt to analyze the organization of repetitive DNAs in the amphibian genome, 7 microsatellite motifs and a 5S rDNA sequence were synthesized and mapped in the karyotypes of 5 Amolops species. The results revealed nonrandom distribution of the microsatellite repeats, usually in the heterochromatic regions, as found in other organisms. These microsatellite repeats showed rapid changes among Amolops species, documenting the recent evolutionary history within this lineage. In contrast, 5S rDNA was localized in chromosomes 5 of all species, suggesting that these chromosomes are homologous within the monophyletic clade. Furthermore, the heteromorphic X and Y sex chromosomes (chromosomes 5) of A.mantzorum, had identical patterns of 5S rDNA, indicating that the subtelocentric Y resulted from a pericentric inversion. Several microsatellite repeats were found in the heteromorphic sex chromosomes, verifying the association of repetitive DNAs with sex chromosome differentiation in A. mantzorum.

Description of two cryptic species of the Amolopsricketti group (Anura, Ranidae) from southeastern China

Two cryptic species, which were previously reported as Amolopsricketti, are revealed on the basis of significant morphological and genetic divergences. Amolopssinensissp. n. from central Guangdong, northeastern Guangxi and southwestern Hunan can be distinguished by the longitudinal glandular folds on the skin of the shoulders and other character combinations. Amolopsyatsenisp. n. from the coastal hills of west Guangdong can be distinguished by the dense tiny round translucent, or white, spines on the dorsal skin of the body, dorsal and dorsolateral skin of the limbs, and other character combinations. The phylogenetic interrelationships of the A.ricketti group have been inferred as (A.wuyiensis + A.ricketti) + (A.yunkaiensis + (A.albispinus + (A.sinensissp. n. + A.yatsenisp. n.))). This work indicates that the current records of A.ricketti might be a species complex composed of multiple species, and further work is needed to figure out this puzzle.

The first complete mitochondrial genome sequence of Nanorana parkeri and Nanorana ventripunctata (Amphibia: Anura: Dicroglossidae), with related phylogenetic analyses

Members of the Nanorana genus (family Dicroglossidae) are often referred to as excellent model species with which to study amphibian adaptations to extreme environments and also as excellent keystone taxa for providing insights into the evolution of the Dicroglossidae. However, a complete mitochondrial genome is currently only available for Nanorana pleskei. Thus, we analyzed the complete mitochondrial genomes of Nanorana parkeri and Nanorana ventripunctata to investigate their evolutionary relationships within Nanorana and their phylogenetic position in the family Dicroglossidae. Our results showed that the genomes of N. parkeri (17,837 bp) and N. ventripunctata (18,373 bp) encode 13 protein‐coding genes (PCGs), two ribosomal RNA genes, 23 transfer RNA (tRNA) genes, and a noncoding control region. Overall sequences and genome structure of the two species showed high degree of similarity with N. pleskei, although the motif structures and repeat sequences of the putative control region showed clear differences among these three Nanorana species. In addition, a tandem repeat of the tRNA‐Met gene was found located between the tRNA‐Gln and ND2 genes. On both the 5′ and 3′‐sides, the control region possessed distinct repeat regions; however, the CSB‐2 motif was not found in N. pleskei. Based on the nucleotide sequences of 13 PCGs, our phylogenetic analyses, using Bayesian inference and maximum‐likelihood methods, illustrate the taxonomic status of Nanorana with robust support showing that N. ventripunctata and N. pleskei are more closely related than they are to N. parkeri. In conclusion, our analyses provide a more robust and reliable perspective on the evolutionary history of Dicroglossidae than earlier analyses, which used only a single species (N. pleskei).

The potential colonization histories of Opsariichthys bidens (Cyprinidae) in China using Bayesian binary MCMC analysis

Vicariance and/or long-distance dispersal shape the distribution patterns of many extant taxa, and orogenesis and/or climate fluctuations are key factors that drive the events of vicariance and/or dispersal. In this study, we yielded biogeographical inferences from Bayesian binary MCMC (BBM) analysis to explore the potential colonization histories of Opsariichthys bidens in China and to identify potential factors responsible for the colonization histories. Many vicariance and dispersal events were identified. The results suggested that O. bidens seemed to have originated from the Yangtze River and/or the Pearl River and experienced a Yangtze River-Pearl River split at 7.04 million years ago (Ma). BBM analysis revealed that the Pearl River populations had undergone expansions to the Hainan drainages, the Lancangjiang River (upper Mekong) and the Nanpanjiang River (upper branch of the Pearl River) at 0.74 Ma. Meanwhile, the Yangtze River populations expanded to the northeastern drainages during the Early Pleistocene. Subsequently, the northeastern drainages dispersed to the Yellow River during the Middle Pleistocene. More recently, the northeastern drainage populations also dispersed to the Huaihe River and back to the Yangtze River. A portion of the Pearl River populations originated from the Yangtze River dispersed to the Jiulongjiang River during the Middle Pleistocene. These time scales fit well with the uplift of the Qinghai-Tibet Plateau and Pleistocene glacial cycles, indicating the two factors played vital roles in shaping the colonization histories of O. bidens.

