Cyrtodactylus batucolus , 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: 3-11
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Cyrtodactylus batucolus sp. nov.
Holotype. Adult male ( ZRC 2.6743) collected by Jesse L. Grismer, Chan K. Onn, Perry L. Wood, Jr., and L. Lee Grismer on 5 June 2008 from Panti Putera (02° 06.581 N, 102 ° 19.757 E; 39 m asl.), Pulau Besar, Melaka, Peninsular Malaysia.
Paratypes. All paratypes ( ZRC 2.6744-49) were collected at the same locality and on the same date as the holotype between 2030 and 0 200 hrs.
Diagnosis. Cyrtodactylus batucolus is distinguished from all other Sunda Shelf species by having a maximum SVL of 75.2 mm; moderately sized, conical, keeled, body tubercles; tubercles occurring on occiput, forelimbs, hind limbs, and beyond base of tail; 38–42 ventral scales; no transversely enlarged, median, subcaudal scales; proximal subdigital lamellae transversely expanded; 17–19 subdigital lamellae on fourth toe; abrupt transition between postfemoral and ventral femoral scales; enlarged femoral and precloacal scales with a continuous series of 43–46 pore-bearing scales in males; precloacal groove absent, precloacal depression present; no white reticulum on head; dark blotches on body. These characters are summarized across all Sunda Shelf species in Table 1.
Description of holotype. Adult male SVL 73.3 mm; head moderate in length (HL/SVL 0.27), wide (HW/ HL 0.68), somewhat flattened (HD/HL 0.64), distinct from neck, triangular in dorsal profile; lores weakly inflated, prefrontal region concave, canthus rostralis smoothly rounded; snout elongate (ES/HL 0.43) rounded in dorsal profile; eye large (ED/HL 0.21); ear opening elliptical, moderate in size (EL/HL 0.11), vertically oriented; eye to ear distance greater than diameter of eye; rostral wider than high, concave, partially divided dorsally, bordered posteriorly by left and right supranasals and medial postrostral (=internasal), bordered laterally by first supralabials; external nares bordered anteriorly by rostral, dorsally by a large, anterior supranasal and small, posterior supranasal, posteriorly by one postnasal, ventrally by first supralabial; 10 (R) 11 (L) square supralabials extending to just beyond dorsal inflection of labial margins tapering in size abruptly below midpoint of eye, first supralabial largest; eight (R,L) infralabials tapering smoothly posteriorly to beyond orbit; scales of rostrum and lores raised, larger than granular scales on top of head and occiput; scales of occiput intermixed with slightly enlarged tubercles; dorsal superciliaries elongate, keeled; mental triangular, bordered laterally by first infralabials and posteriorly by left and right square postmentals which contact medially for 50 % of their length; one row of slightly enlarged, elongate sublabials extending posteriorly to 6 th 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 short (AG/SVL 0.39) with well-defined ventrolateral folds; dorsal scales small, granular, interspersed with moderately sized, conical, semi-regularly arranged, keeled tubercles; tubercles extend from occiput to anterior one-third of tail; tubercles on occiput and nape relatively small, those on body largest; approximately 18 longitudinal rows of tubercles at midbody; 33 paravertebral tubercles on body; 38 flat, imbricate, ventral scales between ventrolateral body folds, ventral scales much larger than dorsal scales; precloacal scales large, seven scales across base of precloacal region; distinct precloacal depression ( Fig. 2View FIGURE 2).
