Sexual Dimorphism in the Chinese Endemic Species Hynobius maoershanensis (Urodela: Hynobiidae).

Sexual dimorphism is common in most vertebrate species and has diverse manifestations. The study of sexual dimorphism has critical significance for evolutionary biological and ecological adaptation. In this study, we analysed the morphometric data of Hynobius maoershanensis, a rare and endangered species, to examine sexual dimorphism in size and shape. A total of 61 H. maoershanensis individuals (9 adult females and 52 adult males) were used in this study. We measured 14 morphological variables and weight of each individual. Analysis of covariance using snout-vent length (SVL) as the covariate showed significant differences in head width (HW), tail length (TL), tail height (TH), forelimb length (FLL), hindlimb length (HLL) and space between axilla and groin (AGS) between the male and female. The female AGS was greater than that of the male, whereas males had greater HW, TL, TH, FLL and HLL than females. The findings show that sexual dimorphism is present in terms of shape but not in terms of size. The wider head of the male could improve mating success, and its thicker limbs and longer tail might facilitate courtship. The females' wider AGS may increase reproductive output. Our results support sexual dimorphism in H. maoershanensis, which could be explained by the sexual selection and fecundity theory hypothesis.

Variation in the intestinal microbiota at different developmental stages of Hynobius maoershanensis.

Intestinal microbiota play an important role in the life of amphibians and its composition may vary by developmental stage. In this study, 16S rRNA high-throughput sequencing was used to profile the intestinal microbiota of Hynobius maoershanensis, which exclusively inhabit the Maoer Mountain swamp at an altitude of approximately 2,000 m. We characterized the bacterial composition, structure, and function of the microbiota of H. maoershanensis at different developmental stages. The alpha diversity was not markedly different for the Simpson, Shannon, Ace, and Sobs indices of microbes. The beta diversity revealed that there were age-related differences in the structure of the intestinal microbes of H. maoershanensis, specifically, at the phylum level. Bacteroidetes and Proteobacteria were the dominant bacteria present in the adult stage, and the relative abundance of Bacteroidetes was significantly higher compared with that of tadpoles. Firmicutes and Proteobacteria were the dominant phylum during the tadpole stage and their relative abundance was significantly higher compared with the adult period. Functional analysis revealed that the pathways associated with organismal systems and metabolism were significantly enriched in the adults, whereas human diseases, genetic information processing, and cellular processes were more enriched in the hindlimb bud stage. Human diseases and environmental information processing were more enriched in the forelimb bud stage at KEGG pathway level 1. Possibilities for the observed discrepancies include the adaptation to eating habits and the remodeling of the intestines during development. We speculated that H. maoershanensis adults may be more suitable to a high-fiber diet, whereas the tadpoles are associated with a carnivorous diet. Our study provides evidence of variations in the intestinal microbiota during development in amphibians, highlighting the influence of historical developments on the intestinal microbiota and an increased understanding of the importance of physiological characteristics in shaping the intestinal microbiota of amphibians. These data will help us formulate more effective protection measures for H. maoershanensis.

DNA barcoding revises a misidentification on mossy frog: new record and distribution extension of Theloderma corticale Boulenger, 1903 (Amphibia: Anura: Rhacophoridae).

As an endangered animal group, mossy frog (genus Theloderma) has attracted the attention of biologists and wildlife conservationists. Clarifying the taxonomic status and distribution of each species in Theloderma is important to determine the conservation status for each species, establish appropriate conservation strategies and probe the speciation process. Recently, we discovered a medium-sized species of mossy frog of the genus Theloderma in April 2015 during municipal surveys of amphibians in Dayao Mountain of Jinxiu. It was collected from the water-filled tree cavities. However, there remains some uncertainty about the species determination of the mossy frog in the Yinshan station of Dayao Mountain in Guangxi Province, China. Previously, the mossy frog in Guangxi Province was recognized as Th. kwangsiense. In order to clarify the species status of the mossy frog obtained from Guangxi, we sequenced 2414 bp of the 12S and 16S genes in the sample collected from the Dayao Mountain. Combining all the sequence in NCBI, genetic analyses from the data suggest that the sample from the Dayao Mountain is Th. corticale rather than Th. kwangsiense. It is most likely that the most previous studies had wrong species identification. And, it is the first time we use DNA barcoding to prove that the species obtained from Guangxi is a new distribution of Th. corticale.

The complete mitochondrial genome of the Hynobius maoershanensis (Caudata: hynobiidae).

The Hynobius maoershanensis is a member of hynobiidae, endemic to Mountain Maoer in Guangxi province, China. It was first found and reported in 2006 and so far there is a little molecular research about it. The complete mitochondrial genome of H. maoershanensis has been obtained for the first time in this study. The circular genome (16,412 bp in length) consisted of 37 typical animal mitochondrial genes (13 protein-coding genes, 22 transfer RNA genes, 2 ribosomal RNA genes) and 1 control region. Overall base composition of the complete mitochondrial DNA was 33% A, 32% T, 21% C, and 14% G with AT (65%).

Genetic diversity and population demography of the Chinese crocodile lizard (Shinisaurus crocodilurus) in China.

The Chinese crocodile lizard Shinisaurus crocodilurus is a critically endangered species, listed in Appendix II of CITES. Its populations and habitat in China have undergone significant changes in recent years. Understanding the genetic variability and phylogeography of this species is very important for successful conservation. In this study, samples were taken from 11 wild ponds and two captive populations in China. We sequenced mitochondrial CYTB, partial ND6, and partial tRNA-Glu and genotyped 10 microsatellite loci. Our analyses of these data showed low genetic variability, no strong isolation caused by distance, and a lack of a phylogeographic structure in this species. Based on our results, the basal divergence between two clades of S. crocodilurus in China may have been caused by the formation of the Pearl River system. We found a population expansion in one of these clades. Microsatellite analysis indicated the presence of three clusters, separated by significant genetic differences. We found that most individuals in the two captive populations were from the Luokeng (Guangdong) and Guangxi wild source populations, respectively.