Cyrtodactylus culaochamensis, Tri & Grismer & Thai & Jr, 2020

Tri, Ngo Van, Grismer, L. Lee, Thai, Pham Hong & Jr, P. L. Wood, 2020, A new endemic insular Bent-toed Gecko (Squamata: Gekkonidae: Cyrtodctylus) from Quang Nam Province, Central Vietnam, Zootaxa 4766 (2), pp. 389-400 : 392-399

Cyrtodactylus culaochamensis sp. nov.

Figs.1 , 2

Holotype. ITBCZ 2494 , adult male collected by Ngo Van Tri (N.V. T) at 20:30 on 15 February 2014 on the surface of a large rock along a small stream in Hon Lao Island , Cu Lao Cham Biosphere Reserve , Tân Hi ệp Commune , Hoi An City, Quang Nam Province, Central Vietnam (around of 15 º 57’N, 108 º 30’E) at 50 m above sea level.

Paratypes. The paratypes ITBCZ 2495, 2497–98 bear the collection data as the holotype. Paratype ITBCZ 2496 was collected by Phạm Hồng Thái (P.H.T.) at the same locality but on 17 February 2014.

Diagnosis. Cyrtodactylus culaochamensis sp. nov. differs from all other congeners by the following combination of characters: maximum SVL 79.8 mm (n=5); original tail length (TL/SVL:1.14–1.31); dark spots and blotches on head edged in lighter coloration; nuchal loop usually fragmented; five or six irregularly shaped, dark, broad, broken dorsal bands; original tail bearing 10–13 dark-brown alternating rings; 2–5 intersupranasals; 11–13 supralabials; nine or 10 infralabials; seven or eight precloacal pores in males; no precloacal pores in females; no enlarged scales beneath thighs; 19–21 interorbitals; 28–32 scales between eyeball and nostril; 45–50 rows of ventral scales; 20–22 irregular, longitudinal rows of smooth and weakly keeled midbody tubercles; 27–32 paravertebral tubercles between limb insertions; 13–15 subdigital lamellae on first toe; 20–23 subdigital lamellae on fourth toe; and slightly enlarged subcaudal scales.

Description of holotype ( Fig. 1A ). Adult male, SVL 77.4mm. Head moderately long (HeadL/SVL:0.27), relatively narrow (HeadW/HeadL:0.67), depressed (HeadH/HeadL: 0.34), distinct from neck; lores and interorbital region inflated, canthus rostralis absent, frontonasal region concave; snout elongate (SnEye/HeadL: 0.37), pointed, longer than eye diameter (OrbD/SnEye: 0.68); scales on snout small, rounded, granular, homogeneous, larger than those on occipital region. Eye large (OrbD/HeadL:0.26), iris chestnut with red crenelated pupilar margins; supraciliaries short, bearing tiny conical spines posteriorly. Ear opening oval, oblique, small (EarL/HeadL: 0.10); eye to ear distance greater than diameter of eye (EyeEar/OrbD: 1.02). Rostral scale smooth, wider (2.3 mm) than high (1.5 mm), incompletely divided posteriorly by a shallow Y-shaped dorsal groove; two enlarged supranasals separated by one large intersupranasal; rostral in contact with first supralabial and nostril; nostril oval, surrounded by supranasal, rostral, first supralabial, and three enlarged postnasals; three or four rows of small scales separate orbit from supral- abials. Mental triangular, wider (2.7mm) than deep (1.6mm); one pair of enlarged postmentals, in broad contact medially, bordered laterally by first infralabial and first chinshield, posterolaterally by four small gular scales. Thirteen supralabials and 10 infralabials on each side; 20 interorbital scale rows; 32 scales between eye and nostril.

Body slender, elongate (TrunkL/SVL: 0.42). Dorsal scales conical; regularly distributed weakly keeled tubercles (4–6 times size of adjacent scales), extend from occiput to base of tail; tubercles arranged in 22 irregular rows at midbody, smallest on flanks and in occipital region; 27 paravertebral tubercles. Ventral scales larger than dorsals, smooth, relatively round, subimbricate, largest posteriorly; 50 ventral scale rows with smooth tubercles in scattering on lateral folds; gular region bearing relatively homogeneous, smooth scales. Precloacal groove absent; precloacal scales enlarged; a series of seven precloacal pores in a chevron pattern; no enlarged femoral scales beneath each thigh. Scales on palm and hind limbs granular with scattered, weakly keeled tubercles that are smaller than those on dorsum.

Fore and hind limbs moderately slender (ForeL/SVL: 0.14; CrusL/SVL: 0.16); digits moderately slender, strongly inflected at basal interphalangeal joints, all bearing slightly curved claws; basal subdigital lamellae nearly as broad as digit and lacking a scansorial surface: 5–6–7–7–7 manus; 5–8–8–9–9 pes; narrow lamellae distal to digital inflection and not including ventral claw sheath: 8–7–10–10–7 manus; 7–9–12–12–11 pes; one or two rows of small, non-lamellar granules between basal and distal lamellar series; interdigital webbing present but weakly developed. Length of digits in mm: (manus)III (6.9)>IV (6.0)> II (4.7)> V (4.5)>I (3.6); (pes):IV (7.3)> V (7.2)> III (7.2)> II (5.8)> I (3.7).

