Cyrtodactylus zebraicus Taylor, 1962

Lee Grismer, Evan S. H. Quah L., Syafiq, Muhamad Fatihah, Rujirawan, Attapol, Aowphol, Anchalee, Ahmad, Amirrudin B. & Anuar, M. S. Shahrul, 2023, Comments on the taxonomic status of Cyrtodactylus zebraicus Taylor, 1962 (Squamata: Gekkonidae) from Northern Peninsular Malaysia, Zootaxa 5318 (4), pp. 489-503 : 492-499

Cyrtodactylus zebraicus Taylor, 1962

( Figs. 3–5 ; Table 2 & 3)

Cyrtodactylus peguensis (in part): Das & Norsham 2007: 77; Grismer 2008: 30

Cyrtodactylys peguensis zebraicus: Ulber 1989: 4 & 5; Denzer & Manthey 1991: 314; Manthey & Grossmann 1997: 226; Das 2010: 213

Referred specimens. USMHC 2635 , collected by Evan S.H. Quah and M.S. Shahrul Anuar on 7 November 2019 at approximately 21:00 h from Perlis State Park , Perlis, Malaysia (approximately 6.698222N, 100.191611E; 144 m elevation) . USMHC 2639 bears the same collection data as USMHC 2635 but was collected on 9 November 2019 . UMTZC 2413 , collected by Muhamad Fatihah Syafiq, Baizul Hafsyam Badli-Sham and Amirrudin B. Ahmad on 5 October 2022 at 20:25 h from Bukit Ayer , Perlis, Malaysia (6.542000N, 100.168000E; 52 m elevation) .

Description of specimen USMHC 2635. Adult male with 62.0 mm SVL; head moderate in length (HL/SVL 0.29), wide (HW/HL 0.58), slightly flattened (HD/HL 0.40), distinct from neck, and triangular in dorsal profile; lores concave anteriorly, inflated posteriorly; frontal region flattened, prefrontal region slightly concave, canthus rostralis rounded; snout short (ES/HL 0.40), rounded in rostral region, eye to snout distance slightly less than head depth; eye large (ED/HL 0.22), eyeball slightly protuberant, eye diameter less than the eye to ear distance, pupil vertical; ear opening elliptical, obliquely oriented, moderate in size (EL/HL 0.09); rostral large, subrectangular, height 1.5 mm, shorter than wide, 2.7 mm, medially divided by a dorsal furrow, reaching to approximately halfway down rostral height, bordered posteriorly by supranasals and internasal, laterally by first supralabials and nostrils; external nares at anterior angle of snout, directed lateroposteriorly, bordered anteriorly by rostral, dorsally by two large supranasals, posteriorly by two smaller postnasals, ventrally by first supralabial; internarial distance narrow; anterior pair of supranasals subrectangular, separated by one small internasal, bordered anteriorly by rostral, laterally by nostrils, posteriorly by posterior supranasal and three smaller scales; one internasal, subhexagonal, vertically arranged, slightly protruding rostral, bordered posteriorly by two small scales; 9/8 (right/left) supralabials extending to below midpoint of eye, 15/12 to below the posterior margin of the eyeball, subrectangular anteriorly, elliptical shape posteriorly; 6/7 infralabials extending to below midpoint of eye, 9/11 to below the posterior margin of the eyeball, larger than supralabials, tapering smoothly posteriorly; scales of frontonasal, prefrontal and lores, small, relatively raised, domed, slightly larger than granular scales on top of head and occiput; scales on occiput intermixed with scattered, slightly larger, more rounded, dome to subconical tubercles, more prominent tubercles between occiput and above ear opening; dorsal supraciliaries crenulated, not elongate or keeled; mental large, triangular, 2.0 mm in width, 1.7 mm in length, bordered laterally by first infralabials and posteriorly by large, right and left trapezoidal postmentals that contact medially for 50% of their length posterior to mental; one row of slightly enlarged chin shields extending posteriorly to sixth (right/left) infralabials; and gular and throat scales small, granular, grading posteriorly into larger, flat, smooth, imbricate, pectoral and ventral scales.

