Cyrtodactylus phetchaburiensis, Pauwels, Olivier S. G., Sumontha, Montri & Bauer, Aaron M., 2016

Pauwels, Olivier S. G., Sumontha, Montri & Bauer, Aaron M., 2016, A new Bent-toed Gecko (Squamata: Gekkonidae: Cyrtodactylus) from Phetchaburi Province, Thailand, Zootaxa 4088 (3), pp. 409-419 : 410-415

Cyrtodactylus phetchaburiensis sp. nov.

Figs. 1–3

Holotype. IRSNB 2682 (formerly IRSNB 16682), adult male ( Fig. 1 ); Thailand, Phetchaburi Province, Tha Yang District, Klatluang Subdistrict, Khao (= Mountain) Tomo, Tham (= Cave) Khao Tomo (12º47.98’N, 99º44.36’E), collected by local villagers, September 2003.

Paratype. IRSNB 2683 (formerly IRSNB 16650), adult female ( Fig. 2 ); Thailand, Phetchaburi Province, Tha Yang District, collector unknown, no date.

Additional specimens. Other Phetchaburi material initially referred to C. oldhami is here tentatively assigned to Cyrtodactylus phetchaburiensis sp. nov., but with some reservation (see Discussion): THNHM 1247–1248, Thailand, Phetchaburi Province, Tha Yang District, Kaeng Krachan National Park, along Pala-U Waterfall; THNHM 1256–1257, 1283–1284, Thailand, Phetchaburi Province, Tha Yang District, Kaeng Krachan National Park, Khao Phanoen Thung; THNHM 20245–20249 (formerly TNRC 52-3868–3872) ( Fig. 3 ), Thailand, Phetchaburi Province, Tha Yang District, Kaeng Krachan National Park, near km 23 on the road from Thung Peak (12°47’N, 99°23’E, 900 m elevation), collected by J. Nabhitabhata, 22 June 1990.

Diagnosis. A medium-sized Cyrtodactylus (SVL to at least 63.2 mm); body slender; limbs and digits relatively long, slender; original tail longer than SVL; enlarged pair of first postmental scales in contact with one another behind mental, a smaller pair of enlarged chin shields (second postmentals) lateral to these; small, mostly keeled tubercles in 20 regular longitudinal rows on dorsum; 33 scales across mid-venter between lowest rows of flank tubercles; ventrolateral folds weakly developed and atuberculate; enlarged row of femoral scales present; five precloacal pores in male, femoral pores and precloacal groove absent; 5–6 broad basal lamellae and 11 narrow distal lamellae beneath digit IV of pes; most of post-pygal portion of tail atuberculate, a single median row of transversely enlarged subcaudal scales present. Colour pattern of large, dark markings with diffuse edges on a fawn background extending from shoulders to sacrum. A pair of dark scapular patches and a broad occipital band outlined by thin white borders. Flanks pale brown with scattered lighter blotches. Tail distinctly banded with thicker brown annuli, becoming darker posteriorly, alternating with narrower white annuli or bands.

