Cyrtodactylus chuyangsinensis, Nguyen & Nguyen & Nguyen & Ha & Le & Grismer & Luu, 2025

Cyrtodactylus chuyangsinensis sp. nov.

Chuyangsin Bent–toed Gecko

Figs 7–8 View FIGURE 7 View FIGURE 8 .

Material examined. Holotype. Adult male, VNUF R. 2025.12 ( Field No. DakLak 02) near Ðak Tuôr waterfall, Cu Pui Commune , Krong Bong district , Dak Lak Province within Chu Yang Sin National Park , ( 12°28'59.9"N, 108°28'08.5"E; 582 m a.s.l.), collected by Vinh Quang Luu, Sang Van Le, and Hien Phuong Nguyen on 28 October 2023. GoogleMaps

Paratypes. Adult male VNUF R. 2025.11 ( Field No. DakLak 01), adult male VNUF R. 2025.13 ( Field No. DakLak 03), adult female VNUF R. 2025.14 ( Field No. DakLak 04), adult female VNUF R. 2025.15 ( Field No. DakLak 05), adult female VNUF R. 2025.16 ( Field No. DakLak 06), and adult female VNUF R. 2025.17 ( Field No. DakLak 07) bear the same data as the holotype GoogleMaps .

Diagnosis. Cyrtodactylus chuyangsinensis sp. nov. can be distinguished from all congeners of Cyrtodactylus on the basis of the following combination of characters: A maximum SVL of 92.3 mm; supralabials 10–12; infralabials 8–10; longitudinal dorsal tubercle rows at midbody in 12–15; ventral scales 38–48; subdigital lamellae on fourth toe 17–23; precloacal pores 7–8 in males and 0–6 on females; enlarged precloacal scales 19–24; enlarged femoral scales on each thigh 6–9; enlarged subcaudals lacking; dorsal head and body surface coloration light-brown; small, irregularly shaped dark-brown blotches on top of head; a slender, dark-colored nuchal loop with a concave anterior border and convex posterior border extending from the nape to the posterior margins of the orbits; dark-colored dorsal bands divided into paravertebral elements.

Description of the holotype. Adult male, SVL 72.6 mm; head distinct from neck, relatively long (HL/SVL 0.29), moderately widened (HW/HL 0.68), and depressed (HD/HL 0.37); one intersupranasal scale, separated from each supranasal; snout long, blunt in dorsal profile (SE/HL 0.40), longer than orbit diameter (OD/SE 0.58); scales on snout small, round or oval, granular, lager than scales on occiput; orbit large (OD/HL 0.23); pupils vertical; ear opening small, oval (EarL/HL 0.07); eye to ear distance longer than orbit diameter (Eye Ear/OD 1.16); rostral wider than high (RW/RH 1.73), partially divided dorsally with a straight median suture extending to the centre of the scales, in contact with first supralabial, naris and two intersupranasals; mental scale triangular, wider than high (ML/MW 0.77); two enlarged, triangular postmentals; supralabials 10/11; infralabials 9/8.

Body relatively short (AG/SVL 0.39); 15 dorsal tubercles round, keeled and each surrounded by nine granular scales; ventral scales larger than dorsals, smooth, oval, subimbricate, largest posteriorly, in 48 scale rows at midbody; 124 scale rows encircle midbody; enlarged precloacal scales 19, arranged in a chevron shape; precloacal pores 7; femoral pores absent; enlarged femoral scales nine on each thigh.

Forelimbs and hindlimbs moderately slender (ForeaL/SVL 0.13 mm, CrusL/SVL 0.21); dorsal surface of forelimbs and hindlimbs bearing well-developed tubercles; two postcloacal tubercles on each side of the hemipenal; number of subdigital lamellae on first finger 11/11, on first toe 12/13, on fourth finger 18/17, on fourth toe 20/19. Tail original, 82.0 mm in length, 6.7 mm in width at base; dorsal tail base with distinct tubercles; enlarged subcaudals absent.

Coloration in life. Dorsal surface of head, body and limbs light-brown; top of head bearing irregularly shaped dark-brown blotches; a slender, dark-colored nuchal loop with a concave anterior border and convex posterior border extends from the neck to the posterior margins of orbits; dark-colored dorsal body bands composed of paravertebral elements; dark-colored dorsal body bands narrower than pale dorsal interspaces and irregularly shaped; pale interspaces bearing dark-colored markings; pale tubercles irregularly scattered along flanks; dorsal surface of limbs with alternating light-brown and dark-brown bands; upper side of tail with eight dark-brown bands which are wider than the pale bands; ventral surface of head, body, and limbs beige to cream; and ventral surface of tail greyish brown.

bugiamapensis

** = broken.

Variation. The paratypes closely resemble the holotype, except the following differences: precloacal pores absent in females VNUF R. 2025.15 and VNUF R. 2025.16; and two intersupranasals in females VNUF R. 2025.14 and VNUF R. 2025.16. For more details in meristic and mensural variations see Tables 5, 6, and for color pattern variation see Figs. 7 View FIGURE 7 , 8 View FIGURE 8 .