Body relatively short, somewhat stout (AG/SVL 0.46), lacking ventrolateral folds; scales on dorsum small, mostly homogenous, granular, interspersed with larger, irregularly arranged, slightly prominent trihedral keeled tubercles; tubercles extending from occiput beyond to the base of the original portion of tail; tubercles on occiput, nape and anterior of body at level above shoulder smaller, subconical; those mid-dorsally and on the posterior section of the body larger, being more dense, slightly more prominently keeled, and more regularly arranged in sacral region and tail base; tubercles on flanks sparse; approximately 15 longitudinal rows of dorsal tubercles; approximately 22 paravertebral tubercles; 30 flat, imbricate, smooth ventral scales, those near midline larger than those laterally and dorsal scales; femoral are not enlarged; precloacal scales smooth, approximately twice the size of femoral scales; femoral pores absent; seven precloacal scales; six precloacal pores; four rows of enlarged postprecloacal scales; and precloacal groove or depression absent.

Limbs moderately slender;forelimbs relatively short(FL/SVL 0.16); scales on dorsal surface domed to subconical, granular, slightly larger than those on body, interspersed with sparsely enlarged, subconical and trihedrally keeled tubercles; dorsal scales of wrist and palm flat, smooth, round, imbricate; ventral scales of palm flat, weakly rounded, slightly raised, not imbricate, smaller than those on body; 14/14 (right/left) total subdigital lamellae on fourth finger, 4/4 proximal subdigital lamellae rectangular with rounded to weakly rounded corners, broadly expanded proximal to joint inflection on fourth finger, 10/10 distal subdigital lamellae, slightly expanded immediately distal to joint, becoming gradually more expanded near the claw; digits well-developed, relatively long, inflected at basal interphalangeal joints; digits slightly narrower distal to inflections; no interdigital webbing; claw well-developed, relatively short, claw base sheathed by a dorsal and ventral scale; hind limbs more robust than forelimbs, moderate in length (TBL/SVL 0.17); dorsal scales domed to subconical, granular, interspersed with enlarged subconical and trihedrally keeled tubercles, and anterior part of thigh covered by flat, slightly larger, imbricate scales; ventral scales of femora flat, smooth, imbricate, smaller than those on body; small postfemoral scales form an abrupt union with large, flat ventral scales of posteroventral margin of thigh; ventral scales of tibia flat, imbricate; dorsal scales of plantar surface relatively smooth, rounded, imbricate; ventral scales of plantar surface low flat, weakly rounded; 16/16 (right/left) total subdigital lamellae on fourth toe, 5/5 proximal subdigital lamellae, rectangular with rounded to weaky rounded corners, broadly expanded proximal to joint inflection on fourth toe, 11/11 distal subdigital lamellae, slightly expanded immediately distal to joint, becoming gradually more expanded near the claw; digits well-developed, relatively long, inflected at basal, interphalangeal joints; and claw well-developed, relatively short, claw base sheathed by a dorsal and ventral scale.

Tail 41.4 mm in length, regenerated, shorter than SVL (TL/SVL 0.67), moderate in proportions, cylindrical, wide anteriorly, 5.3 mm in width at base, tapering to a tip, covered with small, flat, imbricating scales on the dorsal surface but slightly larger, flat, imbricating scales on ventral surface; dorsal scales of original portion of tail base granular, round, becoming larger, flatter, subimbricate posteriorly on regenerated portions of tail; those on tail base bearing trihedrally keeled tubercles forming paravertebral rows, no caudal furrow; base of tail forming hemipenial swelling; 2/2 (right/left) postcloacal tubercles on the enlarged smooth hemipenial swelling; and postcloacal tubercles approximately equal size.

