Gekko tesselatus Xu, Ma, Cai, Qi, Matsukoji, Poyarkov, Sun, Jiang & Peng, 2025

Xu, Yuhao, Ma, Shun, Cai, Bo, Qi, Shuo, Matsukoji, Tomoya, Poyarkov, Nikolay A., Sun, Fanyue, Weng, Shiyang, Gu, Tianxuan, Tian, Kaidi, Zhang, Di, Jiang, Jianping & Peng, Lifang, 2025, A new rock-dwelling gecko of the subgenus Japonigekko (Squamata, Gekkonidae, Gekko) from northwestern Sichuan Province, China, Zoosystematics and Evolution 101 (4), pp. 2221-2242 : 2221-2242

Gekko tesselatus Xu, Ma, Cai, Qi, Matsukoji, Poyarkov, Sun, Jiang & Peng sp. nov.

Figs 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , Tables 4 , 5 , 6

Type material.

Holotype • CIB 119371 (Field no. LFR 2025142), adult male, from Se’ergu Town , Heishui County, Aba Tibetan and Qiang Autonomous Prefecture, Sichuan Province, China ( 31.9531°N, 103.3971°E; 1,847 m asl.), collected by Yuhao Xu, Fanyue Sun, and Jiaxiang Wu on 3 August 2025 .

Paratypes (N = 13, all from Sichuan Province, China) • QHU R 2025022 (Field no. LFR 2025143, adult female) • QHU R 2025023 (Field no. LFR 2025144, adult male) • QHU R 2025024 (Field no. LFR 2025145, adult female), with the same collecting information as the holotype • QHU R 2025025 (Field no. LFR 2025146, adult male), from Longba Town , Heishui County ( 31.9855°N, 103.3503°E; 2,047 m asl.), collected by Yuhao Xu, Fanyue Sun and Jiaxiang Wu on August 04, 2025 • QHU R 2025026 (Field no. LFR 2025147, subadult male), from Se’ergu Town , Heishui County ( 31.9290°N, 103.4211°E; 1,827 m asl.), collected by Yuhao Xu, Fanyue Sun and Jiaxiang Wu on August 4, 2025 • SYS r 003029 (Field no. LFR 2025148, adult male) • SYS r 003030 (Field no. LFR 2025149, adult female), from Se’ergu Town , Heishui County ( 31.9260°N, 103.44324°E; 1,886 m asl.), collected by Yuhao Xu, Fanyue Sun and Jiaxiang Wu on August 4, 2025 • SYS r 003031 (Field no. LFR 2025150, adult female) • SYS r 003032 (Field no. LFR 2025151, subadult female), from the same locality as the holotype, collected by Yuhao Xu, Fanyue Sun and Jiaxiang Wu on August 4, 2025 • CIB 119372 ( adult female) • CIB 119373 ( adult female) • CIB 119374 ( adult female) • CIB 119375 ( subadult female), from Se’ergu Town , Heishui County ( 31.9650°N, 103.3966°E; 1,938 m asl.), collected by Bo Cai in July, 2025 .

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.

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.

Description of the holotype.

(Fig. 3 ). An adult male specimen with original tail. Size medium, SVL 61.4 mm; body slender and trunk relatively elongate, AGD 29.0 mm, AGD / SVL ratio 0.47; tail slightly longer than body, distinctly swollen at base, oval in section, TAL 72.3 mm, TAL / SVL ratio 1.19.

Head depressed, noticeably longer than wide, and clearly separated from the neck, HL 17.09 mm, HW 12.31 mm, HH 5.00 mm, HH / HL ratio 0.29, HL / HW ratio 1.39. Snout obtuse, round anteriorly, ESD 7.14 mm, ESD / HL ratio 0.42. Eye large, ED 3.89 mm, ED / HL ratio 0.23; pupil vertical, featuring crenulated edges. Ear opening small, approximately elliptical, obliquely oriented, EL 1.12 mm, EL / ED ratio 0.29.

