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Gehyra wongchan sp. nov. (Figures 1–6) Gehyra cf. angusticaudata –– Meesook et al. 2021: 322. Holotype. CUMZ-R-2598 (field no. MS 740), adult male caught on 20 October 2020 in Tham (= Cave) Khao Chan (14°58’35.2”N, 101°18’11.2”E), Tha Luang District, Lopburi Province, central Thailand, by W. Meesook, N. Donbundit and M. Sumontha. Paratypes (4). CUMZ-R-2599 and CUMZ-R-2613 (field nos. MS 261 and MS 262, respectively), adult male and juvenile female collected on 26 April 2008 at Wat Khao Wong (ca. 14°57’51.5”N 100°41’58.3”E), Kok Samrong District, Lopburi Province, by K. Kunya and M. Sumontha. CUMZ-R-2611 and CUMZ-R-2612 (field nos. MS 738 and MS 739, respectively), juvenile male and adult female collected on 26 March 2021; same locality and collectors as holotype. Diagnosis. Gehyra wongchan sp. nov. can be distinguished from all other congeneric species by the combination of its maximal known SVL of 52.4 mm, 8–10 supralabials, 76–80 dorsal and 48–50 ventral scale rows around midbody, absence of skin folds on limbs, 17 or 18 preanofemoral pores in males in a continuous series extending to mid-length of femur (pores absent in females), tail not- to moderately widened behind vent in adults, a single row of widened subcaudals (about 1/3 of the width of tail in its anterior part, progressively occupying the whole width of the tail towards the tip), digits and toes unwebbed, 7 or 8 divided subdigital lamellae on 4th toe, and a dorsal pattern with white spots as large or larger than adjacent crescent-shaped black markings on a beige to light brown background. Description of holotype. Adult male (Figures 1–3 and Table 1). SVL 45.2 mm. Head long (HeadL/SVL 0.32), relatively broad (HeadW/HeadL ratio 0.63), somewhat depressed (HeadD/HeadL ratio 0.34), poorly distinct from neck. Lores and interorbital region slightly inflated; prefrontal region concave; canthus rostralis smoothly rounded. Snout moderate (SnOrb/HeadL ratio 0.33), less than 1.5 times eye diameter (OrbD/SnOrb ratio 0.75); scales on rostrum, lores, top of head and occiput small, granular, lacking enlarged tubercles; scales on snout much larger than those on interorbital region. Eye relatively large (OrbD/HeadL ratio 0.25). Pupil vertical with crenelated margins. Supraciliaries short. Ear opening oval, moderate (EarL/HeadL ratio 0.08); eye to ear distance slightly shorter than diameter of orbit (OrbEar/OrbD ratio 0.89). Rostral more than two times wider (2.7 mm) than deep (1.2 mm). No rostral groove present; two much enlarged supranasals separated by two small, antero-posteriorly aligned, granular scales. Rostral in contact with supralabial I, nostrils, supranasals and a granular scale separating the supranasals. Nostrils oval, each surrounded by rostral, supranasal, two postnasals and first supralabial. Interorbital scale rows across narrowest point of frontal 13. Mental triangular, wider (2.6 mm) than deep (1.8 mm), much deeper than infralabials; mental in contact with four scales: laterally with first infralabials and posteriorly with a pair of greatly enlarged and elongate inner postmentals meeting behind the mental. Each postmental bordered anteriorly by first infralabial, medially by mental, laterally by an enlarged chin shield (outer postmental), and posteriorly by undifferentiated granular gular scales. Including the two postmentals, there are two pairs of enlarged chin shields. Enlarged supralabials to midpoint of orbit 8 (left and right); supralabials to angle of jaws 10 (left and right); enlarged infralabials 10 (left and right). Gular scales small, subimbricate, grading posteriorly into slightly larger, subimbricate pectoral scales, which grade posteriorly into larger, subimbricate ventrals. Body robust, trunk relatively long (TrunkL/SVL ratio 0.63), dorsoventrally depressed in cross-section, with poorly distinct ventrolateral folds. Dorsal scales small, granular to subimbricate, without tubercles. Ventral scales slightly larger than dorsals. Midbody scale rows across belly to ventrolateral folds 48. No enlarged, precloacal scales. Seventeen pore-bearing precloacal scales, in a continuous row, extending to mid-length of the femur. Scales on palm and sole