Cyrtodactylus jarakensis, Grismer, Lee, Onn, Chan Kin, Grismer, Jesse L., Wood, Perry L. & Belabut, Daicus, 2008

Grismer, Lee, Onn, Chan Kin, Grismer, Jesse L., Wood, Perry L. & Belabut, Daicus, 2008, Three new species of Cyrtodactylus (Squamata: Gekkonidae) from Peninsular Malaysia, Zootaxa 1921, pp. 1-23 : 11-13

Cyrtodactylus jarakensis sp. nov.

Figure 5

Holotype. Adult female ( ZRC 2.6753; field number DB07[129]) collected by Daicus Belabut (DB) on 25 November 2007 from Pulau Jarak, Perak, West Malaysia (04° 04.001 N, 100° 27.160 E; 20 m asl.).

Diagnosis. Cyrtodactylus jarakensis is distinguished from all other Sunda Shelf species by having a maximum SVL of 67.0 mm; low, rounded, weakly keeled, body tubercles; tubercles occurring on the occiput, forelimbs, hind limbs, and beyond base of tail; 61 ventral scales; subcaudal scales small, nearly granular; proximal subdigital lamellae transversely expanded; 24 subdigital lamellae on fourth toe; smooth transition between postfemoral and ventral femoral scales; no enlarged femoral or precloacal scales or pore-bearing scales; no precloacal groove or depression; no white reticulum on head; large, isolated, dark spots on head and body; distinct black and white caudal bands. These characters are summarized across all Sunda Shelf species in Table 1 .

Description of holotype. Adult female SVL 67.0 mm; head moderate in length (HL/SVL 0.20), wide (HW/HL 0.66), somewhat flattened (HD/HL 0.68), distinct from neck, triangular in dorsal profile; lores weakly inflated, prefrontal region concave, canthus rostralis smoothly rounded; snout elongate (ES/HL 0.41), rounded in dorsal profile; eye large (ED/HL 0.23); ear opening elliptical, moderate in size (EL/HL 0.10), obliquely oriented; eye to ear distance greater than diameter of eye; rostral as wide as high, slightly concave, partially divided dorsally by a series of four granular scales, bordered posteriorly by left and right supranasals, bordered laterally by first supralabials; external nares bordered anteriorly by rostral, dorsally by a large, anterior supranasal and small, posterior supranasal, posteriorly by four (R) and three (L) large postnasals, ventrally by first supralabial; 12 (R,L) square supralabials scales extending to just beyond dorsal inflection of labial margins tapering abruptly below midpoint of eye; second supralabial largest; nine (R) 10 (L) infralabials tapering smoothly posteriorly to beyond orbit; scales of rostrum and lores raised, slightly larger than granular scales on top of head and occiput; scales of occiput intermixed with slightly enlarged tubercles; dorsal superciliaries elongate, smooth; mental triangular, bordered laterally by first infralabials and posteriorly by left and right rectangular postmentals contacting medially for 50% of their length; one row of slightly enlarged, elongate sublabials extending posteriorly to 5th infralabial; gular scales small, granular, grading posteriorly into slightly larger, flatter, throat scales which grade into larger, flat, smooth, imbricate, pectoral and ventral scales.

Body relatively long (AG/SVL 0.46) with well-defined ventrolateral folds; dorsal scales small, granular, interspersed with moderately-sized, rounded, semi-regularly arranged, smooth tubercles; tubercles extend from occiput to anterior one-third of tail; tubercles on occiput and nape relatively small, those on body largest; approximately 19 longitudinal rows of tubercles at midbody; 40 paravertebral tubercles on body; 61 flat, imbricate, ventral scales between ventrolateral, body folds, ventral scales much larger than dorsal scales; 11 large, precloacal scales lacking pores arranged in a chevron; 13 small scales across base of precloacal region; no precloacal groove or depression.

Forelimbs moderate in stature, relatively short (FL/SVL 0.12); raised scales of forearm slightly larger than those of body, interspersed with, small, smooth tubercles; palmar scales low, rounded; digits well-developed, inflected at basal, interphalangeal joints; subdigital lamellae transversely expanded proximal to joint inflections, more granular distally; digits slightly more narrow distal to inflections; claws well-developed, sheathed by a dorsal and ventral scale; hind limbs more robust than forelimbs, moderately short (TBL/SVL 0.12), covered dorsally by granular scales interspersed with larger, smooth tubercles and anteriorly by flat, slightly larger scales; ventral scales of thigh flat, imbricate, slightly larger than dorsals; ventral tibial scales flat, imbricate; no enlarged, femoral scales; postfemoral scales grade imperceptively into ventral, femoral scales; plantar scales low, slightly rounded; digits well-developed, inflected at basal, interphalangeal joints; subdigital lamellae transversely expanded proximal to joint inflections, more granular distally; digits more narrow distal to inflections; 24 subdigital lamellae on 4th toe (R,L); claws well-developed, sheathed by a dorsal and ventral scale.