Description of holotype. Adult male. SVL 57.5 mm; TailL 70.8 mm (original). Head long (HeadL/SVL ratio 0.31), moderately narrow (HeadW/HeadL = 0.60), not markedly depressed (HeadH/HeadL = 0.40), clearly distinct from neck. Loreal region weakly inflated, canthus rostralis not prominent. Snout moderate in length (SnEye/HeadL = 0.38), somewhat acuminate; longer than eye diameter (OrbD/SnEye = 0.65); scales on snout small, oval to oblong, weakly conical with apex directed posteriorly, somewhat heterogeneous, distinctly larger than those on crown, interorbital and occipital regions. Eye moderately large (OrbD/HeadL = 0.25); pupil vertical with crenelated margins; supraciliaries short, minute spines on posterior 60% of scales; anterior supraciliaries largest and bearing a central keel that becomes less pronounced posteriorly. Ear opening obliquely elliptical, demarcated posteroventrally by a small fold of skin, large (EarL/HeadL = 0.11); eye to ear distance slightly greater than diameter of eyes (EyeEar/OrbD = 1.10). Rostral much wider (3.0 mm) than deep (1.9 mm), rostral crease about one half height of rostral. Two enlarged, rhomboidal supranasals separated by a single, small, pentagonal internasal. Rostral in contact with first supralabials, nostrils, internasal and supranasals. Nostrils oval, slightly posterolaterally-directed, each surrounded by supranasal, rostral, first supralabial, two distinct postnasals, and posteroventrally by a crescentic nasal, occluded posteromedially by a narial valve. Two to three rows of small scales separate orbit from supralabials. Mental triangular with acute posteriorly-oriented apex separating anterior 40% of postmentals, wider (2.4 mm) than deep (1.8 mm). A pair of enlarged postmentals in contact behind mental, each bordered anteromedially by mental, anterolaterally by first infralabial, posterolaterally by an enlarged lateral chinshield (= second postmental) approximately 40% size of first postmental, and posteriorly by three slightly enlarged granules. Supralabials to midorbital position 8 (both sides); enlarged supralabials to angle of jaws 12 (right) to 13 (left). Infralabials 11 (both sides). Interorbital scale rows across narrowest point of frontal bone 15; 47 scales between left and right supraciliary rows.

Body slender, elongate (TrunkL/SVL = 0.41) with faintly demarcated ventrolateral folds lacking serrations, tubercles, or spines. Dorsal scales exclusive of tubercles largely homogeneous, conical with slightly posteriorlyoriented apices; regularly distributed tubercles (5–8 times size of adjacent scales), most circular, some partly flattened posteriorly, extending from crown and dorsal postorbital region to tail base, on trunk smallest on flanks, largest in paravertebral position and over sacrum, smaller tubercles on postorbital region, crown, occiput, and nape; tubercles conical and erect anteriorly, becoming slightly recumbent and strongly keeled posterior to shoulders, in 20 rows at midbody, typically separated from one another by 1–3 dorsal granules. Ventral scales much larger than dorsals, smooth, oval subimbricate to imbricate, largest on posterior abdomen and especially in precloacal region where they are approximately 3–4 times the size of those at midbody and assume a subtriangular shape. Midbody scale rows across belly to ventrolateral folds ~33. Gular region with homogeneous, smooth, juxtaposed granular scales.

Three (left) and two (right) precloacal pores separated by a single poreless scale. No femoral pores. No precloacal groove. Anteroventral scales of thigh much larger than posteroventral and posterior, with a distinct single row of enlarged femoral scales. Two slightly enlarged, smooth postcloacal spurs, anterior larger than posterior. Hemipeneal bulges evident. Scales on palm and sole smooth, rounded to oval, flattened to slightly domed. Scalation on dorsal surfaces of hind limbs and distal fore limb similar to body dorsum with enlarged, conical, partly keeled tubercles interspersed among smaller scales, tubercles separated from one another by 1–2 small scales; proximal portion of forearm lacking tubercles. Fore and hindlimbs relatively long, slender (ForeaL/ SVL = 0.15; CrusL/SVL = 0.19). Digits relatively short, slender, inflected at interphalangeal joints, especially antepenultimate joint of longer digits, all bearing robust, slightly recurved claws. Basal subdigital lamellae broad, squarish to rectangular with rounded corners, distalmost generally largest, without scansorial surfaces (3-4-4-4-4) both manus, 3-3-3-6-4 left pes, 3-4-4-5-4 right pes); narrow lamellae distal to digital inflection and not including ventral claw sheath: 7-8-10-10-8 (left manus), 7-8-8-9-8 (right manus), 8-9-11-11-11 (left pes), 7-9-11-11-11 (right pes); basalmost usually fragmented; no interdigital webbing. Relative length of digits: IV> III> II ~ V> I (manus); IV ~ V ~ III> II> I (pes).

Original tail, long, subcylindrical, gently tapering to pointed tip; longer than SVL (TailL/SVL = 1.23).