Rostral approximately rectangular in shape, wider than the high, RW 2.31 mm, RH 1.46 mm, RW / RH ratio 1.58. Nares oval, rounded by the rostral, 1 st supralabial, one distinctly enlarged supranasal, and three slightly enlarged nasals posteriorly; internasals absent. Preorbitals 18 / 17, preorbital region deeply concave; interorbital scales between the anterior corners of eyes 24; supralabials 10 / 10; infralabials 9 / 9. Mental pentagonal, wider than long, MW 1.80, ML 1.42, MW / ML ratio 1.27; mental narrower than the rostral, RW / MW ratio 1.28; postmentals two, enlarged, twice as long as wide, touching the mental and the first infralabial on both sides and three gular scales posteriorly. Tubercles present on the dorsal surface of the head behind the eyes; granular scales on the anterodorsal region of the head are larger than those on the posterior region.

Dorsal scales smooth, round to oval, granular, and juxtaposed; tubercles flattened, irregularly arranged, extending from the posterior part of the head to the anterior one-third of the tail, forming approximately 14 rows at midbody, surrounded by 8–9 dorsal scales. Ventrolateral fold present, without tubercles; ventrals slightly larger than dorsals, smooth, imbricate, and largest in middle of belly; ventral scale rows at midbody 36; scale rows around midbody 106; ventral scales in a row between mental and cloacal slit 138; precloacal scales enlarged, but no enlarged scales on thighs; precloacal pores 6 (Fig. 4 A ), situated at the distal of each scale, the tips of the two central scales are slightly inclined laterally, separating the precloacal pores at the midline into two groups (3 / 3); postcloacal tubercle 1 / 1 (Fig. 5 A ), large, surrounded by several smaller tubercles delineated by shallow grooves. Dorsal scales of tail flat and smooth, irregular in size, with a few tubercles present on the anterior one-third of the tail; subcaudals small at the base, distinctly enlarged beyond the swollen portion, and arranged in a longitudinal row.

Forelimbs and hindlimbs well developed; dorsal surface of forelimbs without tubercles, but dorsal surface of hindlimbs bearing tubercles; no webbing between the fingers and toes; digits moderately dilated; fingers and toes II – IV clawed; claws laterally compressed, extending beyond the terminal lamellae; no webbing between fingers and toes; subdigital lamellae undivided, under manus 7-9 - 10 - 11 - 9 (left) / 7-8 - 9 - 11 - 9 (right), and under pes 8-8 - 10 - 11 - 8 (left) / 8-8 - 11 - 11 - 10 (right); relative length of fingers and toes I <II <V <III <IV.

Coloration of the holotype in life.

(Fig. 6 ). In life, the dorsal ground color of the head and body is light greyish-brown, scattered with small dark brown to yellowish-brown spots. A faint W-shaped dark marking extending anteriorly from the occipital region to the posterior corners of the eyes. On the lateral sides of the head, a dark longitudinal stripe running from the posteroventral corner of the eye to the ear opening. Eight irregular dark transverse bands between the nape and the sacrum. The dark bands faintly divided along the midline by a narrow, light-colored vertebral line running intermittently from the nape to the tail tip. Laterally, the bands partly fragmented and interconnected, forming an irregular reticulated pattern reminiscent of a checkerboard. All dark markings and bands consist of a mixture of yellowish-brown and dark brown spots. The dorsal surfaces of the limbs bearing irregular dark transverse or reticulated markings. The tail light greyish-brown at the base, gradually becoming paler posteriorly, and bearing 12 dark transverse bands; the tail tip dark brown. The head and ventral surfaces of the body uniformly creamy white, while the ventral surface of the tail pale yellowish-white.

After capture, the overall body color becomes paler, turning yellowish-brown, and the dark markings on the dorsum become blurred. However, after being kept in captivity for several days, the color pattern gradually returns to its original state, even when housed in a white container.

Coloration of the holotype in preservation.

(Fig. 3 ). In preservative, the dorsal ground color of the head, body, and limbs turns grey, with the yellowish-brown spots on the dorsum disappearing, while the dark brown markings remained distinct; the ventral surface faded to greyish-white.

Variation.