Original tail length 90.7 mm (TL/SVL: 1.27), slender, tapering to a point; longer than SVL; two smooth, whitish postcloacal tubercles at base; base of tail bearing five parasagittal and three longitudinal rows of keeled tubercles, followed by two rows of smaller tubercles on the first four segments of tail, decreasing to one row towards the posterior segment and absent posteriorly to that; subcaudals smooth, subimbricate, all subcaudals very slightly enlarged throughout length of tail.

Coloration in life ( Fig. 2 ). Top of head brown with dark blotches or spots edged in lighter coloration; chestnut iris with crenelated vertical pupil, eye rings yellowish; nuchal loop fragmented; two irregularly shaped, dark bands anterior to forelimb insertions that grade into four broken bands posteriorly that resemble transversely arranged, squarish blotches; small dark blotches scattered on flanks; dorsal surface of limbs brown, bearing irregularly shaped darker bands; all dark markings on body and limbs are edged with light-colored tubercles; original tail bearing 10 dark and light-brown alternating rings. Ventral surface of body pinkish bearing scattered yellowish spots.

Variation ( Fig. 2 ). Color pattern of the paratypes resembles that of the holotype. ITBCZ 2496 bears a complete, thin, dark nuchal loop and the first dorsal body band is U-shaped. ITBCZ 2498 has a portion of regenerated tail is brown, scattered with small dark spots. ITBCZ 2494, showing light, subcaudal rings. Variation in scale counts is presented in Table 1 .

Etymology. The specific epithet is derived from the name of Cu Lao Cham Mountain in Cu Lao Cham Biosphere Reserve. Suggested common names: English: Cù Lao Chàm Bent–toed Gecko; Vietnamese: Thằn lằn chân ngón Cù Lao Chàm.

Distribution and Natural History. Cyrtodactylus culaochamensis sp. nov. is currently known only from Hon Lao Island of Cu Lao Cham Biosphere Reserve, Hoi An Town in Quang Nam City, Central Vietnam. All specimens were collected at night on rock outcrops composed of large granitic boulders along a small, permanently flowing stream. Other specimens were observed on tree branches and dry tree roots beneath the canopy, 0.3 m– 1.5 m above forest floor during the rainy season. ITBCZ 2259–2260 were collected by local people in Cu Lao Cham Islands during April of 2009. These specimens were put into 40% alcohol and became severely degraded and were not included in the type series.

Comparisons. Cyrtodactylus culaochamensis sp. nov. differs from the other members in its clade ( Fig. 1 ) as outlined below. From Cyrtodactylus culaochamensis sp. nov. differs from C. badenensis Hguyen, Orlov, & Darevsky , C. condorensis (Smith) , C. leegrismeri Chan & Norhayati , C. eisenmanae Ngo , and C. grismeri Ngo by the absence as opposed to the presence of enlarged femoral scales. It differs from C. irregularis (Smith) by having 20–20 longitudinal rows of body tubercles as opposed to 17. It differs from C. yangbayensis Ngo & Chan by having a smaller maximum SVL of 79.8 mm versus 109.1 mm. longitudinal rows of body tubercles as opposed to 17. Cyrtodactylus culaochamensis sp. nov. differs from C. dati Ngo by having seven or eight precloacal pores as opposed to five or six and no femoral prores as opposed to six or seven. Cyrtodactylus culaochamensis sp. nov. is most closely related to C. pseudoquadrivirgatus Rösler, Nguyen, Vu, Ngo & Ziegler from which it differs by having all the subcaudals being only slightly enlarged at best ( Fig. 4A ) versus having two medial rows of distinctly enlarged subcaudals (Rösler et al. 2008; Fig. 2D ). These two species differ by an uncorrected pairwise sequence divergence of 7.2%.

Figures

FIGURE 1. Inferred phylogenetic relationships Cyrtodactylus culaochamensis sp. nov. The tree is a maximum likelihood topology with BPP and ML nodal support, respectively.

FIGURE 2. Cyrtodactylus culaochamensis sp. nov. A: Holotype ITBCZ 2494; B: paratype ITBCZ 2495 showing the irregularly shaped dorsal bands and blotches; C: paratype ITBCZ 2498 showing the thin nuchal loop and full tail with 13 light-colored bands alternating with dark-brown bands.

FIGURE 4. A: Ventral view of tail of Cyrtodactylus culaochamensis sp. nov., ITBCZ 2494, showing light-colored, subcaudal rings and very slightly enlarged subcaudals; B: Precloacal region of C. culaochamensis sp. nov ITBCZ 2494, showing seven precloacal cloacal pores in a chevron pattern.