CLADES: A classification-based machine learning method for species delimitation from population genetic data

Species are considered to be the basic unit of ecological and evolutionary studies. As multilocus genomic data are increasingly available, there have been considerable interests in the use of DNA sequence data to delimit species. In this study, we show that machine learning can be used for species delimitation. Our method treats the species delimitation problem as a classification problem for identifying the category of a new observation on the basis of training data. Extensive simulation is first conducted over a broad range of evolutionary parameters for training purposes. Each pair of known populations is combined to form training samples with a label of "same species" or "different species". We use support vector machine (SVM) to train a classifier using a set of summary statistics computed from training samples as features. The trained classifier can classify a test sample to two outcomes: "same species" or "different species". Given multilocus genomic data of multiple related organisms or populations, our method (called CLADES) performs species delimitation by first classifying pairs of populations. CLADES then delimits species by maximizing the likelihood of species assignment for multiple populations. CLADES is evaluated through extensive simulation and also tested on real genetic data. We show that CLADES is both accurate and efficient for species delimitation when compared with existing methods. CLADES can be useful especially when existing methods have difficulty in delimitation, for example with short species divergence time and gene flow.

A new species of the genus Amolops (Anura: Ranidae) from high-altitude Sichuan, southwestern China, with a discussion on the taxonomic status of Amolops kangtingensis

A new species of the genus Amolops Cope, 1865 is described from Xinduqiao, Kangding, Sichuan. It was previously identified as Amolops kangtingensis, which is synonymized to Amolops mantzorum in this study. The new species, Amolops xinduqiao sp. nov., is distinguished from all other congeners by the following combination of characters: (1) medium body size, adult males SVL 41.2–47.5 mm (n=15, average 43.9 mm), adult females SVL 48.5–56.6 mm (n=15, average 52.5 mm); (2) head length equal to width or slightly wider than long; (3) tympanum small, but distinct; (4) vomerine teeth in two tiny rows, separated by a space about one vomerine teeth row; (5) bony projections on lower jaw absent; (6) dorsolateral folds usually absent; (7) tarsal folds or glands on tarsus absent; (8) circummarginal groove on disc of finger Ⅰ absent; (9) tibiotarsal articulation reaching nostril or beyond; (10) webs of toe IV reaching to distal articulation, other toes fully webbed to disc; and (11) vocal sac absent in males.

Next-generation sequencing of mixed genomic DNA allows efficient assembly of rearranged mitochondrial genomes in Amolops chunganensis and Quasipaa boulengeri

Recent improvements in next-generation sequencing (NGS) technologies can facilitate the obtainment of mitochondrial genomes. However, it is not clear whether NGS could be effectively used to reconstruct the mitogenome with high gene rearrangement. These high rearrangements would cause amplification failure, and/or assembly and alignment errors. Here, we choose two frogs with rearranged gene order, Amolops chunganensis and Quasipaa boulengeri, to test whether gene rearrangements affect the mitogenome assembly and alignment by using NGS. The mitogenomes with gene rearrangements are sequenced through Illumina MiSeq genomic sequencing and assembled effectively by Trinity v2.1.0 and SOAPdenovo2. Gene order and contents in the mitogenome of A. chunganensis and Q. boulengeri are typical neobatrachian pattern except for rearrangements at the position of "WANCY" tRNA genes cluster. Further, the mitogenome of Q. boulengeri is characterized with a tandem duplication of trnM. Moreover, we utilize 13 protein-coding genes of A. chunganensis, Q. boulengeri and other neobatrachians to reconstruct the phylogenetic tree for evaluating mitochondrial sequence authenticity of A. chunganensis and Q. boulengeri. In this work, we provide nearly complete mitochondrial genomes of A. chunganensis and Q. boulengeri.

Species Delimitation in the Genus Moschus (Ruminantia: Moschidae) and Its High-Plateau Origin

The authenticity of controversial species is a significant challenge for systematic biologists. Moschidae is a small family of musk deer in the Artiodactyla, composing only one genus, Moschus. Historically, the number of species in the Moschidae family has been debated. Presently, most musk deer species were restricted in the Tibetan Plateau and surrounding/adjacent areas, which implied that the evolution of Moschus might have been punctuated by the uplift of the Tibetan Plateau. In this study, we aimed to determine the evolutionary history and delimit the species in Moschus by exploring the complete mitochondrial genome (mtDNA) and other mitochondrial gene. Our study demonstrated that six species, M. leucogaster, M. fuscus, M. moschiferus, M. berezovskii, M. chrysogaster and M. anhuiensis, were authentic species in the genus Moschus. Phylogenetic analysis and molecular dating showed that the ancestor of the present Moschidae originates from Tibetan Plateau which suggested that the evolution of Moschus was prompted by the most intense orogenic movement of the Tibetan Plateau during the Pliocene age, and alternating glacial-interglacial geological eras.

Characterization of the mitochondrial genome of Amolops tuberodepressus (Anura: Ranidae)

Amolops tuberodepressus is a vulnerable torrent frog, and only know distributed in the Wuliang Mountain in southwestern China. In the present study, the mitochondrial DNA (mtDNA) sequence of A. tuberodepressus was determined. The genome was 18 348 bp in length, and it contained 37 genes (13 protein-coding genes, two ribosomal RNAs, and 22 transfer RNAs), one partial control region and one light strand replication origin. The gene rearrangement was observed within the WANCY tRNA gene cluster region, which similar to other Amolops species. In this paper, we utilized 13 protein-coding genes of A. tuberodepressus and other 10 closely ranid species to construct the species phylogenetic tree to verify the A. tuberodepressus was accuracy.