The main morphological characters of Gekko tesselatus sp. nov. are summarized in Table 4 . The species exhibits no evident sexual dimorphism in morphometric ratios, scale counts, or coloration. The longest known male measures SVL 64.9 mm, with TAL 72.9 mm ( QHU R 2025025 ); and the female measures SVL 65.3 mm, with TAL 65.1 + mm ( QHU R 2025022 ); TAL / SVL ratio 1.07–1.23. Head depressed, noticeably longer than wide, and clearly separated from the neck, HL / HW ratio 1.16–1.47. Snout obtuse, round anteriorly, ESD / HL ratio 0.38–0.43. Eye large; pupil vertical, featuring crenulated edges. Ear opening small, approximately elliptical, obliquely oriented, EL / ED ratio 0.19–0.40, and EL / HL ratio 0.04–0.08.

Rostral rectangular in shape, wider than high; NS 3 or 4; INS 0 or 1; PO 12–15, preorbital region deeply concave; IOS 24; SL 10 or 11; IL 9–12. Mental pentagonal, narrower than the rostral; PM 2 ( 1 in specimen SYS r 003031 ); GP 3–6. Dorsal scales smooth, round to oval, granular, and juxtaposed, MBSR 98–106; tubercles flattened, irregularly arranged, extending from the posterior part of the head to the anterior part of the tail, DTR 12–15, GSDT 7–9; ventrals slightly larger than dorsals, smooth, imbricate, and largest in middle of belly, VS 31–39, SMC 130–157; precloacal scales enlarged, but no enlarged scales on thighs. PP 6–8 in males, situated at the distal of each scale; in CIB 119371 , QHU R 2025026 , and SYS r 003029 , the tips of the two central scales are laterally inclined, separating the precloacal pores into two groups (3 / 3); QHU R 2025023 also has 6 PP (3 / 3), but the central are separated by two intervening scales; in QHU R 2025025 , all 8 PP are arranged continuously (Fig. 4 ); PP absent in females. PAT 1 on each side (2 on the left side only in specimen SYS r 003029 ), large in males and surrounded by several smaller tubercles delineated by shallow grooves (Fig. 5 ); in females, the postcloacal tubercles are smaller and less distinct. Dorsal scales of tail flat and smooth, irregular in size, with a few tubercles present on the anterior part of the tail; subcaudals small at the base, distinctly enlarged beyond the swollen portion, and arranged in a longitudinal row.

Forelimbs and hindlimbs well developed; dorsal surface of forelimbs without tubercles, but dorsal surface of hindlimbs bearing tubercles; no webbing between the fingers and toes; digits moderately dilated; fingers and toes II – IV clawed; claws laterally compressed, extending beyond the terminal lamellae; LF 1 7–10; LF 4 9–12; LT 1 7–9; LT 4 9–12.

Main characters of the pattern in life.

(Fig. 7 ). In life, the coloration of the paratypes resembles that of the holotype. The dorsal surface of the body consists of 7–10 irregular dark transverse bands, which are faintly interrupted along the midline by a narrow vertebral line. Laterally, these bands are partly fragmented and partly interconnected, forming an irregular, checkerboard-like reticulated pattern across the dorsum. The dorsal surface of the tail (based only on original tail specimens) bears 11–14 relatively regular dark transverse bands, forming distinct annulations. The ventral surface of the body is uniformly creamy white, while the ventral surface of the tail is pale yellowish-white.

Main characters of the pattern in preservation.

(Fig. 8 ). In preservative, the dorsal ground color of the head, body, and limbs turns grey or greyish-white, with the yellowish-brown spots on the dorsum disappearing, while the dark brown markings remain distinct; the ventral surface fades to greyish-white.

Distribution and habitat.

Gekko tesselatus sp. nov. is currently known only from its type locality, Se’ergu Town, Heishui County, northwestern Sichuan Province, China. All individuals were collected at night from rocky slopes within a hot-dry valley covered with low shrubs and grasses, at elevations between 1,827 m and 2,047 m, where nighttime temperatures remained above 26 ° C (Fig. 9 A, B ). Field observations indicate that this species shows a strong preference for heavily weathered rock faces with abundant crevices (Fig. 9 C ). Individuals were usually hiding in crevices more than two meters above the ground, with scattered feces observed nearby. By contrast, on less weathered slopes with few crevices, individuals were rarely encountered. The highest altitude at which specimens were collected was 2,047 m, where only a single individual was found despite the high degree of rock weathering. No traces of the species were detected at higher elevations, suggesting that its actual altitudinal range may not exceed 2,100 m. The lower temperatures at higher elevations are likely unsuitable for its survival.

