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| Tylototriton koliaensis Poyarkov, Nguyen, S.X. Le, D.X. Le, Arkhipov, Gorin, Hernandez & Dufresnes, 2024 Cao Bang Crocodile Newt || Researchgate.net/publication/385746634 |
Using molecular (mitochondrial DNA, multilocus genomic loci) and phenotypic (morphology, coloration, osteology) analyses, we reveal a new cryptic species of crocodile newt of the Tylototriton asperrimus species group from Viet Bac Mountain Range, northern Vietnam. The new species was previously confounded with T. asperrimus, T. vietnamensis and more recently T. ziegleri, its closest relative, from which it can be distinguished by a combination of diagnostic characters at phenotypic traits including rib nodules, cranial bony ridges, skin granulation, orange spotting patterns, vomerine teeth shape and relative limb size. General differences in body shape between the new species and T. ziegleri s. str. are further corroborated by multivariate morphological analyses. Phylogenetic analysis of the ND2 and 16S rRNA mtDNA gene fragments (1665 bp) confirm the placement of the new species in the subgenus Yaotriton as the sister species of T. ziegleri s. str. (p-distance 2.7 % in the ND2 gene). Furthermore, the differentiation of the two species is fully supported by the analysis of 3901 genomic loci (556,209 bp) obtained by double digest RAD-sequencing. The new species is presently isolated in the northeastern parts of the Viet Bac Massif (Ngan Son Mountain Range) while T. ziegleri s. str. is restricted to its western part (Song Gam Mountain Range); their respective ranges are presumably separated by the Gam River Valley. The new species is probably threatened by extinction on the short term, being currently known only from montane evergreen broadleaf forests (~1000–1400 m of elevation) in the Nguyen Binh and Bao Lac districts of Cao Bang Province of Vietnam, but potentially extending to Jingxi County in the adjacent Guangxi Province of China. Our study emphasizes the benefits of relatively new technologies such as high-throughput sequencing and X-ray microtomography for the integrative taxonomy of cryptic, closely related amphibian species, and brings research on the iconic genus Tylototriton into the genomic era.
Keywords: 16S rRNA, Cao Bang Province, ddRAD-seq, endemism, Gam River, micro-CT scanning, mtDNA genealogy, ND2, taxonomy, Tylototriton ziegleri
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| Distribution of Tylototriton koliaensis sp. nov. (red), T. ziegleri s. str. (blue) and T. thaiorum (green) in northern Indochina. A, map of Indochina, the inset shows the area of the studied species. B, localities of the studied species; see Table 1 for locality details. Dots show type localities. Locality 4 was not confirmed with molecular data and should be regarded as Tylototriton cf. koliaensis sp. nov. |
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| Specimens of Tylototriton koliaensis sp. nov. in life from Kolia Mountain Pass, Phia Oac-Phia Den National Park, Nguyen Binh, Cao Bang Province, Vietnam. A, holotype ZMMU A-8157, female, in situ; B, paratype ZMMU A-8158, male, in situ. Photographs by Nikolay A. Poyarkov. |
Tylototriton koliaensis Poyarkov, Nguyen, Le, Le, Arkhipov, Gorin, Hernandez & Dufresnes, sp. nov.
Cao Bang Crocodile Newt
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| Holotype of Tylototriton koliaensis sp. nov. (ZMMU A-8157, female) in preservative. A, dorsal view; B, ventral view; C, head, dorsal view; D, head, ventral view; E, head, lateral view; F, palmar view of right hand; G, plantar view of left foot; H, ventral view of cloacal area. Photographs by Nikolay A. Poyarkov. |
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| Specimens of Tylototriton ziegleri s. str. in life. A, male ZMMU A-8167 from Thanh Van Village, Quang Ba, Bat Dai Son Nature Reserve, Ha Giang Province, Vietnam, in situ; B, male from Chieu Lau Thi Mt., Ha Giang Province, Vietnam, in situ (not collected); C, male from Wenshan, Yunnan Province, China, in situ (not collected). Photographs by Nikolay A. Poyarkov (A), Loi Phuoc Tran (B), and Yinpeng Zhang (C). |
Nikolay A. POYARKOV, Tan Van NGUYEN, Son Xuan LE, Dac Xuan LE, Dmitriy V. ARKHIPOV, Vladislav A. GORIN, Axel HERNANDEZ and Christophe DUFRESNES. 2024. Multiple Lines of Evidence for A New Cryptic Species of Tylototriton (Amphibia, Salamandridae) from northern Vietnam. Alytes. 41(1-4); 56-98.
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