Cyrtodactylus hontreensis, Tri & Grismer & Grismer, 2008

Tri, Ngo Van, Grismer, L. Lee & Grismer, Jesse L., 2008, A new endemic cave dwelling species of Cyrtodactylus Gray, 1827 (Squamata: Gekkonidae) in Kien Giang Biosphere Reserve, Southwestern Vietnam, Zootaxa 1967, pp. 53-62 : 54-60

Cyrtodactylus hontreensis sp. nov.

Figures 1–2

Suggested common name. English: Hon Tre Bent-toed Gecko and Vietnamese: Thǎn Lǎn Chân Ngón Hòn Tre.

Holotype. UNS 0216 , an adult male collected by Ngo Van Tri on Hon Tre Island , Kien Hai District, Kien Giang Biosphere Reserve, Kien Giang province, southwestern Vietnam (09°57.922’N 104°50.678’E) on 2 September 2006, at approximately 100 m a.s.l.

Paratypes. UNS 0217–22 , consist of 3 adult females, 2 adult males and 1 subadult male collected by Ngo Van Tri on the same place on 6 January 2006, at approximately 15 m a.s.l.

Diagnosis. Cyrtodactylus hontreensis sp. nov. differs from all congeners by the combination of the following characteristics: body slender; SVL 79.7 ± 4.9 mm; occiput without spots or bands; 16 or 17 scales across rostrum; 21–26 scales between eye and nostril; three broad dorsal body bands edged in white between limb insertions; no precloacal groove; seven or eight precloacal pores in males; 2–5 enlarged femoral scales; 40–42 ventral scales between ventrolateral body folds; very low, smooth body tubercles in fourteen irregular longitudinal rows at midbody; 20–24 paravertebral tubercles; 21–22 subdigital lamellae on first toe; 17–19 subdigital lamellae on fourth toe; tail segmented, a shallow middorsal groove present, caudal tubercles; broad dark band at base of tail; enlarged subcaudal scales.

Description of holotype. Adult male, SVL 88.9 mm. Head moderately long (HeadL/SVL = 0.28), relatively narrow (HeadW/HeadL = 0.64), depressed (HeadH/HeadL = 0.38), distinct from neck. Loreal and interorbital region inflated, canthus rostralis not prominent, frontonasal region concave. Snout elongate (SnEye/ HeadL = 0.40), relatively pointed; longer than eye diameter (OrbD/SnEye = 0.65); scales on snout and pre- frontal region small, rounded, granular, homogeneous; scales on snout larger than those on occiput. Eye large (OrbD/HeadL = 0.26); pupil vertical with crenellate margins when closed, round when maximally open; supraciliaries short, bearing tiny conical spines posteriorly. Ear opening oval, small (EarL/HeadL = 0.09); eye-to-ear distance smaller than diameter of eye (EyeEar/OrbD = 0.98). Rostral incompletely divided by shallow inverted Y-shaped groove; two enlarged supranasals separated by an postrostral; postrostral larger than supranasals, in contact posteriorly with two enlarged scales on rostrum; rostral in contact with first supralabial and nostril; nostril oval, surrounded by supranasal, rostral, first supralabial, and two enlarged postnasals; 2–4 rows of small scales between orbit and supralabials. Mental triangular, wider (3.5 mm) than long (2.5 mm); one pair of enlarged postmentals contacting medially posterior to mental, bordered laterally by first infralabials and one half of second infralabials, followed posterolaterally by three (R) and two (L) enlarged chinshields. 10 (R) and 8 (L) supralabials terminating at middle of orbit; total number of supralabials to angle of jaws 11 (R), 10 (L); infralabials 10 (R), 11 (L); 17 interorbital scale rows across narrowest point of frontal; 26 scales between eye and nostril.

Body slender, elongate (TrunkL/SVL = 0.43), with ventrolateral folds. Dorsal scales granular to weakly conical; regularly distributed conical tubercles (1-1.5 times size of adjacent scales) extending from nuchal region to tail base; tubercles in approximately 14 irregular rows at midbody, smallest on flanks, and nuchal region; 22 paravertebral tubercles. Ventral scales much larger than dorsal, smooth, relatively round, subimbricate, largest posteriorly; 42 rows of ventral at midbody; gular region with relatively homogeneous, smooth scales. No precloacal groove, seven enlarged precloacal scales bearing pores in chevron pattern, four enlarged scales anterior to vent, three enlarged femoral scales beneath right thigh, two beneath left thigh, discontinuous with enlarged precloacal scales; plantar scales and scales on hind limbs granular with one or two weakly keeled tubercles on lower part of each knee, a row of 4 or 5 enlarged scales on each heel.