Tail long, thin, original, 90.3 mm in length, 5.1 mm in width at base, tapering to a point; dorsal scales of base of tail granular becoming flatter and larger posteriorly; no median row of transversely enlarged subcaudal scales on tail; subcaudal scales slightly larger than dorsal caudal scales; caudal tubercles restricted to base of tail, not in longitudinal rows; remainder of tail lacks tubercles; one enlarged, postcloacal tubercle at base of tail; all postcloacal scales flat, imbricate. Additional meristics: TW 5.1 mm; FL and TBL 10.4 mm; AG 30.9 mm; HL 18.5 mm; HW 12.3 mm; HD 12.6 mm; ED 4.2 mm; EE 5.3 mm; ES 7.6 mm; EN 5.8 mm; IO 4.5 mm; EL 1.8 mm; and IN 1.9 mm.

Coloration in life ( Fig. 5 ). Dorsal ground color of head, neck, trunk, limbs, and anterior one-third of tail straw-yellow; head and body overlain by well-defined, isolated, dark brown blotches edged in yellow; dark, U-shaped blotch contacting posterior margins of eyes, followed by a large, dark brown, parietal blotch flanked laterally by single, larger, square, occipital blotches; large, dark, medial nape blotch followed by eight pairs of dark, paravertebral blotches extending to base of tail; three large, dark, blotches on anterior portion of tail; black and white bands on remainder of tail; brown bands on forelimbs; hind limbs mottled; ventral surfaces of head, body and limbs beige, immaculate; subcaudal region darkly mottled.

Distribution. Cyrtodactylus jarakensis is known only from the small, distant island of Jarak, Perak, approximately 45 km off the west coast of southern Perak ( Fig. 1 ).

Natural history. Pulau Jarak is a small, isolated, deep-water islands on the maritime border between Malaysia and Indonesia in the Straits of Melaka. The island consists of a sharp, rocky ridge approximately 1 km in length reaching just over 50 m in elevation. It is densely forested, steep-sided and its shoreline is composed of granite boulders with no beaches. Cyrtodactylus jarakensis are commonly seen at night on both trees and rocks. Lizards are exceptionally fast and difficult to approach and capture. The holotype is a gravid female.

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

Comparisons. The distinctive color pattern ( Fig. 5 ) of Cyrtodactylus jarakensis notably sets it apart from all other Sunda Shelf species to which it is not even remotely similar in this regard. The main problem inherent in any species description based solely on a single specimen is the inability to assess the range of intrapopulational variation that may potentially overlap that of other species, thus precluding the delimitation of discrete species boundaries. This issue is exacerbated further when the only specimen is a female of a new, putatively, sexually dimorphic species (sexual dimorphism being assumed in C. jarakensis based on its occurrence in all other Cyrtodactylus ) as is the case here. However, many of the characters used in this analysis do not vary intraspecifically in the other Sunda Shelf species and to hypothesize that this would not be the case in C. jarakensis , would be foundationless. Thus, the absence of caudal tubercles in C. jarakensis separates it from C. batucolus , C. brevipalmatus , C. cavernicolus , C. consobrinus , C. elok , C. ingeri , C. malayanus , C. matsuii , C. oldhami , C. pantiensis (see below), C. pubisulcus , C. pulchellus , C. peguensis , C. quadrivirgatus , C. seribuatensis , and C. yoshii which all bear caudal tubercles. Its lack of transversely enlarged, median, subcaudal scales separates it from C. aurensis , C. baluensis , C. consobrinus , C. ingeri , C. malayanus , C. oldhami , C. peguensis , C. pulchellus , and C. thirakhupti which have transversely enlarged subcaudals. The smooth transition between postfemoral and ventral femoral scales in C. jarakensis distinguishes it from C. baluensis , C. batucolus , C. brevipalmatus , C. marmoratus , C. matsuii , C. oldhami , C. pantiensis (see below), C. pulchellus , C. semenanjungensis , C. seribuatensis , C. sworderi , C. thirakhupti , and C. tiomanensis where this transition is abrupt. Due to the uniqueness of this species we are, at this point in time, unable to provide a viable hypothesis as to which species C. jarakensis may be related and will await the completion of a phylogenetic analysis of Cyrtodactylus (Bauer et al. in prep.). Its description will be notably expanded with the acquisition of males, especially regarding the presence or absence of femoral and precloacal pores and their arrangement.

Figures

FIGURE 1. Distribution of Cyrtodactylus jarakensis on Pulau Jarak, Perak; C. batucolus on Pulau Besar, Melaka; and Cyrtodactylus pantiensis at Bunker Trail, Johor and the Sungai Udang Recreational Forest, Melaka.

FIGURE 5. Holotype of Cyrtodactylus jarakensis (ZRC 2.6753) from Pulau Jarak, Perak.