Results

Description of specimen. Adult male SVL 85.7 mm; head moderate in length (HL/SVL 0.27), width (HW/HL 0.64), flattened (HD/HL 0.38), distinct from neck, triangular in dorsal profile; lores weakly concave anteriorly, weakly inflated posteriorly; prefrontal region concave; canthus rostralis rounded; snout elongate (SN/HL 0.42), flat, rounded in dorsal profile; eye large (ED/HL 0.23); ear opening elliptical, obliquely oriented, moderate in size; eye to ear distance slightly greater than diameter of eye; rostral rectangular, partially divided dorsally by inverted Y-shaped furrow, bordered posteriorly by large left and right supranasals and one small azygous internasal, bordered laterally by first supralabials; external nares bordered anteriorly by rostral, dorsally by large supranasal, posteriorly by two moderately sized postnasals, bordered ventrally by first supralabial; 11(R,L) rectangular supralabials extending to below midpoint of eye, second–fifth supralabials slightly larger than first; 9 (R,L) infralabials tapering smoothly to slightly past the termination of enlarged supralabials; scales of rostrum and lores flat, slightly larger than granular scales on top of head and occiput; scales of occiput intermixed with small, rounded, tubercles; superciliaries elongate, largest anteriorly; mental triangular, bordered laterally by first infralabials and posteriorly by large left and right trapezoidal postmentals contacting medially for ~50% of their length posterior to mental; one row of slightly enlarged, elongate sublabials extending posteriorly to fifth infralabial; gular and throat scales small, granular, grading posteriorly into slightly larger, flatter, smooth, imbricate, pectoral and ventral scales. Body relatively long (AG/SVL 0.49) with well-defined ventrolateral folds; dorsal scales small, granular, interspersed with small, smooth, rounded, semi-regularly arranged tubercles extending from top of head onto base of tail but no farther; approximately six longitudinal rows of tubercles at midbody; approximately 26,25 (R,L) paravertebral tubercles; 27 flat, imbricate, ventral scales much larger than dorsal scales; 11 enlarged precloacal scales, eleven bearing pits; deep precloacal groove or depression absent; one row of large post-precloacal scales on midline. Forelimbs thin, relatively long (FL/SVL 0.18); lacking tubercles, granular scales of forelimbs slightly larger than those on body; palmar scales rounded, slightly raised; digits well-developed, inflected at basal interphalangeal joints, slightly narrower distal to inflections; subdigital lamellae transversely expanded, those proximal to joint inflections much wider than those distal to inflections; claws well-developed, sheathed by a dorsal and ventral scale; hind limbs thin, wider than forelimbs, long (TBL/SVL=0.20), covered dorsally by granular scales not interspersed with tubercles, larger and flat anteriorly; ventral scales of thighs flat, imbricate, larger than dorsals; subtibial scales large, flat, imbricate; one row of 12,13 (R,L) enlarged femoral scales terminating distally before knee, not continuous with enlarged precloacal scales; proximal femorals about the same size as distal femorals; plantar scales flat; digits well-developed, inflected at basal interphalangeal joints; basal subdigital lamellae greatly expanded transversely, extending well-beyond body of digit, claws well-developed, sheathed by a dorsal and ventral scale at base; and 10,10 (R,L) wide proximal subdigital lamellae on fourth toe, 10,11 (R,L) more narrow lamellae distal to joint inflection, 20,21 (R,L) total subdigital lamellae.

Original tail long (TL/SVL 1.34), thin, 115.1 mm in length, 5.6 mm wide at base, tapering to a point; dorsal caudal scales small, generally square; median row of subcaudals significantly larger than dorsal caudals, transversely expanded, not extending up onto lateral side of tail; body tubercles not extending beyond base of tail; hemipenal swelling visible at base of tail, two large postcloacal tubercles on either side; and postcloacal scales flat, imbricate.

