Cyrtodactylus saiyok, Panitvong, Nonn, Sumontha, Montri, Tunprasert, Jitthep & Pauwels, Olivier S. G., 2014

Panitvong, Nonn, Sumontha, Montri, Tunprasert, Jitthep & Pauwels, Olivier S. G., 2014, Cyrtodactylus saiyok sp. nov., a new dry evergreen forest-dwelling Bent-toed Gecko (Squamata: Gekkonidae) from Kanchanaburi Province, western Thailand, Zootaxa 3869 (1) : -

Cyrtodactylus saiyok sp. nov.

( Figs 1–4 )

Holotype. THNHM 25602 (field no. MS 457); adult male from Moo (= village) 3 (14o 12.186’ N, 0 99o 01.471’ E, 354 m asl), Tumbon (= sub-district) Wang Krajae, Amphoe (= District) Sai Yok, Kanchanaburi Province, western Thailand; collected by Jitthep Tunprasert on 17 August 2012.

Paratypes. CUMZ-R-0.2320 (field no. MS 458); subadult male, same collector and locality as holotype.

Diagnosis. Cyrtodactylus saiyok sp. nov. can be distinguished from all other congeneric species by its maximal known SVL of 61.0 mm; 18 or 19 regular longitudinal rows of dorsal tubercles; 23 or 24 longitudinal rows of ventrals across the abdomen between the non-denticulate ventrolateral skin folds; a continuous series of enlarged femoro-precloacal scales, including a continuous series of five pore-bearing precloacal scales (males); no precloacal groove or depression; 16 or 17 subdigital lamellae of 4th toe, transversely enlarged subcaudal scales; complete nuchal loop; dorsal pattern including 3-5 irregular, medially interrupted or not, black dorsal bands between the limbs. Description of holotype. Adult male. SVL 61.0 mm. TailL 67.5 mm (original). Head long (HeadL/SVL 0.30), moderately narrow (HeadW/HeadL 0.56), not markedly depressed (HeadH/HeadL 0.35), distinct from slender neck. Loreal region weakly inflated, canthus rostralis rounded. Snout moderate in length (SnOrb/HeadL 0.35), rounded, longer than orbit diameter (OrbD/SnOrb 0.67); scales on snout small, rounded to oval, granular to weakly conical, mostly homogeneous, larger than those on crown, interorbital and occipital regions. Eye moderately large (OrbD/HeadL 0.24); pupil vertical with crenelated margins; supraciliaries short. Ear opening oblique, elliptical, small (EarL/HeadL 0.04); eye to ear distance greater than orbit diameter (OrbEar/OrbD 1.23). Rostral wider (2.9 mm) than deep (2.1 mm); rostral crease nearly half of rostral height. Two enlarged supranasals separated from each other by one internasal. Rostral in contact with first supralabials, nostrils, supranasals and internasal. Nostrils oval, more-or-less laterally directed, each surrounded by supranasal, rostral, first supralabial and two enlarged postnasals. Two or three rows of small scales separate orbit from supralabials.

Mental triangular, wider (2.3 mm) than deep (1.6 mm). A single pair of greatly enlarged postmentals in broad contact, each postmental bordered anteromedially by mental, anterolaterally by first infralabial, posterolaterally by an enlarged lateral chinshield, and posteriorly by two granules. Supralabials to midorbital position 7/7, enlarged supralabials to angle of jaws 9/10. Infralabials 9/9. Interorbital scale rows across narrowest point of frontal bone 15. Gular region with homogeneous, smooth, juxtaposed granular scales.

Body slender, elongate (AG/SVL 0.48) with well-defined, non-denticulate ventrolateral folds. Dorsal scales weakly heterogeneous, domed to slightly conical; regularly distributed tubercles (about four times size of adjacent scales), extending from shoulder region onto tail base, smaller tubercles on postocular region, crown, occiput and nape; most tubercles bearing a keel, those on flanks conical, often lacking a distinct keel, those on posterior trunk and sacral region most prominent; tubercles in 19 regular rows at midbody, typically separated from one another by two or three dorsal granules. Ventral scales larger than dorsals, smooth, oval and subimbricate, largest on posterior abdomen and in precloacal region. Midbody scale rows across belly between ventrolateral folds 23. Five precloacal pores in a continuous inverted V-shaped series. No precloacal groove nor depression. A continuous row of enlarged femoral scales, showing no pores nor pits, approximately twice the size of adjacent anterior femoral scales, extends along the length of the femur and is continuous with the precloacal pore-bearing scales series. Postcloacal spurs each bearing two slightly enlarged, smooth scales.

Scales on palm and sole smooth, rounded to oval or hexagonal, slightly domed. Scalation on dorsal surfaces of limbs similar to dorsum of body, with enlarged, conical tubercles interspersed among smaller scales. Fore and hind limbs moderately long, slender (ForeaL/SVL 0.14, TibiaL/SVL 0.17). Digits long, slender, inflected at interphalangeal joints, all bearing robust, slightly recurved claws. Basal subdigital lamellae broad, oval to rectangular, lacking scansorial surfaces; lamellae distal to digital inflection narrow; 6+10 / 7+9 subdigital lamellae under 4th toe (not including ventral claw sheath); no interdigital webbing. Relative length of digits: IV>III>II>V>I (manus); IV>III>V>II>I (pes). Tail original, gently tapering to pointed tip, longer than SVL (TailL/SVL 1.11). Tail with enlarged subcaudal plates.