Scales of tail dorsum regular, flat, juxtaposed to weakly imbricate; squarish basally, becoming more rectangular posteriorly; those on basal segments weakly keeled and with slightly pointed free margins, arranged in visible but indistinct segments of 7 scale rows basally. Basalmost postpygal segments with a transverse row 6 enlarged, flattened, keeled tubercles, each 3–4 times size of adjacent scales, decreasing to 4 tubercles in next segment and to 2 in the fifth and sixth postpygal segments, becoming smaller and more weakly keeled posteriorly and lost in the seventh and more posterior segments. Subcaudal scales much enlarged, medial row forming a single series of enlarged plates, two per tail segment.

Measurements (in mm; holotype followed by paratype): SVL 57.5/63.2, ForeaL 8.8/9.2, CrusL 11.1/11.9, TailL 70.8/72.6, TailW 5.4/5.4, TrunkL 23.8/27.8, HeadL 17.8/17.6, HeadW 10.7/11.3, HeadH 7.1/7.5, OrbD 4.4/ 4.2, EyeEar 4.8/4.9, SnEye 6.7/6.9, NarEye 4.6/5.2, Interorb 2.4/2.3, EarL 1.9/1.7, Internar 2.1/2.1.

Coloration in ethanol: Dorsum pale fawn with a series of large, darker, diffusely-edged markings from shoulders to sacrum. A pair of dark scapular patches outlined by a thin white border. Flanks pale brown with scattered lighter blotches.

A well demarcated medium brown band with diffuse white margins extending between postorbital regions of left and right sides across the occiput, band posteriorly bifid across mid-occiput. Crown and snout mid-brown with some lighter and darker irregular patches. Area below occipital band pale cream, posterior supralabials whitish, becoming cream with diffuse darker centres anteriorly.

Limbs pale brown, without distinct markings, feet darker than limbs. Venter beige with all scales bearing tiny brown to black flecks, enlarged precloacal scales paler than remainder of venter. Tail distinctly banded with thicker brown annuli, becoming darker posteriorly, alternating with narrower white annuli; 13 white bands in total, basalmost merely dorsal spots, becoming more entire posteriorly, but not extending onto enlarged median subcaudals, which are brown with a darker free margin.

Variation. The female paratype agrees in nearly all respects of pholidosis with the holotype, but lacks any trace of precloacal pores and has smaller, less prominent postcloacal spurs. The paratype is, however, more boldly patterned. The white stripes on the neck and shoulders fully enclose a dark brown patch that is itself bisected by a white band perpendicular to the long axis of the body. The dark brown blotches on the trunk are discrete and have irregular margins and two parallel rows along the dorsum, with some sequential blotches partly confluent with one another. A more diffuse series of dark blotches is present on each flank. The pale background colour forms an irregular vertebral stripe separating the two paravertebral rows of dark blotches. The crown is distinctly lighter than the occipital band. All labial scales are whitish, without dark centers. The original tail bears 11 white bands, all with dark brown margins; those at midportion of tail enclosing dark brown spots or dashes.

Additional material tentatively referred to Cyrtodactylus phetchaburiensis sp. nov. is similar in scalation features to the holotype, but shows significant variation in dorsal pattern (see Discussion).

Etymology. The specific epithet refers to Phetchaburi Province, south-western Thailand, to which the new species appears to be endemic.

Distribution and natural history. The types are from the Tha Yang District of Phetchaburi Province ( Fig. 4 ). The holotype was found by day at about two meters above the ground within a cave-like crevice formed by large karst boulders in a secondary forest area. Ecological information from other referred specimens, from Kaeng Krachan and Tha Yang districts, suggests that the species occurs in moist evergreen forest and climbs on vegetation-covered walls and tree trunks (Nabhitabhata in Ulber 1993; Pauwels and Chan-ard 2006). Ulber (1993: 195) quoted Jarujin Nabhitabhata’s field notes: ‘‘All specimens collected in moist evergreen forest on the hill, found at night crawling on vertical steep wayside walls of the forest tracks which are covered with dense vegetation and roots in cracks on the walls. Their reddish brown colour blends well with the colour of the lateritic soil. A young was dug out of the rock pile on the forest track’’. It is highly probable that the species will be found on adjacent hills and mountains covered with primary and mature secondary forests in the northern part of Prachuap Khiri Khan Province and in the southern part of Ratchaburi Province.

