Chinese Salamander Research Articles

Sexual dimorphism in the Chinese endemic species Pachyhynobius shangchengensis Fei, Qu and Wu, 1983 (Urodela: Hynobiidae).

Sexual dimorphism (SD) is a widespread phenomenon in most vertebrate species and is exhibited in a myriad of ways. In amphibians, sexual size dimorphism, in which females are larger than males, is the most common type, and sexual shape dimorphism varies among species. Different selection forces (sexual selection, fecundity selection, and ecological selection) that act differently upon the sexes form the consequence of SD. Thus, studies of SD provide information about the general intersexual divergence of the same species and allow insights into the impact of selective forces on the sexes. In this study, we analyzed morphometric data of the Shangcheng stout salamander, Pachyhynobius shangchengensis, an endemic and poorly known Chinese salamander, to examine sexual dimorphism in size and shape. The morphometric data included 15 characteristics of 68 females and 55 males which were analyzed using univariate and multivariate methods. A significant difference was found between the sexes in terms of both body size (snout-vent length) and some body shapes (e.g., head length and width, tail length and width, distance between limbs, and limb length and width) in this salamander. The longer snout-vent length in males may be attributed to sexual selection, longer and wider head in males may contribute to male-male competition, longer and wider tail in males may be attributed to energy storage and reproductive success, the larger distance between limbs in females is likely due to a fecundity advantage, and longer and more robust limbs in males may be related to reproductive or competitive behaviors. These results demonstrated that sexual dimorphism of different morphological traits is the consequence of different selection forces that act differently upon the sexes.

Widespread occurrence of an emerging fungal pathogen in heavily traded Chinese urodelan species

AbstractUnderstanding introduction routes for wildlife pathogens is vital for the development of threat abatement plans. The chytrid fungus Batrachochytrium salamandrivorans (Bsal) has recently emerged in Europe, where it is considered to be a serious threat for urodelan conservation. If the highly diverse Chinese urodelans were to constitute a Bsal reservoir, then the significant international trade in these species may vector Bsal into naïve urodelan communities. Here, we analyzed a total of 1,143 samples, representing 36 Chinese salamander species from 51 localities across southern China for the presence of Bsal. We found Bsal was present across a wide taxonomic, geographical, and environmental range. In particular, Bsal DNA was detected in 33 samples from the genera Cynops, Pachytriton, Paramesotriton, Tylototriton, and Andrias, including the heavily traded species Paramesotriton hongkongensis and Cynops orientalis. The true Bsal prevalence across our data set was estimated between 2% and 4%, with a maximum of 50% in a population of P. hongkongensis. Even at this overall relatively low Bsal prevalence, the exportation of millions of animals renders Bsal introduction in naïve, importing countries a near certainty, which calls for the urgent implementation of proper biosecurity in the international wildlife trade.

Sexual size and shape dimorphism in the Wushan salamander, Liua shihi (Liu, 1950) (Urodela: Hynobiidae)

Sexual dimorphism in size or shape is widespread in the animal world. Many studies have explored this topic, but few have focused on Asian salamanders. In this study, we analyzed morphometric data of the Wushan salamander Liua shihi, an endemic Chinese salamander, to examine sexual dimorphism in size and shape. We evaluated data sets that included 17 morphometric characteristics of 61 females and 55 males using univariate and multivariate methods. Results show that sexual dimorphism in this species includes not only body size (males have a longer snout-vent length than females), but also shape (females have a longer space between axilla and groin and head size than males, while males have greater limb size). This article discusses the evolution of intersexual dimorphism according to models of ecology, fecundity and sexual selection. We propose that sexual dimorphism of body size can be attributed to sexual selection and local climates, that AGS may contribute to fecundity selection, that head size may be attributed to reproductive roles and ecology, and that limb size may be beneficial for reproductive success. However, most aspects of the reproductive biology, ecology and life history of this species remain unknown. This article fills a gap in the literature on this species and builds a foundation for future research. Research on such species is increasingly important as many species of salamander are becoming threatened or endangered throughout the world.

Transcriptomic analysis of endangered Chinese salamander: identification of immune, sex and reproduction-related genes and genetic markers.

BackgroundThe Chinese salamander (Hynobius chinensis), an endangered amphibian species of salamander endemic to China, has attracted much attention because of its value of studying paleontology evolutionary history and decreasing population size. Despite increasing interest in the Hynobius chinensis genome, genomic resources for the species are still very limited. A comprehensive transcriptome of Hynobius chinensis, which will provide a resource for genome annotation, candidate genes identification and molecular marker development should be generated to supplement it.Principal FindingsWe performed a de novo assembly of Hynobius chinensis transcriptome by Illumina sequencing. A total of 148,510 nonredundant unigenes with an average length of approximately 580 bp were obtained. In all, 60,388 (40.66%) unigenes showed homologous matches in at least one database and 33,537 (22.58%) unigenes were annotated by all four databases. In total, 41,553 unigenes were categorized into 62 sub-categories by BLAST2GO search, and 19,468 transcripts were assigned to 140 KEGG pathways. A large number of unigenes involved in immune system, local adaptation, reproduction and sex determination were identified, as well as 31,982 simple sequence repeats (SSRs) and 460,923 putative single nucleotide polymorphisms (SNPs).ConclusionThis dataset represents the first transcriptome analysis of the Chinese salamander (Hynobius chinensis), an endangered species, to be also the first time of hynobiidae. The transcriptome will provide valuable resource for further research in discovery of new genes, protection of population, adaptive evolution and survey of various pathways, as well as development of molecule markers in Chinese salamander; and reference information for closely related species.

Cytogenic studies of Hynobiidae (Urodela). XIV. Analysis of the chromosome of a Chinese salamander, Batrachuperus pinchonii (David).

The chromosome number of a Chinese salamander, Batrachuperus pinchonii, was re-examined Adults and embryonic specimens had a diploid number of 66, with 33 bivalents during meiosis, in contrast to previous reported results. Furthermore, when C-banding analysis was performed with embryos, chromosomes with banding patterns homoeologous to those of Salamandrella keyserlingii and Hynobius species were found. It appears, therefore, that Batrachuperus, Salamandrella and Hynobius might be derived from a common ancestral species in eastern Asia.

Thresholds and escalation of antipredator responses in the Chinese salamander Cynops cyanurus: inter- and intra-individual variation

Aspects of the control of antipredator behavior, including short- and long-term response modifications, were examined for the Chinese salamander Cynops cyanurus. Salamanders were tested for their antipredator behavior following repeated contact with the flicking tongue of a predatory snake. In a given trial, a salamander was contacted ten times by the snake and within-trial escalation or reduction in response was monitored. For each salamander, trials were repeated 6 times at 21-day intervals to test for long-term changes in response threshold and extent of escalation, and to identify consistent differences in behavior among individuals. The salamanders were found to escalate their antipredator responses over the ten stimuli within trials. They were significantly more responsive to tongue contacts late in a given trial than to the initial stimuli. They also showed long-term, among-trial decreases in the threshold to initial response and increases in the mean responses to the first tongue contacts. However, there was no significant long-term change in maximum response threshold or in the mean responses to the final tongue contacts. Variation among individuals in thresholds and responses was considerable and was consistent over trials.