Gekko shiva, Pauwels & Meesook & Donbundit & Jindamad & Topai & Sumontha, 2025

Gekko shiva sp. nov.

( Figures 1–7 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 6 View FIGURE 7 )

Holotype. CUMZ-R 2627 (field no. MS 751), adult male caught on 30 June 2024 in Tham (= Cave) Phra Siwa (13°19’16.0”N, 102°19’40.1”E), Khao (= Mountain) Kok Ma Muang, Khlong Hat District, Sa Kaeo Province, eastern Thailand, by W. Meesook, N. Donbundit, M. Sumontha, T. Jindamad and N. Topai. GoogleMaps

Paratypes (5). CUMZ-R-2628–2629 (field nos. MS 752 and MS 753 respectively, adult females), same locality, collecting date and collector as holotype GoogleMaps ; CUMZ-R-2630 (field no. 754, adult male), MS 755 (adult male) and MS 756 (adult male) caught on 1 st July 2024, 4 October 2024 and 4 October 2024 respectively, at Phet Pho Thong (13°24’50.6”N 102°19’37.9”E), Khao Leuam, Khlong Hat District, Sa Kaeo Province, by the same collectors as the holotype GoogleMaps .

Diagnosis. Gekko shiva sp. nov. can be distinguished from all other congeneric species by the combination of its maximal known SVL of 131.9 mm, lack of contact between nostrils and rostral, 28 or 29 interorbital scales between supraciliaries, 80–86 scale rows around midbody, 18 dorsal tubercle rows at midbody, 35–37 ventral scale rows at midbody, 9–12 precloacal pores in males, one or two postcloacal tubercle on each side of the base of the tail, 13–15 subdigital lamellae on 1st toe and 18 or 19 on 4th toe, no Y-shaped mark on head, white spots on head, brown dorsal background with irregular bands of white spots on dorsum, yellow venter, and greenish golden iris.

Description of holotype. Adult male ( Figures 1 View FIGURE 1 and 2 View FIGURE 2 ). SVL 131.9 mm. Head long (HeadL/SVL ratio 0.28), broad (HeadW/HeadL ratio 0.64), depressed (HeadD/HeadL ratio 0.34), strongly distinct from the neck.

Lores and interorbital region slightly depressed. Snout moderate (SnOrb/HeadL ratio 0.41), less than twice eye diameter (OrbD/SnOrb ratio 0.68); scales on snout and forehead small to moderate in size, granular and slightly domed to flattened; scales on snout larger than those on interorbital region. Eye relatively large (OrbD/HeadL ratio 0.28). Pupil vertical with crenulated margins. Supraciliaries short. Ear opening oval, near-vertically oriented, moderate (EarL/HeadL ratio 0.09); eye to ear distance subequal to diameter of orbit (OrbEar/OrbD ratio 0.95). Rostral nearly twice wider (5.0 mm) than deep (2.8 mm). No rostral groove present; two much enlarged supranasals partly separated posteriorly by a single, small, internasal; rostral in contact with supralabials I and supranasals. Nostrils oval, each surrounded by supranasal, first supralabial, two dorsally located postnasals and a large nasal, which enters the nostril forming a recessed valvular flange in its posterior half. Mental triangular, distinctly wider (4.1 mm) than deep (2.8 mm) and not deeper than infralabials; one pair of greatly enlarged postmentals meeting behind the mental. Each postmental bordered anteriorly by first infralabial, medially by mental, laterally by the first scale in a row of enlarged scales bordering the infralabials, and posteriorly by two chin shields (larger than the granular gular scales), the medial one in shared contact with both left and right postmentals. Infralabials bordered by a row of enlarged scales, decreasing in size posteriorly. Enlarged supralabials to midpoint of orbit 13 (left and right); supralabials to angle of jaws 16 (left)/15 (right); enlarged infralabials 15 (left)/14 (right). Interorbital scale rows across narrowest point of frontal 12, between supraciliaries 29. Supraorbital scales slightly heterogeneous in size, largest at medial edge of orbit in midorbital position.

Body robust, trunk relatively long (TrunkL/SVL ratio 0.46), dorsoventrally depressed in cross-section, with distinct ventrolateral folds without denticulate margins. Dorsal scales heterogeneous, granular, rectangular to oval, and flattened. Regularly arranged, rounded tubercles, about seven to eight times size of dorsal granular scales, extending from posterior margin of orbit to tail; tubercles slightly smaller on parietal region than elsewhere; tubercles in 18 rows at midbody. Ventral scales subimbricate, becoming granular and much smaller in gular region. Midbody scale rows across belly between ventrolateral folds 35. Twelve pore-bearing precloacal scales, in a continuous angular row.