Forelimbs and hind limbs slender (ForeL/SVL = 0.16; CrusL/SVL = 0.18); digits moderately short, strongly inflected at basal interphalangeal joints, all bearing slightly curved claws; basal subdigital lamellae nearly as broad as digit, phalangeal pattern 8-8-8-7-8 for manus, 9-10-9-8-7 for pes; narrow lamellae distal to digital inflection and not including ventral claw sheath: 10-9-10-9-11 for manus; 12-11-10-11-9 for pes; one or two rows of small, non-lamellar granules between basal and distal lamellar series; interdigital webbing present but weakly developed. Relative length of digits (mm) on manus: III (6.5)> II (6.3)> IV (6.1)> V (5.6)> I (4.0); (pes): II (7.9)> I (7.6)> III (7.3)> IV (6.3)> V (4.2).

Original tail long (TailL/SVL = 1.19), posterior one third regenerated, expanded at tail base with shallow middorsal longitudinal groove, tapering to tip; three white, smooth postcloacal tubercles on each side. Twenty caudal segments in two-thirds of original tail with nine scales/segment. Six parasagittal rows of large conical dorsal, caudal tubercles continuing from body; subcaudals smooth, subimbricate, juxtaposed, relatively large, extending length of tail; dorsal caudal scales flat, hexagonal or pentagonal.

Coloration in life. Head brown with two yellowish preorbital stripes on snout; yellow eye ring; a broad dark brown nuchal loop edged in white; three brown dorsal bands between limb insertions, edged in white, with diffuse dark spots in the interspaces; one dark band on tail base edged in white anteriorly; original tail brown, tinged with dark brown blotches laterally on each segment, short regenerated portion of tail with faint brownish blotches; pinkish-brown fore- and hind limbs tinged with yellow dorsally. Venter pinkish-white.

Variation. Differences in the number of enlarged femoral scales beneath the thighs are as follows: UNS 0217 : 3( R)–5(L), UNS 0218 : 4( R)–5(L), UNS 0219 : 2 ( R)–3(L), UNS 0220 : 1( R) - 3(L), UNS 0221 : 4 ( R) - 5(L), UNS 0222 : 2( R)–3(L). Differences in the size of the intersupranasal scales in comparison with supranasal scales are: UNS 0217 : smaller, UNS 0218 : larger, UNS 0219 : larger, UNS 0220 : larger, UNS 0221 : smaller, UNS 0222 : smaller. Additional variation in meristic and mensural characteristics is presented in Table 1. There is no variation of color pattern in the type series. The coloration fades in alcohol .

Etymology. The specific epithet hontreensis is in reference to the type locality.

Distribution and natural history. Hon Tre Island ( Figure 3) is approximately 30 km south of Rach Gia City ( Figure 4). Six voucher specimens (paratypes UNS 0217–22) were collected by NVT on 6 January 2006 in a 10 m deep rocky cave at approximately of 15 m a.s.l. The holotype UNS 0216 was also collected by NVT in another 7 m deep cave on 2 September 2006, at approximately 100 m a.s.l. These cave systems were formed by soil erosion surrounding granitic boulders piled on top of one another above small, permanent streams. Other species of geckos from the same habitat are Cnemaspis caudanivea Grismer & Ngo , Gekko gecko (Linnaeus) , Hemidactylus platyurus (Schneider) , Gehyra mutilata (Wiegmann) , Hemidactylus frenatus Duméril & Bibron , and Cyrtodactylus sp.

Comparison with other species. Cyrtodactylus hontreensis sp. nov. is most similar to the other Cavedwelling Cyrtodactylus in Vietnam but can be separated from them by basic characteristics in Table 2.

Table 2. Comparison among cave-dwelling (Ngo 2008).? = Character state could not be determined from literature (see Rösler & Glaw 2008).