 |
| Cyrtodactylus laevis Ma, Wang & Jiang, in Ma, Shi, Qian, Sui, Wang et Jiang, 2024. Smooth Bent-Toed Geckos | 光滑裸趾虎 || www.mdpi.com/2076-2615/14/16/2384 |
Abstract
A new Cyrtodactylus species, C. laevis sp. nov., from the dry-hot valleys near the Yarlung Zangbo River in Re Village, Jindong Countryside, Lang County, Linzhi City, Xizang Autonomous Region, China, is described herein based upon the integrative taxonomic results combining molecular phylogenetic systematics and morphological characteristic comparisons. Our molecular phylogeny was inferred by combining three mitochondrial gene fragments (16S/CO1/ND2), and it indicated a distinct differentiation between the new species and C. tibetanus species complex, with obvious genetic distances (16S 9.9–11.8%/CO1 16.5–18.2%/ND2 16.6–18.5%) detected, supporting its validity. Morphologically, the new species can be easily distinguished from its congers by the following characters: (1) medium size (SVL 48.58–50.92 mm), (2) tubercles on dorsum sparse, (3) tail segments absent and tubercles on tails absent, (4) supralabials 10–12 and infralabials 8–10, (5) interorbital scales between anterior corners of the eyes 28–32, (6) scale rows at midbody 96–98, (7) ventral scales between mental and cloacal slit 145–153, (8) ventral scale rows 41–45, and (9) 4 to 5 white–yellow transverse bands with brown dots and black merges between the nape and sacrum. The description of C. laevis sp. nov. increased the total species number of C. tibetanus group to three, and the total Cyrtodactylus species number in Xizang to six and in China to eleven. The new species is currently only known from the type locality with its extremely small populations and needs future surveys to reveal its distribution range, population status, natural history, and mechanisms so that the new species can coexist with Altiphylax medogense.
Keywords: Cyrtodactylus laevis sp. nov.; taxonomy; molecular phylogeny; morphological characters; Yarlung Zangbo River
 |
| General view of the Cyrtodactylus laevis sp. nov. (CIB 121655) paratype in life: (A) total dorsal view of body, (B) total ventral view of body, (C) dorsal view of medium dorsum, (D) dorsal view of head, (E) right-side view of head, (F) left-side view of head, and (G) ventral-side view of head. Photos by Sheng-Chao Shi. |
Cyrtodactylus laevis sp. nov. Ma, Wang and Jiang, 2024
Diagnosis. (1) Medium size (SVL 48.58–50.92 mm); (2) tubercles on dorsum are sparse; (3) tail segments are absent and tubercles on tails are absent; (4) supralabials 10–12 and infralabials 8–10; (5) interorbital scales between anterior corners of the eyes 28–32; (6) scale rows at midbody 96–98; (7) ventral scales between mental and cloacal slit 145–153; (8) ventral scale rows 41–45; (9) four to five white–yellow transverse bands with brown dots and black merges between the nape and sacrum.
 |
| Morphological comparisons of species in the Cyrtodactylus tibetanus group: (A) Cyrtodactylus laevis sp. nov. (CIB 121655), (B) C. tibetanus (CIB QZ2021214), (C) C. tibetanus (CIB QZ2021219), and (D) C. zhaoermii (CIB XZ2024101). Red arrows indicate the tubercles on dorsum and blue arrows indicate the tail segments and the tubercles on tails. (A–C) Photos by Sheng-Chao Shi, and (D) photo by Shun Ma. |
Etymology. This specific epithet refers to its tubercles-sparse skin surface. We suggest “Smooth Bent-Toed Geckos” as its English common name and “光滑裸趾虎” (Guāng Huá Luŏ Zhĭ Hŭ) as its Chinese common name.
Distribution and habitats. This new species is only known to be distributed in Re Village, Jindong Countryside, Lang County, Linzhi City, Xizang Autonomous Region, China. The elevation is 3065 m a.s.l. We found the specimens under a rock in the dry-hot valleys near the Yarlung Zangbo River on a sunny afternoon (AT 26 °C, RH 42%; Figure 6), so we consider that it is a nocturnal species. Moreover, Altiphylax medogense (Zhao and Li, 1987) and Laudakia sacra (Smith, 1935) were also found inhabiting the same area.
 |
| Habitats of Cyrtodactylus laevis sp. nov. Photos by Shun Ma. |
Simple Summary: More than 350 species (32 species groups) of Cyrtodactylus Gray, 1827, are reported currently, with a wide distribution from Himalaya, South Asia, Southeast Asia, to Melanesia. Cyrtodactylus tibetanus group, as the earliest Cyrtodactylus diverging clade, are endemic to the Yarlung–Tsangpo River Basin of Tibetan Plateau, only containing two species: C. tibetanus and C. zhaoermii. However, two newly collected Cyrtodactylus specimens from the eastern region of Lang County, Linzhi City, Xizang Autonomous Region, China, were found to be an unnamed taxon of this group based upon the molecular phylogeny, which was conducted using a concatenation data matrix (the partial 16S ribosomal RNA gene (16S), the partial cytochrome c oxidase subunit 1 gene (CO1), and the partial NADH dehydrogenase subunit 2 gene (ND2)) and morphological comparisons, as the new species could be easily identified from other C. tibetanus group species through the absence of the tubercles on dorsum, tail segments, and the tubercles on tails. The new species is currently only known from the type locality with its extremely small populations, with great demand for future investigations to figure out its distribution range, population status, natural history, and mechanisms so that this new species can coexist with Altiphylax medogense.
Shun Ma, Sheng-Chao Shi,Tian-Yu Qian, Lu-Lu Sui, Bin Wang and Jian-Ping Jiang. 2024. A New Species of Cyrtodactylus tibetanus Group (Reptilia: Squamata: Gekkonidae) from Xizang Autonomous Region, China. Animals. 14(16), 2384. DOI: 10.3390/ani14162384