Comparisons with other species. Wood et al. (2012) established that there was a geographically coherent pattern of phylogenetic relationships among Cyrtodactylus . The Thai material they sampled did not constitute a monophyletic group, but fell out in several clusters in a more inclusive clade that included most members of the genus exclusive of those occurring west of the Salween River. Some groups within this large clade are especially well-circumscribed geographically and are also generally morphologically distinctive from the new species and other Thai Cyrtodactylus . These include the members of the Philippine/Bornean clade, the Australo-Papuan clade and the Lesser Sunda clade (see Wood et al. 2012), as well as the distinctive peninsular Indian/Sri Lankan members of the subgenus Geckoella Gray (Agarwal & Karanth 2015) . However, because Thai, Indochinese, and peninsular Malaysian taxa are less strictly geographically constrained, it is appropriate to compare the new species with all of these.

Ngo & Grismer (2012) and Pauwels & Sumontha (2014) provided a summary of Cyrtodactylus from these regions that have precloacal pores but lack femoral pores, the condition shown by C. phetchaburiensis sp. nov. Among these taxa, the new species may be distinguished by its possession of enlarged femoral scales from C. aurensis Grismer, C. bobrovi Nguyen, Le, Pham, Ngo, Hoang, Pham & Ziegler, C. buchardi David, Teynié & Ohler, C. chauquangensis Hoang, Orlov, Ananjeva, Johns, Hoang & Dau, C. cryptus Heidrich, Rösler, Vu, Böhme & Ziegler, C. durio Grismer, Shahrul, Quah, Muin, Chan, Grismer & Norhayati, C. elok Dring, C. hontreensis Ngo, Grismer & Grismer, C. nigriocularis Nguyen, Orlov & Darevsky, C. otai Nguyen, Le, Pham, Ngo, Hoang, Pham & Ziegler, C. pageli Schneider, Nguyen, Schmitz, Kingsada, Auer & Ziegler, C. pantiensis Grismer, Chan, Grismer, Wood & Belabut, C. pseudoquadrivirgatus Rösler, Vu, Nguyen, Ngo & Ziegler, C. spelaeus Nazarov, Poyarkov, Orlov, Nguyen, Milto, Martynov, Konstantinov & Chulisov, C. stresemanni Rösler & Glaw, C. sumonthai Bauer, Pauwels & Chanhome, and C. sworderi (Smith) .

By its possession of enlarged subcaudal scales, Cyrtodactylus phetchaburiensis sp. nov. is distinguished from C. bidoupimontis Nazarov, Poyarkov, Orlov, Phung, Nguyen, Hoang & Ziegler, C. buchardi, C. bugiamapensis Nazarov, Poyarkov, Orlov, Phung, Nguyen, Hoang & Ziegler, C. cattienensis Geissler, Nazarov, Orlov, Böhme, Phung, Nguyen & Ziegler, C. chauquangensis , C. cryptus , C. cucdongensis Schneider, Phung, Le, Nguyen & Ziegler, C. durio, C. irregularis (Smith) , C. martini Ngo, C. metropolis Grismer, Wood, Onn, Anuar & Muin, C. pantiensis , C. papilionoides Ulber & Grossmann, C. payacola Johnson, Quah, Anuar, Muin, Wood, Grismer, Greer, Chan, Norhayati, Bauer & Grismer, C. pseudoquadrivirgatus , C. quadrivirgatus Taylor, C. stresemanni, C. sworderi , C. vilaphongi Schneider, Nguyen, Duc Le, Nophaseud, Bonkowski & Ziegler , and C. ziegleri Nazarov, Orlov, Nguyen & Ho.

