Being the largest extant amphibian in the world, the IUCN Critically Endangered Chinese giant salamander Andrias davidianus is a charismatic species with great international public interest. While threats such as commercial overexploitation and habitat degradation have been extensively documented to affect natural populations of A. davidianus, still no information is available about the species sensitivity to climate change. Here, we develop an ensemble of species distribution models (SDMs) for A. davidianus and projected its habitat suitability under present‐day and future climate change scenarios. We based our SDMs on bioclimatic and topographic predictors, and recent (2012–2018) field‐collected occurrence data across the whole distribution range of the species. The ensemble SDMs exhibited good predictive capacity and suggested that slope, maximum temperature of warmest month, precipitation of driest month, and isothermality are the most influential predictors in determining distribution patterns in this species. The projections of our models point to a pronounced impact of climate changes over A. davidianus, with more than two‐thirds of its suitable range expected to be lost in all scenarios of future climates tested. In concert with the numerous other threats that are affecting this species, climate change poses a serious hindrance to the long‐term survival of A. davidianus. We emphasise the urgent need of undertaking strict measures to manage this species and safeguard the few remaining available suitable habitats. We suggest that adaptive management strategies including designation of new reserves should be considered to mitigate the impacts of climate change on A. davidianus.

Understanding genetic diversity patterns of endangered species is an important premise for biodiversity conservation. The critically endangered salamander Andrias davidianus , endemic to central and southern mainland in China, has suffered from sharp range and population size declines over the past three decades. However, the levels and patterns of genetic diversity of A. davidianus populations in wild remain poorly understood. Herein, we explore the levels and phylogeographic patterns of genetic diversity of wild‐caught A. davidianus using larvae and adult collection with the aid of sequence variation in (a) the mitochondrial DNA (mtDNA) fragments ( n = 320 individuals; 33 localities), (b) 19 whole mtDNA genomes, and (c) nuclear recombinase activating gene 2 ( RAG2 ; n = 88 individuals; 19 localities). Phylogenetic analyses based on mtDNA datasets uncovered seven divergent mitochondrial clades (A–G), which likely originated in association with the uplifting of mountains during the Late Miocene, specific habitat requirements, barriers including mountains and drainages and lower dispersal ability. The distributions of clades were geographic partitioned and confined in neighboring regions. Furthermore, we discovered some mountains, rivers, and provinces harbored more than one clades. RAG2 analyses revealed no obvious geographic patterns among the five alleles detected. Our study depicts a relatively intact distribution map of A. davidianus clades in natural species range and provides important knowledge that can be used to improve monitoring programs and develop a conservation strategy for this critically endangered organism.

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The complete mitochondrial genome of Vanmanenia pingchowensis was determined in this study. The gene composition, arrangement and transcriptional orientation in V. pingchowensis mitogenome were identical to most vertebrates. The complete mitogenome of V. pingchowensis was 15,560 bp in size with 13 protein coding genes, 22 tRNA genes, and a control region. Two start codon patterns and three stop codon patterns were found in protein-coding genes. Only the tRNA-Ser2 could not fold into a typical clover-leaf secondary structure for lacking the dihydrouridine arm. Sequences alignment results suggest that the complete mitogenome of V. pingchowensis is an efficient tool to study molecular phylogenetics, biogeography and adaptive evolution of this lineage.

The complete mitochondrial genome of Elopichthys bambusa was determined in this study. The gene composition, arrangement and transcriptional orientation in E. bambusa mitogenome were identical to most vertebrates. Two start codon patterns (ATG and GTG) and three stop codon patterns (TAG, TAA and T) were found in protein-coding genes. Only the tRNA-Ser2 could not fold into a typical clover-leaf secondary structure for lacking the dihydrouridine arm. Sequences alignment results suggest that the complete mitogenome of E. bambusa is an efficient tool to check species identification by comparing different gene sequences.

Featured Application: Authors are encouraged to provide a concise description of the specific application or a potential application of the work. This section is not mandatory. Abstract:The Chinese sturgeon, Acipenser sinensis, is a large anadromous and highly endangered protected species. The assessment of its breeding population in the Yangtze River is critically important for effective management and population preservation. Currently, hydroacoustic methods have been widely used to study the adult sturgeons in the river, whereas the acoustic target strength (TS) characteristics of the species have not been studied. In this study, the TS of Chinese sturgeon was carefully evaluated both by ex situ measurements and theoretical calculations. Six Chinese sturgeons (Body Length (BL): 74.0−92.6 cm) were measured by a 199 kHz split echosounder in a 10-m deep net cage. The computed tomography of a Chinese sturgeon (BL: 110.0 cm) was conducted and the Kirchhoff ray mode (KRM) method was used to estimate the theoretical TS. As a result, the mean ex situ TS range of the six specimens was from −26.9 to −31.4 dB, which was very close to the KRM estimation (~1 dB difference). Then, the KRM method was used to predict the TS of Chinese sturgeon as a function of BL in six frequencies commonly used in freshwater environments and to estimate the TS of a representative adult Chinese sturgeon (250 cm) as a function of frequency and tilt angle. This study can provide a good basis for future hydroacoustic studies on the critically endangered Chinese sturgeon.

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