Newly described: Yangsan Clawed Salamander (Onychodactylus sillanus)

New publication through multiple collaborations including the description of Onychodactylus sillanus: Yangsan Clawed Salamander (양산꼬리치레도롱뇽)!

Onychodactylus sillanus in life. A: adult male from North Gyeongsang Province, Yangsan-si, Republic of Korea, in life; B: subadult paratype (CGRB 15907) from North Gyeongsang Province, Unmun Mountain,
Republic of Korea, in life.

For wildlife to be protected, it must first be known, as species that are not yet formally described are not the target of conservation attention, independently of threat levels. While habitat degradation has consistently increased across the last decades in the Republic of Korea, taxonomic and conservation efforts are lagging.

For instance, a clade of Onychodactylus clawed salamanders from the extreme southeast of the Korean Peninsula is known to have diverged circa 6.82 million years ago from its sister species O. koreanus, and despite the candidate species status of this lineage, its extremely restricted range is under intense anthropogenic pressure. Here, through the use of genetics, morphometrics and landscape modelling, we confirmed the species status of the southeast Korean Onychodactylus population and formally describe it as Onychodactylus sillanus (Yangsan Clawed Salamander; 양산꼬리치레도롱뇽).

Range, suitable habitat, and phylogenetic relationships of Onychodactylus sillanus.
A: Georeferenced occurrence points of Onychodactylus koreanus and Onychodactylus sillanus sp. nov. Collected occurrence points are based on our survey data as well as the Global Biodiversity Information Facility (GBIF), VertNet, EcoBank platform, and voucher specimens deposited in the Ewha Woman’s University Natural History Museum (EWNHM). Genetic samples and specimens originate from a selection of sites, and all datapoints were used to generate ecological niche models after spatial distance thinning. The same general data collection methodology and resulting occurrence dataset for O. koreanus are provided in Shin et al. (2021). B: Estimated area of Onychodactylus sillanus sp. nov. presence based on Minimum Convex Polygon (MCP) and binary presence area of Maxent output. Note: Maxent binary output (792.7 km2) estimated significantly broader area of presence than MCP (258.3 km2). Maxent output largely fell within higher elevation area of South Gyeongsang Province.
Map generated in QGIS v3.10. *: Maxent ranges are binary encoded for presence and absence based on the threshold determined in the Supplementary Materials. C: Maximum-likelihood consensus tree of the genus Onychodactylus derived from analysis of 1 153 bp cyt b, 654 bp COI, and 532 bp 16S rRNA gene fragments. Corresponding voucher specimen information, locality data, and GenBank accession numbers are given in Supplementary Table S3. Black circles indicate strongly supported nodes, empty circles indicate nodes with moderate support levels, no circles correspond to no node support. Numbers at tree nodes correspond to ML ultrafast-bootstrap (UFBS)/BI posterior probability (PP) support values. D, E: Onychodactylus sillanus sp. nov. in life: adult male from North Gyeongsang Province, Yangsan-si, Republic of Korea (D); larva from South Gyeongsang Province, Yangsan-si, Dong-myeon, Republic of Korea (E). F: Natural habitat of species in North Gyeongsang Province, Yangsan-si, Dong-myeon, Republic of Korea.

We then proceed to determine threats, habitat loss and risk of extinction based on climatic models under different Representative Concentration Pathways and following the IUCN Red List categories and criteria. We highlight a decrease in the extent of occurrence between 87.6% and 97.3 % within the next three generations based on several climate change scenarios, a decline high enough for the species to be listed as Critically Endangered based on the category A3 of the IUCN Red List of species. Our results will enable the development of protection programs and legitimise citizen activities protecting the population. A conservation action plan is a priority to coordinate the activities linked to the protection of the species.

Potential impacts of future climate change on the suitable habitat of Onychodactylus sillanus sp. nov. The ecological niche models projected on to four climate change scenarios under two timeframes all predicted significant and drastic contraction of suitable habitat area. Depending on the scenario and time frame, as much as 97% reduction of suitable habitat area was predicted. *The Maxent ranges is binary encoded for presence and absence based on the threshold determined in the text.

Borzée A., Shin Y., Poyarkov N. A., Jeon J. Y., Baek H. J., Lee C. H., An J., Hong Y. J., Min M-S. (2022).  Dwindling in the mountains: description of a critically endangered and microendemic Onychodactylus species (Amphibia, Hynobiidae) from the Korean Peninsula. Zoological Research. 43(5):750-755. DOI: 10.24272/j.issn.2095-8137.2022.048

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