Forelimbs moderate in stature, relatively short (FL/SVL 0.15); granular scales of forearm slightly larger than those of body, interspersed with large, keeled tubercles; palmar scales rounded; digits well-developed, inflected at basal, interphalangeal joints; subdigital lamellae transversely expanded throughout its length; digits slightly more narrow distal to inflection; claws well-developed, sheathed by a dorsal and ventral scale; hind limbs more robust than forelimbs, moderate in length (TBL/SVL 0.16), covered dorsally by granular scales interspersed with larger, keeled tubercles and covered anteriorly by flat, slightly larger scales; ventral scales of thigh flat, imbricate, larger than dorsals; ventral tibial scales flat, imbricate; two rows of enlarged, flat, imbricate, femoral scales extend from knee to knee through the precloacal region where they are continuous with enlarged, precloacal scales; posterior row of enlarged femoral scales contains 44 contiguous pore-bearing scales extending from knee to knee forming a V bordering the precloacal depression; postfemoral scales immediately posterior to the row of pore-bearing scales nearly one-half their size, forming an abrupt union on posteroventral margin of thigh; plantar scales low, slightly rounded; digits well-developed, inflected at basal, interphalangeal joints; subdigital lamellae transversely expanded throughout length of digit; digits more narrow distal to joints; 18 subdigital lamellae on right 4 th toe, 17 on left; claws well-developed, sheathed by a dorsal and ventral scale.
Tail robust, original, 100.1 mm in length, 7.4 mm in width at base, tapering to a point; dorsal scales at base of tail granular becoming flatter posteriorly; no median row of transversely enlarged, subcaudal scales; subcaudal scales much larger than dorsal caudal scales; one pair of paravertebral and dorsolateral tubercle rows on either side of midline; distance between paravertebral tubercle rows much greater than distance between paravertebral and adjacent dorsolateral rows; caudal tubercles decrease in size posteriorly, extending approximately one-half length of tail; three enlarged, postcloacal tubercles at base of tail on hemipenial swelling; all postcloacal scales flat, imbricate.
Coloration in life ( Fig. 3View FIGURE 3). Dorsal ground color of head, neck, trunk, limbs, and tail brown; dark brown and white blotches on top of head, those on occiput tending to form a line from posterior border of one eye to posterior border of other eye; nine pairs of square, dark brown, paravertebral blotches extend from nape to base of tail; blotches countershaded posteriorly by smaller, cream-colored blotches; smaller, dark brown, countershaded markings on flanks; dark speckling and faint, cream-colored banding on limbs; dark body blotches extend onto tail where light countershading transforms into cream-colored bands not encircling tail. Ventral surfaces of head, body and limbs lightly stippled with gray; subcaudal region darkened with fine mottling; iris green.
Variation. The paratypes closely approximate the holotype in all aspects of coloration suggesting sexual dimorphism is absent ( Fig. 4View FIGURE 4). ZRC 2.6748 is generally lighter in overall coloration and along with ZRC 2.6746, has slightly smaller, dark, dorsal blotches. The juveniles ( ZRC 2.6745, 2.6747) also approximate the holotype in coloration and thus ontogenetic change in color pattern is apparently absent unlike many other species of Cyrtodactylus ( Fig. 3View FIGURE 3). Females lack precloacal and femoral pores. Meristic differences are shown in Table 2.
Distribution. Cyrtodactylus batucolus is known only from Pulau Besar, Melaka which lies approximately 5 km off the coast of southern Melaka along the southwestern coastline of Peninsular Malaysia ( Fig. 1View FIGURE 1). This species is expected to be found on some of the other seven satellite islands of the Water Islands Archipelago that have similar, suitable, rocky habitat.
Natural history. Pulau Besar is the largest and centrally located island in the Water Islands Archipelago, extending approximately 2 km in length but not reaching more than 150 m in elevation. Although the island is composed of granitic bedrock which manifests itself in numerous, large, boulder outcrops, virtually no undisturbed forest remains. The vast majority of the island’s interior is now a golf course and its forested periphery is composed of degraded coastal vegetation. A small, elevated section toward the center of the island supports highly disturbed coastal forest. Nonetheless, the extensive boulder outcroppings provide ample microhabitat for Cyrtodactylus batucolus . All lizards were observed at night between 2030 and 0 200 hrs and the vast majority were found on boulders that had cracks or exfoliations into which they could escape. Occasionally, lizards were found on the sides of large trees, in small rocky areas, at the ocean’s edge, or on the sides of cement buildings. This species is ubiquitous in distribution across the island so long as rocks with cracks and exfoliations are nearby regardless of the condition of the forest. A similar situation was noted for the gekkonid Cnemaspis biocellata in that it also occurs in a variety of disturbed habitats so long as its karst microhabitat is intact (Grismer et al. 2008 a).