In addition, the species appears to be poorly adapted to anthropogenically modified environments. Although some collection sites were located close to villages, no individuals were observed around human dwellings. Within the same habitat, we also recorded Lycodon multizonatus (Zhao & Jiang, 1981) , which may represent one of the principal natural predators of Gekko tesselatus sp. nov. (Fig. 9 D ).

Comparisons.

Based on both morphological and molecular evidence, Gekko tesselatus sp. nov. is closely related to G. fengshanensis , G. kwangsiensis , G. liboensis , and G. paucituberculatus . Detailed morphological comparisons between Gekko tesselatus sp. nov. and four closest species are shown in Table 5 and Fig. 10 . Gekko tesselatus sp. nov. can be distinguished from G. fengshanensis by (1) MBSR 98–106 (vs. 149–161), (2) VS 31–39 (vs. 40–49), (3) SMC 130–157 (vs. 197–213), (4) DTR 12–15 (vs. 9–11), (5) PP 6–8 (vs. 9–12), (6) LF 1 7–10 (vs. 11–13), (7) LT 1 7–9 (vs. 12–14), and (8) LT 4 9–12 (vs. 13–15). It can be distinguished from G. kwangsiensis by (1) MBSR 98–106 (vs. 143–156), (2) VS 31–39 (vs. 41–45), (3) SMC 130–157 (vs. 185–208), (4) DTR 12–15 (vs. 9–11), (5) PP 6–8 (vs. 9–10), (6) LT 1 7–9 (vs. 11–13), (7) IOS 24–28 (vs. 29–31), and (8) LT 4 9–12 (vs. 14–18). It can be distinguished from G. liboensis by (1) MBSR 98–106 (vs. 131–140), (2) SMC 130–157 (vs. 183–195), (3) DTR 12–15 (vs. 9–10), (4) PP 6–8 (vs. 9), (5) LF 1 7–10 (vs. 12–13), (6) LF 4 9–12 (vs. 14–17), (7) LT 1 7–9 (vs. 12–13), (8) IOS 24–28 (vs. 32–35), and (9) LT 4 9–12 (vs. 14–15). Furthermore, it can be distinguished from G. paucituberculatus by (1) MBSR 98–106 (vs. 136–142), (2) VS 31–39 (vs. 42–44), (3) SMC 130–157 (vs. 189–192), (4) DTR 12–15 (vs. 4), (5) PP 6–8 (vs. 12), and (6) IOS 24–28 (vs. 37).

The main characteristics that distinguish Gekko tesselatus sp. nov. from other species of the subgenus Japonigekko are summarized in Table 6 . By having 6–8 precloacal pores in males, the new species can be easily distinguished from G. aaronbaueri Tri, Thai, Phimvohan, David & Teynié, 2015 , G. adleri Nguyen, Wang, Yang, Lehmann, Le, Ziegler & Bonkowski, 2013 , G. canhi Rösler, Nguyen, Van Doan, Ho, Nguyen & Ziegler, 2010 , G. chinensis , G. jinjiangensis Hou, Shi, Wang, Shu, Zheng, Qi, Liu, Jiang & Xie, 2021 , G. kaiyai Zhang, Wu & Zhang, 2023 , G. khunkhamensis Sitthivong, Lo, Nguyen, Ngo, Khotpathoom, Le, Ziegler & Luu, 2021 , G. liui Zhou, Zhou, Wang, Li, Zhang, Li, Shen, Liu & Rao, 2025 , G. melli , G. palmatus Boulenger, 1907 , G. prep , G. scabridus Liu & Zhou, 1982 , G. scientiadventura Rösler, Ziegler, Vu, Herrmann & Böhme, 2004 , G. sengchanthavongi Luu, Calame, Nguyen, Le & Ziegler, 2015 , G. shibatai Toda, Sengoku, Hikida & Ota, 2008 , G. similignum , G. tawaensis Okada, 1956 , G. thakhekensis Luu, Calame, Nguyen, Le, Bonkowski & Ziegler, 2014 ; G. truongi Phung & Ziegler, 2011 ; and G. vertebralis Toda, Sengoku, Hikida & Ota, 2008 (vs. 3–4 in G. aaronbaueri , 17–21 in G. adleri , 5 in G. canhi , 17–27 in G. chinensis , 4–5 in G. jinjiangensis , 9–12 in G. kaiyai , 0 in G. khunkhamensis , 20–23 in G. liui , 9–11 in G. melli , 23–30 in G. palmatus , 24 in G. prep , 10–15 in G. scabridus , 23–30 in G. scientiadventura , 4–5 in G. sengchanthavongi , 0–3 in G. shibatai , 17 in G. similignum , 0 in G. tawaensis , 1–5 in G. thakhekensis , 10–11 in G. truongi , and 0–1 in G. vertebralis ).

