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| Gekko tesselatus Xu, Ma, Cai, Qi, Matsukoji, Poyarkov, Sun, Jiang & Peng, in Xu, Ma, Cai, Qi, Matsukoji, Poyarkov, Sun, Weng, Gu, Tian, Zhang, Jiang et Peng, 2025. Checkered Gecko | 斑纹壁虎 || DOI: doi.org/10.3897/zse.101.175246 |
Abstract
We describe a new rock-dwelling species of the genus Gekko (subgenus Japonigekko) from Heishui County, Aba Tibetan and Qiang Autonomous Prefecture, Sichuan Province, China, based on both morphological and molecular (1,574 bp from the mitochondrial 16S rRNA and ND2 genes) evidence. Morphologically, Gekko tesselatus sp. nov. is characterized by its moderate body size; two (rarely one) enlarged postmentals; flattened dorsal tubercles extending from the posterior head through the neck to the anterior portion of the tail, arranged in 12–15 rows at midbody; 130–157 ventral scales between the mental and the cloacal slit; 98–106 midbody scale rows; 31–39 ventral scale rows; subdigital lamellae numbering 7–10 on finger I, 9–12 on finger IV, 7–9 on toe I, and 9–12 on toe IV; absence of webbing; 6–8 precloacal pores in males and absence in females; one (rarely two) postcloacal tubercle on each side; and a distinctive dorsal coloration. Phylogenetically, the new species forms a distinct clade within the subgenus Japonigekko, showing uncorrected 16S sequence divergences of at least 8.2% from its closest relative, G. liboensis, and at least 8.9% from all other congeners, as well as ND2 divergences of at least 14.3% from G. fengshanensis and at least 14.9% from other species in the subgenus. The discovery of this new species raises the number of Japonigekko species recorded in China to 26 and in Sichuan Province to seven.
Key Words: Gekko tesselatus sp. nov., molecular phylogeny, morphological characters, taxonomy
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| Holotype of Gekko tesselatus sp. nov. in life. A. Dorsal view; B. Ventral view; C. Dorsal view of head; D. Lateral view of head; E. Ventral view of head. Photographs by Yuhao Xu. |
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| Coloration of Gekko tesselatus sp. nov. in life. A. Specimen QHU R2025022, adult female; B. Specimen QHU R2025023, adult male; C. Specimen QHU R2025024, adult female; D. Specimen QHU R2025025, adult male; E. Specimen QHU R2025026, subadult male; F. Specimen SYS r003029, adult male. Photographs by Yuhao Xu. |
Gekko tesselatus Xu, Ma, Cai, Qi, Matsukoji, Poyarkov, Sun, Jiang & Peng, sp. nov.
Diagnosis. Gekko tesselatus sp. nov. can be diagnosed from other Japonigekko species by the following unique combination of characters: (1) a moderate body size (SVL reaches up to 64.9 mm in males and 72.9 mm in females); (2) nares in contact with the rostral, internasal 0 or 1; (3) two enlarged postmentals, rarely one; (4) flattened dorsal tubercles present from the posterior head through the neck to the anterior portion of the tail, arranged in 12–15 rows at midbody; (5) 130–157 ventral scales between the mental and the cloacal slit; (6) 98–106 midbody scale rows; (7) 31–39 ventral scale rows; (8) subdigital lamellae 7–10 on finger I, 9–12 on finger IV, 7–9 on toe I, and 9–12 on toe IV; (9) webbing absent; (10) 6–8 precloacal pores in males, absent in females; (11) one postcloacal tubercle on each side, rarely two; (12) in life, the dorsum is predominantly greyish brown, with a series of irregular dark transverse bands that are faintly interrupted medially by a narrow vertebral stripe and laterally fragmented and interconnected, forming an irregular, checkerboard-like reticulated pattern.
Etymology. The specific name “tesselatus” is a Latinized adjective in the nominative singular (masculine gender), derived from “tessella” (a small square tile), and means “reticulated” or “checkerboard-like.” It refers to the characteristic dorsal pattern of the new species, which consists of a series of irregular dark transverse bands that are faintly interrupted medially by a narrow vertebral line and, laterally, are partly fragmented and partly interconnected, forming an irregular, checkerboard-like reticulated pattern across the dorsum. For the common names, we suggest “Checkered Gecko” in English and “Bān Wén Bì Hǔ” (斑纹壁虎) in Chinese.
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| Habitat and field observations of Gekko tesselatus sp. nov. A. Macrohabitat of the new species in Se’ergu Town, Heishui County, Sichuan, China; B. Microhabitat of the new species; C. Gekko tesselatus sp. nov. in life, in situ; D. The sympatric Lycodon multizonatus. Photographs by Yuhao Xu (A–C) and Tianxuan Gu (D). |
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| Comparison of Gekko tesselatus sp. nov. and four closely related species in life, in situ. A. Gekko tesselatus sp. nov., unvouchered adult male individual from Se’ergu, Heishui, Sichuan, China; B. Gekko tesselatus sp. nov., unvouchered juvenile individual from Se’ergu, Heishui, Sichuan, China; C. G. liboensis, unvouchered individual from Libo, Guizhou, China; D. G. fengshanensis, NHMG 202408007, adult male from Fengshan, Guangxi, China; E. G. kwangsiensis, unvouchered adult female individual from Nanning, Guangxi, China; F. G. paucituberculatus, unvouchered individual from Baise, Guangxi, China. Photographs by YHX (A, B), Dan-Yang Zhou (C, F), reproduced from Huang et al. (2025) (D), and Yang (2015) (E). |
Yuhao Xu, Shun Ma, Bo Cai, Shuo Qi, Tomoya Matsukoji, Nikolay A. Poyarkov, Fanyue Sun, Shiyang Weng, Tianxuan Gu, Kaidi Tian, Di Zhang, Jianping Jiang and Lifang Peng. 2025. A New Rock-dwelling Gecko of the Subgenus Japonigekko (Squamata, Gekkonidae, Gekko) from northwestern Sichuan Province, China. Zoosystematics and Evolution. 101(4): 2221-2242. DOI: doi.org/10.3897/zse.101.175246