Comparisons. Cyrtodactylus chuyangsinensis sp. nov. can be distinguished from its closest relatives, which consist of C. phnomchiensis ( Nazarov, Poyarkov, Orlov, Phung, Nguyen, Hoang & Ziegler, 2012) , C. ziegleri, (Nazarov, Orlov, Nguyen & Cuc, 2008) , and C. bugiamapensis ( Nazarov, Poyarkov, Orlov, Phung, Nguyen, Hoang & Ziegler, 2012) , and all other species of the C. irregularis group in Vietnam based on morphological characters presented in Table 7.

Cyrtodactylus chuyangsinensis sp. nov. is genetically most closely to the C. ziegleri , C. phnomchiensis , and C. bugiamapensis . However, it differs from C. ziegleri by having more ventral scale rows (38–48 versus 33–39 in C. ziegleri ), fewer enlarged femoral scales (6–9 versus 8–10 in C. ziegleri ), the absence of femoral pores in males ( versus 0–6 in C. ziegleri ); from C. phnomchiensis by having a larger tail length (82.0– 99.9 mm versus 56.9–79.1 mm in C. phnomchiensis ), and more precloacal pores in males (7–8 versus 4–5 in C. phnomchiensis ); from C. bugiamapensis by having more a larger size (SVL 75.8–92.3 mm versus 58.6–76.8 mm in C. bugiamapensis ), more lamellae under the fourth finger (16–21 versus 15–17 in C. bugiamapensis ), and different dorsal color pattern (banded versus blotched in C. bugiamapensis ).