By having MBSR 98–106, Gekko tesselatus sp. nov. can be distinguished from G. bonkowskii Luu, Calame, Nguyen, Le & Ziegler, 2015 ; G. cib Lyu, Lin, Ren, Jiang, Zhang, Qi & Wang, 2021 ; G. hokouensis Pope, 1928 ; G. ichangensis Cao, Sucharitakul, Tie, Suwannapoom, Yan & Chomdej, 2025; G. japonicus (Duméril & Bibron, 1836) ; G. nadenensis Luu, Nguyen, Le, Bonkowski & Ziegler, 2017 ; and G. subpalmatus (Günther, 1864) (vs. 117 in G. bonkowskii , 128–149 in G. cib , 119–130 in G. hokouensis , 127–145 in G. ichangensis , 130–144 in G. japonicus , and 129–156 in G. nadenensis ).

By having DTR 12–15, Gekko tesselatus sp. nov. can be distinguished from G. auriverrucosus Zhou & Liu, 1982 , G. guishanicus Lin & Yao, 2016 , G. swinhonis , and G. wenxianensis Zhou & Wang, 2008 (vs. 16–20 in G. auriverrucosus , 0 in G. guishanicus , 6–8 in G. swinhonis , and 10 in G. wenxianensis ).

Moreover, by having LT 4 9–12, Gekko tesselatus sp. nov. can be distinguished from G. alpinus Ma, Shi, Shen, Chang & Jiang, 2024 , G. taibaiensis Song, 1985 , and G. yakuensis Matsui & Okada, 1968 (vs. 13–15 in G. alpinus , 7–8 in G. taibaiensis , and 15 in G. yakuensis ).

Figures

Figure 3. Preserved specimen of the holotype of Gekko tesselatus sp. nov. (CIB 119371, male). A. Dorsal view; B. Ventral view; C. Dorsal view of head; D. Lateral view of head; E. Ventral view of head; F. Ventral view of hand; G. Ventral view of foot; H. Dorsal view of midbody. Photographs by YHX. Scale bars: 5 mm.

Figure 4. Precloacal pores in the adult male Gekko tesselatus sp. nov. A. Specimen CIB 119371, holotype; B. Specimen QHU R 2025023, paratype; C. Specimen QHU R 2025025, paratype; D. Specimen SYS r 003029, paratype. Photographs by YHX.

Figure 5. Postcloacal tubercles in the adult male Gekko tesselatus sp. nov. A. Specimen CIB 119371, holotype; B. Specimen QHU R 2025023, paratype; C. Specimen QHU R 2025025, paratype; D. Specimen SYS r 003029, paratype. Photographs by YHX.

Figure 6. 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 YHX.

Figure 7. Coloration of Gekko tesselatus sp. nov. in life. A. Specimen QHU R 2025022, adult female; B. Specimen QHU R 2025023, adult male; C. Specimen QHU R 2025024, adult female; D. Specimen QHU R 2025025, adult male; E. Specimen QHU R 2025026, subadult male; F. Specimen SYS r 003029, adult male. Photographs by YHX.

Figure 8. Preserved specimen of the female paratype of Gekko tesselatus sp. nov. (QHU R 2025024). A. Dorsal view; B. Ventral view; C. dorsal view of head; D. Lateral view of head; E. Ventral view of head; F. Ventral view of hand; G. Ventral view of foot; H. Dorsal view of midbody. Photographs by YHX. Scale bars: 5 mm.

Figure 9. 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 YHX (A – C) and TXG (D).

Figure 10. 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).