Cyrtodactylus batucolus was observed to be highly syntopic with Gecko monarchus. These two species are so similar in coloration, overall body stature and behavior, we often had to look at the toes to determine which species we had in hand (expanded toes in G. monarchus and slender toes in C. batucolus ). This would suggest that the microhabitat environment provided by these rock outcroppings is sufficiently rich in resources to allow these species to co-exist in syntopy. Hemidactylus frenatus was only occasionally seen on the rocks where these two geckos were present.
Etymology. The specific epithet batucolus comes from the Malaysian word batu meaning rock and the Latin suffix colo meaning to inhabit or to dwell in.
Comparisons. As illustrated in Table 1, Cyrtodactylus batucolus is readily differentiated from the vast majority of Sunda Shelf species on the basis of morphology and color pattern. In fact, it differs strikingly from all Sunda Shelf species except C. fumosus from Sumatra and C. pulchellus , C. seibuatensis , and C. thirakhupti of the Malay Peninsula, in having a contiguous series of precloacal and femoral pores set in a row of greatly enlarged femoral and precloacal scales ( Fig. 2View FIGURE 2). It can be separated from C. fumosus by having caudal tubercles as opposed to their absence in C. fumosus ; having fewer subdigital lamellae (17–19 vs 20–22); and by the abrupt contact of the large femoral scales with the much smaller postfemoral scales as opposed to these scales smoothly grading into one another as in C. fumosus . From C. pulchellus , C. batucolus is differentiated by being much smaller (maximun SVL 73.3 mm vs. 115.0 mm); having more ventral scales (38–42 vs. 33–35); lacking transversely enlarged, median, sucaudal scales as opposed to their presence in C. pulchellus ; and having a blotched dorsal pattern as opposed to a banded dorsal pattern as in C. pulchellus . Cyrtodactylus batucolus differs from C. thirakhupti in its smaller maximum SVL (73.3 mm vs. 80.0 mm); having caudal tubercles as opposed to their absence in C. thirakhupti ; its lack of transversely enlarged, median, sucaudal scales as opposed to their presence in C. thirakhupti ; having fewer subdigital lamellae on the fourth toe (17–19 vs. 20– 21); lacking a light colored, reticulate pattern on the top of the head as opposed to its presence in C. thirakhupti ; and having a blotched dorsal pattern as opposed to a banded dorsal pattern as in C. thirakhupti . Cyrtodactylus batucolus is strikingly similar C. seribuatensis ( Table 1; Fig. 3View FIGURE 3), another insular endemic found on small islands off the southeast coast of Peninsular Malaysia. Cyrtodactylus batucolus differs from C. seribuatensis by having seven precloacal scales in the posteriormost row between the opposing, enlarged, femoral scales as opposed to there being 8–10 in C. seribuatensis (i.e. the scales are larger in C. batucolus ; Fig. 2View FIGURE 2); having wide, subdigital scales distal to the joint inflections as opposed to these scales being granular; having the paravertebral rows of caudal tubercles being widely separated from one another across the midline of the tail as opposed to being equidistant from each other and the dorsolateral rows of caudal tubercles as in C. seribuatensis ; the white markings countershading the dark, dorsal blotches tending to not form transverse bands as they do in C. seribuatensis ( Fig. 3View FIGURE 3); and overall body tuberculation being less pronounced and less conical as opposed to the strongly tuberculate condition in C. seribuatensis . These two species are very dissimilar in life history, C. seribuatensis being restricted to the intertidal zone ( Youmans & Grismer 2006) and C. batucolus being ubiquitous.
Remarks. We believe the close phenetic similarity between Cyrtodactylus batucolus and C. seribuatensis and their major, morphological departure form all other Sunda Shelf species of Cyrtodactylus is due to recency of common ancestry via parallel evolution and not convergence. Both species occur at the same latitude on small, rocky, shallow water, landbridge islands on opposite sides of the Malay Peninsula which were isolated from the peninsular at the same time during the last glacial melt 8–12 thousand years ago ( Voris 2000). Either the peninsular ancestor of these species went extinct or it has not yet been discovered (see below).
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