Cyrtodactylus chuyangsinensis sp. nov. from Dak Lak can be distinguished from other species in C. irregularis group as follows: from C. arndti by having the absence of femoral pores in males ( versus 0–2 in C. arndti ), and the absence of transversely enlarged subcaudal plates ( versus present in C. arndti ); from C. ayunpaensis by having fewer ventral scale rows (38–48 versus 52–68 in C. ayunpaeneis ), the presence of precloacal pores in males (7–8 versus absent in C. ayunpaeneis ), and the absence of transversely enlarged subcaudal plates ( versus present in C. ayunpaeneis ); from C. badenensis by having a larger size (SVL 75.8–92.3 mm versus 59.3–74.1 mm in C. badenensis ), more ventral scale rows (38–48 versus 25–29 in C. badenensis ), the presence of enlarged femoral scales (6–9 versus absent in C. badenensis ), and the presence of precloacal pores in males (7–8 versus absent in C. badenensis ); C. bidoupimontis by having fewer enlarged femoral scales (6–9 versus 8–10 in C. bidoupimontis ), more precloacal pores in males (7–8 versus 4–6 in C. bidoupimontis ), and the presense of precloacal pores in females (0–6 versus absent in C. bidoupimontis ); from C. caovansungi by having smaller tail length ( 85.8–99.9 mm versus 120 mm in C. caovansungi ), the absence of femoral pores in males ( versus 6 in C. caovansungi ), fewer precloacal pores in males (7–8 versus 9 in C. caovansungi ), fewer lamellae under the fourth finger and fourth toe (16–21, 17–23 versus 22, 23–25 in C. caovansungi , respectively), and the absence of transversely enlarged subcaudal plates ( versus present in C. caovansungi ); from C. cattienensis by having a larger size (SVL 75.8–92.3 mm versus 43.5–69.0 mm in C. cattienensis ), larger tail length ( 85.8–99.9 mm versus 51.0– 64.7 mm in C. cattienensis ), the presence of precloacal pores in females (0–6 versus absent in C. cattienensis ), and more lamellae under the fourth finger (16–21 versus 12–16 in C. cattienensis ); from C. chumuensis by having a larger size (SVL 75.8–92.3 mm versus 52.4–67.5 mm in C. chumuensis ), more enlarged femoral scales (6–9 versus 4–5 in C. chumuensis ), and the absence of femoral pores in males ( versus 0–2 in C. chumuensis ); from C. chungi by having larger size (SVL 75.8–92.3 mm versus 66.6–68.5 mm in C. chungi ), more ventral scale rows (38–48 versus 30–31 in C. chungi ), and more enlarged femoral scales (6–9 versus 4–6 in C. chungi ); from C. cryptus by having fewer ventral scale rows (38–48 versus 47–50 in C. cryptus ), the presence of enlarged femoral scales (6–9 versus absent in C. cryptus ), fewer precloacal pores in males (7–8 versus 9–11 in C. cryptus ), and the presence of precloacal pores in females (0–6 versus absent in C. cryptus ); from C. cucdongensis by having larger size (SVL 75.8–92.3 mm versus 55.8–65.9 mm in C. cucdongenis ), more precloacal pores in males (7–8 versus 5–6 in C. cucdongensis ), and more supralabial scales (10–12 versus 8–10 in C. cucdongensis ); from C. culaochamensis by having the presence of enlarged femoral scales (6–9 versus absent in C. culaochamensis ), and the presence of precloacal pores in females (0–6 versus absent in C. culaochamensis ); from C. dati by having larger size (SVL 75.8–92.3 mm versus max 70.1 mm in C. dati ), more enlarged femoral scales (6–9 versus 4–7 in C. dati ), the absence of femoral pores in males ( versus 3–4 in C. dati ), more precloacal pores in males (7–8 versus 5–6 in C. dati ), and different dorsal color pattern (banded versus blotched in C. dati ); from C. gialaiensis by having a larger size (SVL 75.8–92.3 mm versus 50.1–62.8 mm in C. gialaiensis ), the presence of enlarged femoral scales (6–9 versus absent in C. gialaiensis ), fewer precloacal pores in males (7–8 versus 9–10 in C. gialaiensis ), and more lamellae under the fourth finger and fourth toe (16–21, 17–23 versus 14–15, 15–17 in C. gialaiensis , respectively); from C. huynhi by having a larger size (SVL 75.8–92.3 mm versus 67.2–79.8 mm in C. huynhi ), more enlarged femoral scales (6–9 versus 3–5 in C. huynhi ), and the absence of femoral pores in males ( versus 3–8 in C. huynhi ); from C. irregularis by having more precloacal pores in males (7–8 versus 5–7 in C. irregularis ), more lamellae under the fourth finger and fourth toe (16–21, 17–23 versus 15–16, 18–19 in C. irregularis ), and different dorsal color pattern (banded versus blotched in C. irregularis ); from C. kingsadai by having smaller tail length ( 85.8–99.9 mm versus max 117.0 mm in C. kingsadai ), fewer enlarged femoral scales (6– 9 versus 9–12 in C. kingsadai ), the absence of femoral pores in males ( versus 0–4 in C. kingsadai ), and the absence of transversely enlarged subcaudal plates ( versus present in C. kingsadai ); from C. orlovi by having larger size (SVL 75.8–92.3 mm versus 61.0– 77.7 mm in C. orlovi ), more ventral scale rows (38–48 versus 36–39 in C. orlovi ), more precloacal pores in males (7–8 versus 5–6 in C. orlovi ), and the presence of precloacal pores in females (0–6 versus absent in C. orlovi ); from C. phumyensis by having larger size (SVL 75.8–92.3 mm versus 63.6–66.8 mm in C. phumyensis ), and more precloacal pores in males (7–8 versus 5–7 in C. phumyensis ); from C. phuocbinhensis by having larger size (SVL 75.8–92.3 mm versus 46.0– 60.4 mm in C. phuocbinhensis ), more enlarged femoral scales (6–9 versus 5 in C. phuocbinhensis ), and the presnece of precloacal pores in females (0–6 versus absent in C. phuocbinhensis ); from C. pseudoquadrivirgatus by the presence of enlarged femoral scales (6–9 versus absent in C. pseudoquadrivirgatus ), fewer precloacal pores in females (0–6 versus 5–10 in C. pseudoquadrivirgatus ), and different dorsal color pattern (banded versus blotched in C. pseudoquadrivirgatus ); from C. raglai by having more ventral scale rows (38–48 versus 36–39 in C. raglai ), fewer enlarged femoral scales (6–9 versus 9–10 in C. raglai ), more precloacal pores in males (7–8 versus 5 in C. raglai ), and the absence of transversely enlarged subcaudal plates ( versus present in C. raglai ); from C. sangi by having larger size (SVL 75.8–92.3 mm versus 49.9–56.3 mm in C. sangi ), more ventral scale rows (38–48 versus 37 in C. sangi ), and more enlarged femoral scales (6–9 versus 4 in C. sangi ); from C. takouensis by having more enlarged femoral scales (6–9 versus 3–5 in C. takouensis ), the absence of femoral pores in males ( versus 0–2 in C. takouensis ), more precloacal pores in males (7–8 versus 3–4 in C. takouensis ), and the absence of transversely enlarged subcaudal plates ( versus present in C. takouensis ); from C. taynguyenensis by having the presence of enlarged femoral scales (6–9 versus absent in C. taynguyenensis ), more precloacal pores in males (7–8 versus 6 in C. taynguyenensis ), and different dorsal color pattern (banded versus blotched in C. taynguyenensis ); from C. yangbayensis by having the absence of femoral pores in males ( versus 0–2 in C. yangbayensis ), the presence of precloacal pores in females (0–6 versus absent in C. yangbayensis ), more lamellae under the fourth toe (17–23 versus 15–17 in C. yangbayensis ), and the absence of transversely enlarged subcaudal plates ( versus present in C. yangbayensis ).

Distribution. Cyrtodactylus chuyangsinensis sp. nov. is currently known only from the Chu Yang Sin National Park, Cu Pui Commune, Krong Bong District, Dak Lak Province ( Fig 9 View FIGURE 9 ).

Natural history. The specimens were found at night from 18:30–21:00 on stacked granite rocks and cliffs approximately 1.0–3.0 m above the ground at an elevation of approximately 581 m a.s.l. near a waterfall for tourism activities. The surrounding habitat was secondary natural evergreen forest ( Fig. 10 View FIGURE 10 ).

Etymology. This new species is named after Chu Yang Sin National Park, its type locality where it was discovered.