Coloration in life ( Fig. 2 ). Dorsal ground color of head, body, and limbs light-brown; top of head bearing large, dark-brown blotches edged in yellow, forming a light-colored reticulated pattern; superciliary scales yellow; supralabials and infralabials off-white bearing darker markings; wide, discontinuous, dark-brown nuchal loop edged in yellow, extending from posterior margin of one orbit, across occiput and nape to posterior margin of the other orbit; five dark-brown paravertebral blotches on the dorsum starting from shoulder region on top of the forelimbs until the sacral band, all blotches edged in yellow but the second and third pair of paravertebral blotches not divided medially along the vertebral column; all yellow outlines of the paravertebral blotches extend along the flanks towards the venter to form a series of narrow, yellow bands along the flanks; sacral band between hindlimbs composed of paravertebral blotches; postsacral band composed of confluent blotches; regenerated tail dark-grey with lighter grey and orange-brown speckling; dorsal portion of forelimbs and hindlimbs bearing irregularly shaped yellow banding and reticulations; all ventral surfaces generally greyish white, immaculate, except for ventral surface of knee and elbow region which bear some dark mottling.

Coloration in preservation ( Fig. 2 ). The overall color pattern is similar to that in life except that it is faded. Ground color of head, body, and limbs light-brown; nuchal, body and sacral bands dark brown but slightly lighter than in life; the light-yellow reticulated pattern on the dorsal surfaces of the head, body and limbs faded to off-white; and all ventral surfaces light-beige.

Variation ( Fig. 2 , 3 & 5 ). Morphometric, meristic and color pattern characters of the other referred specimens of C. zebraicus from Peninsular Malaysia are presented in Table 1 . All the specimens are generally similar in most aspects of morphology with subtle variation in color pattern ( Figs. 2 & 3 ). In USMHC 2639 the right 4TLU is damaged and approximately 2/3 of tail is original: bearing four longitudinal rows of dorsal tubercles, two transverse rows of dorsal tubercles extend from tail base to anterior margin of first light caudal band, 4.7 mm from tail base, approximately 8.3% of tail; a single enlarged median row of transverse scales on subcaudal region starting from second light caudal band on original portion of tail and ends at the start of the regenerated portion of the tail. The color pattern of USMHC 2639 is also slightly lighter both in life and preservation and the original portion of the tail bears light and dark caudal bands that completely encircle the tail. Similarly, the tail that is original in UMTZC 2413 bear light and dark caudal bands that completely encircle the tail.

TABLE 1 (Continued)

Distribution in Peninsular Malaysia ( Fig. 1 ). Cyrtodactylus zebraicus is currently only known from around the Nakawan Range in Perlis state but the species may range more widely in Peninsular Malaysia. However, given what is known about its habits in Thailand ( Grismer et al. 2021), it is expected to be confined to only lowland areas in the extreme north at the Malaysian-Thai border, in the states of Kedah, Perak and Kelantan. The extralimital distribution of the species outside of Peninsular Malaysia is in peninsular Thailand, south of the Isthmus of Kra ( Grismer et al. 2021).

Natural history ( Fig. 4 ). In Peninsular Malaysia, C. zebraicus is a habitat generalist and has been found in lowland, semi-deciduous forest ( Sharma et al. 1996, 2001) associated with karstic areas along the Nakawan Range. Specimens USMHC 2635 and 2639 were both observed at night approximately 1m above the ground on the trunks of small trees, in an open area near the forest edge. It was raining the night USM 2635 was found and the gecko was perched on a dry section of the tree trunk and partially protected by low vegetation. In comparison, UMTZC 2413 was found at night crawling in a grassy area bordering the main road that cuts through the forested area. The weather was clear the night UMTZC 2413 was found but it had been raining for a few days beforehand.

Conservation status. At present, there is only limited ecological knowledge for the species in Peninsular Malaysia. Anecdotal observations indicate that Peninsular Malaysian specimens are similar to Thai populations in habits, and it is a habitat generalist that can survive in habitats with moderate human disturbance ( Grismer et al. 2021). In addition, the species occurs in protected areas managed by the Perlis Forestry Department such as Bukit Ayer. As such, we believe that the future of C. zebraicus in the country is secure and we recommend listing it as a species of Least Concern (LC).