Colouration in life (Fig. 2). Ground color of top of head, limbs, and dorsum light-brown; top of head immaculate; straight-edged, dark-brown nuchal loop extends from posterior margin of one orbit to posterior margin of other orbit; no dark-colored banding on nape; three dark-brown, immaculate, straight-edged, dorsal body bands terminating above the ventrolateral folds extending from shoulders to pelvis, dark-colored body bands narrower than light-colored immaculate interspaces, not edged with light-colored tubercles; one dark-colored sacral band; limbs brown, immaculate; 10 wide, dark-brown caudal bands slightly wider than 11 light-colored caudal bands; all caudal bands immaculate, posterior caudal bands encircle tail; iris gold, bearing thin, black reticulations; venter beige with faint, dark mottling on lateral edges of belly; undersides of limbs and subcaudal region beige with faint yellow mottling at lateral edges.

Natural history. The adult male specimen of Cyrtodactylus disjunctus (USMHC 2935) was collected at Tasik Meranti, Perlis (Fig. 4). It was drizzling at the time of collection (2351 hrs) and the area was wet owing to an earlier downpour that day. The specimen was seen resting on a horizontal branch approximately 2 m above a limestone (karst) outcropping. When approached, the specimen tried to drop from the branch onto the karst. Prior to its discovery, other lizards, suspected to be of the same species were seen nearby. Among them was one gravid female observed crawling on the karst outcrop. These specimens were either unreachable or eluded capture. Other species seen in the area included C. macrotuberculatus Grismer & Ahmad, 2008; Cnemaspis biocellata Grismer, Chan, Nasir & Sumontha, 2008; a gravid Acanthosaura meridiona Trivalairat, Sumontha, Kunya & Chiangkul, 2022; multiple juvenile Calotes emma Gray, 1845; Hylarana nicobariensis Stoliczka, 1870; H. cf. labialis (Boulenger, 1887); Draco formosus Boulenger, 1900; Hylarana malayana (Sheridan & Stuart, 2018) and Grillitschia aceras (Boulenger, 1903).

Discussion

The collection of Cyrtodactylus disjunctus at Tasik Meranti represents the first documented record of this species in Peninsular Malaysia and is a range extension of approximately 13 km to the southeast across the karstic Banjaran Nakawan from the type locality at Meung Satun, Satun Province, Thailand (Fig. 1). It is also represents the first male specimen of the species which enables researchers to gain a valuable insight towards the species’ sexual dimorphism. Generally, this newly collected male specimen is larger in terms of the body measurements compared to the type specimen (Table 1). Given that the usual morphology of lizards often shows that females are larger than males (Scharf & Meiri 2013), this might suggest that the holotype is a subadult female instead of an adult female. Since only a single specimen was collected, a proper statistical analysis is impossible until more specimens are obtained. This region represents the southernmost distribution of many Indochinese lizard species and the northern distribution of a number of Sundaic species (Grismer 2011). More importantly this discovery continues to underscore how much diversity—both described and undescribed—remains unknown, especially in areas as well-surveyed as Perlis State Park (Grismer et al. 2008, 2012, 2014a, b, 2019; Chan et al. 2011; Quah & Anuar 2018; Quah et al. 2023). These continuing new discoveries of rare and undocumented species is not only limited to Perlis, but also occurs in well-studied areas in Peninsular Malaysia such as the discovery of second known specimen of Pseudocalotes drogon Grismer, Quah, Wood, Anuar, Muin, Davis, Murdoch, Grismer, Cota & Cobos, 2016 from Fraser’s Hill (Hong et al. 2024), rediscovery of Sphenomorphus malayanus (Doria, 1888) from Cameron Highlands which was subsequently redescribed as S. senja (Grismer & Quah 2015); rediscovery of Calamaria albiventer (Gray, 1834) collected after six decades on Penang Island (Quah et al. 2018), and rediscovery of Cyrtodactylus sworderi (Smith, 1925) from Endau-Rompin State Park (Grismer et al. 2007). If countries are serious about protecting and conserving their natural heritage, then the agencies responsible for granting research permits—as the Forestry Department of Peninsular Malaysia did for this study—should join researchers in their endeavor to conserve biodiversity.