smooth, flat, rounded. Scales on dorsal aspects of hind limbs homogeneous, granular. Scales on dorsal surface of forelimb homogeneous, granular, flat to slightly conical. Fore- and hind limbs moderately long, stout; forearm and tibia moderately long (FAL/SVL ratio 0.13; TibL/SVL 0.17). No skin folds (sensu Oliver et al. 2016) on fore and hindlimbs. Digits relatively short; digit I, both manus and pes, clawless; all remaining digits strongly clawed; distal portions of digits II-V strongly curved, arising from distal portion of expanded subdigital pad. Scansors beneath each toe divided; scansors 5-6-6-7-7 (left manus), 6-7-7-6-6 (right manus), 6-7-7-8-8 (left pes), 6-7-8-8-7 (right pes). Relative length of digits of manus: IV>V=III>II>I. No webbing between digits or toes. Tail original, depressed, slightly longer than head and body (TailL/SVL ratio 1.10); dorsal surface of tail covered with small, squarish, juxtaposed granules forming more or less regular transverse rows. Median row of strongly enlarged subcaudal plates extending about 1/3 across the width of tail in its anterior part, progressively occupying the whole width of the tail towards the tip (Figure 2). A single, moderate, post-cloacal tubercle on each side of tail base. Coloration in life. Background color of dorsal surface of head, dorsum, and dorsal surfaces of members and tail beige (Figure 1). Poorly contrasted and incomplete preorbital darkish stripe. Supraorbital region bluish. A few irregular black and white spots on the dorsal surface of head. Discontinuous black nuchal collar from one orbit to the other, posteriorly bordered on nape by four white spots. A pair of large white paravertebral spots on neck each anteriorly bordered by a black crescent, each white spot of a diameter of about seven dorsal granular scales. Five similar pairs of large white paravertebral spots between limb insertions, not symmetrically arranged. A few white small spots on lower flanks. A black crescent above sacrum. Dorsal surface of tail showing eight blackish bands, each bordered posteriorly by a whitish thinner band. No bands or spots on the dorsal surfaces of limbs, hands and feet. Throat and belly beige without spots, darkening towards posterior abdomen; pore-bearing scales lighter. Lower surface of limbs, hands, feet and tail brown. In preservative the general color darkens, and the dorsal pattern becomes less contrasting (Figures 2 and 3). Variation. Main morphometric and meristic characters of the type series are provided in Table 1. Morphological characters and color pattern of the paratypes agree in most respects with the holotype. The females lack preanofemoral pores. As with the holotype, all paratypes have an original tail. Females show slightly shorter original tails than males (TailL/SVL ratio 0.87–0.96 vs. 1.09–1.10). The white spots on dorsum are proportionally smaller in juveniles than in adults (Figures 1, 2, 4 and 6). Distribution and natural history. Wat Khao Wong is located about 65 km W of Tham Khao Chan (Figure 14). Both sites lie on limestone hills surrounded by cultivated areas. These hills belong to the “ Saraburi Group Limestones” in the south-west margin of the Khorat Plateau (Ponta et al. 2013; Warren et al. 2014). Nothing is known about the diet or the reproduction of the new species. The holotype was found while it was foraging on a tree near the entrance of Khao Chan Cave (Figures 1 and 15). At the type-locality, individuals were observed inside the cave, on limestone and trees near the cave entrance, and on nearby buildings. The species is locally common. Within Khao Chan Cave Gehyra wongchan sp. nov. individuals were observed in syntopy with Dixonius siamensis Boulenger, Gekko pradapdao and the ubiquitous G. gecko (Linnaeus), Hemidactylus frenatus Duméril & Bibron and H. platyurus (Schneider) (Gekkonidae). We found several individuals of Lycodon capucinus (Boie) in and around the cave, and numerous shed skins of L. davisonii (Blanford) (Colubridae) within the cave. Etymology. The specific epithet wongchan is a name in apposition, invariable, based on the contraction of the localities of the paratypes (Wat Khao Wong) and of the holotype (Tham Khao Chan). In Thai wongchan also means the Moon, in