Comparison and comments on taxonomy. Cyrtodactylus zebraicus can be easily differentiated from all other species of Cyrtodactylus known in Peninsular Malaysia based on a combination of color pattern and scale characters.

From the agamensis group in Peninsular Malaysia composed of C. jarakensis , C. metropolis , C. pantiensis , C. payacolus , C. semenanjungensis and C. tiomanensis ( Grismer et al. 2021) , C. zebraicus differs by having fewer paravertebral tubercles (22–27 vs. 32–40), fewer ventral scales (30–36 vs. 36–61), fewer subdigital lamellae on fourth toe (13–17 vs. 17–24) and the color pattern on top of head (prominent blotched patterning outlined by white reticulum vs. dark speckling with absence of white reticulum) ( Grismer 2011; Grismer et al. 2014a).

From C. aurensis of the philipinicus group ( Grismer et al. 2021), C. zebraicus differs by its smaller adult size in both sexes (50.0– 65.7 mm SVL vs. 95.0– 99.4 mm SVL), fewer ventral scales (30–36 vs. 45–51), fewer subdigital lamellae on fourth toe (13–17 vs. 18–23), precloacal groove (absent vs. present and deep), color pattern on top of head (prominent blotched patterning outlined by white reticulum vs. lightly colored reticulate pattern) and patterning on body (dense bold banding or blotched pattern on body, and bold light and dark banding on original tail vs. narrow light bands on body and tail) ( Grismer 2011).

From members of the pulchellus group consisting of C. astrum , C. australotitiwangsaensis , C. bintangrendah , C. bintangtinggi , C. dayangbuntingensis , C. evanquahi , C. hidupselamanya , C. jelawangensis , C. langkawiensis , C. lenggongensis , C. macrotuberculatus , C. pulchellus , C. sharkari , C. timur and C. trilatofasciatus ( Grismer et al. 2021) , C. zebraicus can be easily differentiated on the basis of lacking a deep precloacal groove, smaller adult size in both sexes (50.0– 65.7 mm SVL vs. 99.0– 122.2 mm SVL), contiguous series of enlarged pore-bearing femoral and precloacal scales (absent vs. present), color pattern on top of head (prominent blotched patterning outlined by white reticulum vs. generally immaculate with absence of white reticulum) and patterning on body (dense bold banding or blotched pattern on body vs. 3–7 bold, dark bands on the body edged in white) ( Grismer 2011; Quah et al. 2019; Wood et al. 2020).

From members of the brevipalmatus group composed of C. cf. brevipalmatus and C. elok ( Grismer et al. 2021) , C. zebraicus differs by webbing at the base of digits (absent vs. present), caudal fringe of spiny tubercles along tail (absent vs. present), fewer ventral scales (30–36 vs. 36–47), fewer subdigital lamellae on fourth toe (13–17 vs. 19–21), color pattern on top of head (prominent blotched patterning outlined by white reticulum vs. mottled with absence of white reticulum) and patterning on body (dense bold banding or blotched pattern on body vs. color similar to tree bark with usually faint bands and mottling) ( Grismer 2011; Grismer et al. 2022).

From C. durio of the lateralis group ( Grismer et al. 2021), C. zebraicus differs by its smaller adult length in both sexes (50.0– 65.7 mm SVL vs. 79.3 mm SVL in adult male), elongate, spinose tubercles in ventrolateral body fold and on ventrolateral margin of tail (absent vs. present), fewer ventral scales (30–36 vs. 59), fewer subdigital lamellae on fourth toe (13–17 vs. 22), color pattern on top of head (prominent blotched patterning outlined by white reticulum vs. irregular mottling) and patterning on body (dense bold banding or blotched pattern on body vs. squarish blotches on body) ( Grismer 2011).