Coloration in life. Dorsal ground color of head, body, limbs and tail light brownish gray. Skin above orbits bluish. Complete black nuchal loop, from the posterior end of one orbit to the other, edged anteriorly and posteriorly by a thin whitish stripe. Faint, brown, wide preorbital stripe bordered dorsally by a thin, whitish stripe. One W-shaped dark brown band above shoulders, edged anteriorly and posteriorly by a thin whitish line. Three unbroken black bands on dorsum between limb insertions, partly edged with a whitish stripe, not reaching lower flanks. Two black spots above hind limb insertions. A few irregular faint brown spots on lower flanks. Tail with seven black bands, not edged with a whitish line, not continuing on under surface of tail. Ventral surfaces of head, limbs, belly and tail uniformly whitish.

Variation. Morphometric and meristic values for the type series are provided in Table 1 . Morphological and coloration characters of the paratype agree in most respects with those of the holotype, differing only in minor details. In the paratype, rostral crease half of rostral height, supralabials to midorbital position 8/7, right postmental bordered posteriorly by three granules, supranasals are separated by a scale, 7+10 / 7+10 subdigital lamellae under 4th toe (not including ventral claw sheath).

Coloration consists of three-four irregular black bands on dorsum, plus a few irregular faint brown spots on lower flanks, between limb insertions in paratype; five irregular black dorsal bands, interrupted on the vertebral line, plus a few irregular black spots, between the limb insertions in the adult female shown on Fig. 4 ; four black bands plus a few brown spots between limb insertions of juvenile shown on Fig. 3 . The tails of the male paratype and of the unpreserved juvenile shown on Fig. 3 are original and show seven and ten black bands, respectively. The tail of the unpreserved adult female shown on Fig. 4 shows eight black bands before its regenerated, uniformly dark grey, tip.

Distribution and natural history. The species is currently known only from its type locality, a hill in Sai Yok District, Kanchanaburi Province, western Thailand. The hill is part of a range of scattered hills that are approximately 50 kilometers long and 2.5 kilometers wide at their widest area. This range lies parallel to Kwai River, which flows approximately five kilometers to the east. The geology of the hill consists of limestone and mixed types of sendimentary rocks ( Rhodes et al. 2005). The hill slopes gently at its base (167 m asl) where the land has been cleared for agriculture, however at higher altitudes it becomes steeper and is covered with dry evergreen forest and bamboo forest. Cyrtodactylus saiyok sp. nov. was found between 354–525 m asl where high cliffs surround the top of the hill. Limestone outcrops are found in this area, on which Cyrtodactylus tigroides , another, much larger, endemic species, was present. Cyrtodactylus saiyok sp. nov. was only found on small trees, stumps, and on large Aroid plants, never on cliffs or limestone outcrops. The two species of Cyrtodactylus occupy distinct ecological niches, as has been observed in other species of Cyrtodactylus living in sympatry ( Loos et al. 2012). It is interesting to note here that we failed to find any C. cf. peguensis (see Bauer et al. 2003) in the area; a few locals whom we interviewed also had never seen any, while the species is quite common at the Sai Yok Waterfall area only 7.5 kilometers east of the type locality of Cyrtodactylus saiyok sp. nov., across the Kwai River.

It is highly probable that the new species also occurs in the nearby Sai Yok National Park, which offers similar environmental conditions.

A subadult and a pregnant female were found during our survey, indicating that the species probably breeds year-round, similar to C. sumonthai in eastern Thailand ( Panitvong et al. 2012). As far as we know, the species has not been offered for sale in the pet trade.

Etymology. The specific epithet saiyok refers to the name of the district in which the type locality is situated. It is a noun in apposition, invariable. We suggest the following common names: Took-kai Sai Yok ( Thai), Sai Yok bent-toed gecko (English), Cyrtodactyle de Saï Yok (French), Saiyok Bogenfingergecko ( German), Saiyokkromvingergekko (Dutch). The common name Sai Yok Bent-toed Gecko had been proposed by Ellis and Pauwels (2012) for Cyrtodactylus tigroides , for which we here propose the new common name Tiger Bent-toed Gecko.

Figures

FIGURE 1. Type series of Cyrtodactylus saiyok sp. nov., dorsal view (holotype below). Photo. by O. S. G. Pauwels.

FIGURE 2. Type series of Cyrtodactylus saiyok sp. nov., ventral view (holotype below). Photo. by O. S. G. Pauwels.

FIGURE 3. Unpreserved live juvenile Cyrtodactylus saiyok sp. nov. Photo. by N. Panitvong.

FIGURE 4. Unpreserved live adult female Cyrtodactylus saiyok sp. nov. Photo. by N. Panitvong.

Tables

TABLE 1. Meristic and morphometric (in mm) data for the type series of Cyrtodactylus saiyok sp. nov. Paired meristic characters are given left / right.

	THNHM 25602, Holotype	CUMZ-R-0.2320, Paratype
Sex	Male	Male
SVL	61.0	56.7
ForeaL	8.4	8.1
TibiaL	10.5	10.4
TailL	67.5 (original)	66.7 (original)
TailW	3.3	3.5
AG	29.0	26.5
HeadL	18.2	17.1
HeadW	10.2	9.9
HeadH	6.3	6.9
OrbD	4.3	4.3
OrbEar	5.3	4.9
SnOrb	6.4	6.1
NosOrb	4.8	4.3
Interorb	3.8	3.1
EarL	0.7	0.6
Internar	2.1	1.8
DorTub	19	18
PreclPo	5	5
FemPi/FemPo	0	0
Ven	23	24
SL	9/10	10/9
IL	9/9	9/9
InterorbSc	15	14