By its possession of 20 longitudinal rows of dorsal tubercles at midbody, Cyrtodactylus phetchaburiensis sp. nov. is distinguishable from C. buchardi (25), C. eisenmanae Ngo (14), C. elok (5–10), C. hontreensis (14), C. nigriocularis (0), C. pageli (9–14), C. papilionoides (12–14), C. spelaeus (10), C. stresemanni (13), C. sumonthai (12), and C. wangkulangkulae Sumontha, Pauwels, Suwannakarn, Nutatheera & Sodob (10).

Among remaining species C. phetchaburiensis sp. nov. is distinguished by a lower number of lamellae beneath digit IV of the pes (16–17) from C. doisuthep Kunya, Panmongkol, Pauwels, Sumontha, Meewasana, Bunkhwamdi & Dangsri (19), C. leegrismeri Chan & Norhayati (18–20), C. puhuensis Nguyen, Yang, Le, Nguyen, Orlov, Hoang, Nguyen, Jin, Rao, Hoang Che, Murphy & Zhang (23), C. samroiyot Pauwels & Sumontha (20), C. sanook Pauwels, Sumontha, Latinne & Grismer (20), C. surin Chan-ard & Makchai (18), C. teyniei David, Nguyen, Schneider & Ziegler (19–20), C. wayakonei Nguyen, Kingsada, Rösler, Auer & Ziegler (19–20); and by a lower number of precloacal pores (5) than C. angularis (Smith) (6), C. doisuthep (6), C. intermedius (Smith) (8–10), C. phuquocensis Ngo, Grismer & Grismer (7–9), C. samroiyot (7), C. teyniei (14 in female holotype) and C. wayakonei (6–8), and a greater number of precloacal pores than C. paradoxus Darevsky & Szczerbak (0–4), and C. thuongae Phung, Van Schingen, Ziegler & Nguyen (0–1).

In addition, the colour pattern of C. phetchaburiensis sp. nov. is distinctly different from all Thai, Malay, and Indochinese Cyrtodactylus that share the lack of femoral pores, presence of six or fewer precloacal pores, enlarged femoral scales present, broad subcaudal scutes, and 19–24 dorsal rows of tubercles (or condition unknown). Specifically, it differs from C. condorensis (Smith) , C. doisuthep , C. leegrismeri , C. puhuensis , C. saiyok Panitvong, Sumontha, Tunprasert & Pauwels, C. samroiyot, C. sanook , C. thochuensis Ngo & Grismer, C. thuongae and C. yangbayensis Ngo & Chan in lacking body bands or well-defined transverse markings, from C. angularis in lacking W-shaped dorsal markings, from C. wayakonei in lacking a reticulated pattern on the head and in possessing a well-defined nuchal loop, from C. paradoxus in lacking a thin, pale vertebral stripe and in having an entire (versus bisected) nuchal loop, from C. peguensis in lacking a reticulated pattern on the head and discrete dark dorsal spots separated by narrow pale margins or reticulations, and from C. oldhami in having a diffuse pattern of dark blotches on a light background rather than four longitudinal series of white spots. In addition, C. phetchaburiensis sp. nov. differs from all of these species is having discrete, dark scapular patches with thin white borders.

Figures

FIGURE 1. Adult male holotype of Cyrtodactylus phetchaburiensis sp. nov. (IRSNB 2682). Scale bar = 10 mm.

FIGURE 2. Adult female paratype of Cyrtodactylus phetchaburiensis sp. nov. (IRSNB 2683). Scale bar = 10 mm.

FIGURE 3. Specimens tentatively referable to Cyrtodactylus phetchaburiensis sp. nov. but showing variation in dorsal colour pattern (see Discussion).

FIGURE 4. Map of the Phetchaburi Province (right) showing the type locality of Cyrtodactylus phetchaburiensis sp. nov. (white circle with black dot). Other specimens referred to the new species have been collected at localities throughout Kaeng Krachan National Park, which occupies most of the western half of the province and abuts the border with Myanmar. Inset map at left shows the relative position of Phetchaburi Province, marked in black.