From C. leegrismeri of the condorensis group ( Grismer et al. 2021), C. zebraicus differs in its smaller adult size in both sexes (50.0– 65.7 mm SVL vs. 90.0–92.0 mm SVL), fewer subdigital lamellae on fourth toe (13–17 vs. 18–21), color pattern on top of head (prominent blotched patterning outlined by white reticulum vs. weak reticulum) and patterning on body (dense bold banding or blotched pattern on body, and bold light and dark banding on original tail vs. dark, indistinct symmetrical blotches on body and tail) ( Grismer 2011).

From members of the sworderi group consisting of C. guakanthanensis , C. gunungsenyumensis , C. quadrivirgatus , C. sworderi and C. tebuensis ( Grismer et al. 2021) , C. zebraicus differs by its smaller adult size in both sexes (50.0– 65.7 mm SVL vs. 71.0– 82.2 mm SVL), fewer paravertebral tubercles (22–27 vs. 32–40) and color pattern on top of head (prominent blotched patterning outlined by white reticulum vs. mottled with absence of white reticulum) ( Grismer 2011; Grismer et al. 2016).

From members of the darmandvillei group composed of C. batucolus and C. seribuatensis ( Grismer et al. 2021) , C. zebraicus differs by its smaller adult size in both sexes (50.0– 65.7 mm SVL vs. 70.1–75.2 mm SVL), fewer ventral scales (30–36 vs. 28–42), fewer subdigital lamellae on fourth toe (13–17 vs. 17–22), contiguous series of enlarged pore-bearing femoral and precloacal scales (absent vs. present), color pattern on top of head (prominent blotched patterning outlined by white reticulum vs. dark speckling with absence of white reticulum) and patterning on body (dense bold banding or blotched pattern on body vs. dark blotches on body, bordered by diffuse, light colored bands or spots) ( Grismer 2011).

From populations of the C. consobrinus complex of the malayanus group ( Grismer et al. 2021), C. zebraicus differs by its smaller adult size in both sexes (50.0– 65.7 mm SVL vs. 117.4–125.0 mm SVL), fewer ventral scales (30–36 vs. 58–65), fewer subdigital lamellae on fourth toe (13–17 vs. 23–28), enlarged pore-bearing femoral scales in males (absent vs. present), and patterning of body (dense bold banding or blotched pattern on body vs. narrow, relatively widely spaced lighter bands) ( Grismer 2011).

Figures

FIGURE 1. Yellow star = type locality of Cyrtodactylus zebraicus at Ron Phibun District, Nakhon Si Thammarat Province, Thailand. Blue circle = Location of the Nakawan Range in Perlis State where C. zebraicus are recorded in Peninsular Malaysia.

FIGURE 2. Peninsular Malaysian specimens of Cyrtodactylus zebraicus: A. Adult male USMHC 2635 from Perlis state. B. Adult female USMHC 2639 from Perlis state. C & D. Dorsal (C) and ventral (D) aspects of the preserved specimens. (Photographs by Evan Quah).

FIGURE 3. A. Adult male Cyrtodactylus zebraicus (UMTZC 2413) from Perlis state, Peninsular Malaysia. B & C. Adult C. zebraicus (AA 07310 and AA 07309) from Ron Phibun District, Nakhon Si Thammarat Province, Thailand. (Photographs by Baizul Hafsyam Badli-Sham [A] & Attapol Rujirawan [B & C]).

FIGURE 4. Habitat of Cyrtodactylus zebraicus in Perlis state, Peninsular Malaysia: A. Perlis State Park. B. Bukit Ayer. (Photographs by Evan Quah [A] & Muhamad Fatihah Syafiq [B]).

FIGURE 5. Variation observed in Cyrtodactylus zebraicus specimens from Thailand: A. Khao Luang Krung Ching. B. Nai Chong. C. Khao Pra Bang Kram. D. Khao Ramrom. E. Khao Pu Khao Ya. F. Khao Phanom Wang. G. Khao Banthad. H. Khao Luang Krung Ching. (All photographs courtesy of Ian Dugdale).