reference to the typical crescent-shaped marks on the nape and dorsum of the new species. We suggest the following common names: จิ้งจกหินวงจันทร์ (Djing-djok-hin wongchan; Thai); Lunulate four-clawed gecko (English), and Gehyra lunulée (French). Comparison to other species. Based on its scalation and dorsal pattern, Gehyra wongchan sp. nov. is readily distinguished from the four other Gehyra species found in mainland Southeast Asia; their main diagnostic characters are compared in Table 2. Gehyra wongchan sp. nov. differs from the Thai endemic G. angusticaudata by its much higher VentR (48–50 vs. 35), much lower PrePo number (17 or 18 extending to mid-length of the femur vs. 31–37 extending the whole length of the femur), absence of webbing on fingers and toes (vs. basal webbing), and its dorsal pattern (large white spots adjacent to black crescents vs. small and nearly indistinct white spots among small black spots, see Figures 7 and 8). The holotype of Gehyra fehlmanni (Figure 9) was collected at ‘‘ 4 km. NW [of] Kanchanaburi, Kanchanaburi Province’’, western Thailand. In the original description, Taylor (1962: 223) noted that the scales on dorsal and lateral surfaces of the holotype were irregular, ‘‘suggesting the possibility that the entire tail has been regenerated’’, but also that the subcaudal scales are widened, ‘‘appearing to be normal and not reproduced’’. The latter fact, combined with the presence on the dorsal surface of the tail of a color pattern pursuing the one seen on the dorsum, and of a lateral fringe of small denticulate scales, seems to indicate that the tail is original. Figure 10 is the first published image of the single paratype of Gehyra fehlmanni, collected at ‘‘Tonka Harbour Tin Mine, Ronpibon, Nakhon Si Thammarat Province’’, southern peninsular Thailand, i.e., at approximately 500 airline km south of the type-locality. Its tail has been lost and was not available to Edward Taylor for the species’ description. Gehyra wongchan sp. nov. can be distinguished from G. fehlmanni by its higher VentR (48–50 vs. 42), lower PrePo number (17 or 18 vs. 22), absence of webbing on fingers and toes (vs. basal webbing), and by its dorsal pattern (transversally elongate black spots with smaller white spots in G. fehlmanni, see Figures 9–11). If the tail of the holotype of Gehyra fehlmanni is indeed original, it is shorter than the tails of males of G. wongchan sp. nov. (TailL/ SVL ratio 0.89 vs. 1.09–1.10). A population of Gehyra cf. fehlmanni has been reported by Grismer et al. (2007) from eastern Cardamom Mountains in Cambodia, exhibiting a dorsal color pattern similar to that of G. fehlmanni but differing in several scalation characters. This Cambodian population differs from Gehyra wongchan sp. nov. by its dorsal pattern (in particular by its transversally elongate black spots, much larger than its white spots) and its 37 PrePo (vs. 17 or 18). Gehyra wongchan sp. nov. can be differentiated from G. lacerata by its lower SL number (8–10 vs. 12), lower PrePo number (17 or 18 vs. 20), its transversely enlarged subcaudals (vs. not enlarged), a tail not- to moderately widened posterior to vent (vs. strongly widened), and by its dorsal pattern (large white spots adjacent to black crescents vs. large white spots, as large or larger than non-adjacent rounded black spots in G. lacerata). Adult Gehyra lacerata individuals have a much more robust habitus than adults of G. wongchan sp. nov. and of the other Thai representatives of the genus (Figure 12). From Gehyra mutilata (and its Malayan subjective synonyms Gehyra butleri Boulenger, 1900, described from Kuala Lumpur, and Peropus packardii Cope, 1869, described from Penang; see synonymies by Taylor 1963 and Grismer 2011), Gehyra wongchan sp. nov. can be distinguished based on its smaller SVL (52.4 vs. 61 mm), higher VentR (48–50 vs. 35–44), lower PrePo number (17 or 18 vs. 24–44), absence of webbing on fingers and toes (vs. basal webbing), its dorsal pattern (large white spots adjacent to black crescents vs. white spots often poorly to not visible in G. mutilata, when present small or not larger than black spots), and a tail not- to moderately widened behind vent (vs. moderately to strongly widened) (Figure 13). |