Scales on palm and sole smooth, flat, rounded. Scales on dorsal aspects of hind limbs heterogeneous—granular, intermixed with larger tubercles, some conical, others flattened. Scales on dorsal surface of forelimb proximal to elbow subimbricate, weakly heterogeneous, those distal to elbow granular, intermixed with larger tubercles. Fore- and hind limbs moderately long, stout; forearm and tibia moderately long (FAL/SVL ratio 0.13; TibL/SVL 0.17). Digits relatively short; digit I, both manus and pes, clawless, all remaining digits strongly clawed; distal portions of digits strongly curved, arising from distal portion of expanded subdigital pad. Scansors beneath each toe undivided; scansors from proximalmost at least twice diameter of palmar scales to distalmost: 14-14-17-17-14 (left manus), 14-14-16-19-13 (right manus), 14-14-16-18-17 (left pes), 14-15-17-19-16 (right pes). Relative length of digits of manus: IV>III>V>II>I; and of pes: IV>III>V>II>I.

Tail slightly depressed, about half-regenerated (TailL 101.8 mm, of which 57.7 mm regenerated); dorsal surface of tail covered with small, square to oval, juxtaposed to weakly subimbricate granules forming more or less regular transverse rows. On the original part of the tail, median pair of enlarged subcaudal plates extending more than half of the width of tail. Posterior portion of dorsum of each tail segment with a single transverse row of six enlarged, rounded tubercles (no tubercles on the regenerated part of the tail). A single post-cloacal tubercle on each side of tail base.

Coloration in life. Dorsal surface of head, dorsum, and dorsal surfaces of members and original part of tail uniformly brown, with very contrasting, white spots (generally covering one tubercle and a patch of adjacent small scales) arranged in irregular transverse rows. Background color of dorsal surfaces of fingers and toes brown as dorsum, with some white tubercles. In the anterior, original, half of the tail, a single irregular dorsal transverse row of white spots, just behind hemipenial swellings. Posteriorly, this white row is followed by two regularly disposed, black transversal dorsal bands; these bands are absent from the regenerated part of the tail. No Y-shaped mark on head. Iris greenish golden. Supralabials brown, speckled with yellow, and with a series of contrasting white spots along the lip. Tongue pink. Infralabials brown, speckled with yellow. Throat uniformly bright yellow. Lower flanks and sides of venter brown as dorsum. Mid venter and lower surfaces of limbs and tail yellow. Palms gray. Finger and toe lamellae white. In preservative the background color of the dorsum turns to dark grey, the white spots remaining very contrasting, and the yellow ventral surfaces turn to white ( Figures 6 View FIGURE 6 and 7 View FIGURE 7 ).

Variation. Main morphometric and meristic characters of the type series are provided in Table 1 View TABLE 1 . Morphological characters of the paratypes agree in most respects with the holotype. The females lack precloacal pores. Only two types, the male paratypes CUMZ-R-2630 and MS 755 , have an original tail; their TailL/SVL ratios are 0.93 and 1.10, respectively.

Distribution and natural history. The two localities where the new species was found belong to a North-South alignment of limestone reliefs in Sa Kaeo and Chanthaburi provinces, along the Cambodian border ( Jantarit & Ellis 2023; Figures 8 View FIGURE 8 and 9 View FIGURE 9 ). These reliefs, surrounded by cultivated lands, represent the western foothills of the Cardamom Range. Both localities are at less than five kilometers from the area formerly designated as the Roneam Daun Sam Wildlife Sanctuary. The latter sanctuary, created in 1993, was however rapidly and totally degraded by human activities, until it lost all its forest cover and was degazetted by the Cambodian Government in 2018 ( Graham et al. 2021).

Nothing is known about the diet or the reproduction of the new species. At the type-locality, individuals were observed inside the cave and on limestone rocks near the cave entrance.The species is nocturnal and locally common. Within Phra Siwa Cave or near its entrance ( Figure 9 View FIGURE 9 ), Gekko (Gekko) shiva sp. nov. individuals were observed in direct proximity to Malayemys macrocephala (Gray) ( Geoemydidae ), Calotes versicolor (Daudin) ( Agamidae ), Boiga cyanea (Duméril, Bibron & Duméril) , Chrysopelea ornata (Shaw) , Lycodon capucinus (Boie) and L. davisonii (Blanford) , Ptyas mucosa (Linnaeus) ( Colubridae ), Bungarus candidus (Linnaeus) , Ophiophagus hannah (Cantor) ( Elapidae ), Cnemaspis chanthaburiensis Bauer & Das , Cyrtodactylus khlonghatensis Ampai, Rujirawan, Yodthong, Termprayoon, Stuart &Aowphol , Dixonius cf. siamensis Boulenger , Gehyra mutilata (Wiegmann) , Gekko (Gekko) gecko (Linnaeus) , Hemidactylus frenatus Duméril & Bibron and H. platyurus (Schneider) ( Gekkonidae ), Psammodynastes pulverulentus (Boie) (Psammodynastidae), Malayopython reticulatus (Schneider) ( Pythonidae ), Sphenomorphus maculatus (Blyth) and Subdoluseps bowringii (Günther) ( Scincidae ), Varanus salvator (Laurenti) ( Varanidae ), Calloselasma rhodostoma (Kuhl) , Trimeresurus aff. cardamomensis (Malhotra, Thorpe, Mrinalini & Stuart) ( Viperidae ) and Xenopeltis unicolor Reinwardt ( Xenopeltidae ). At Phet Pho Thong it was also found in syntopy with Cyrtodactylus khlonghatensis .

Etymology. The specific epithet shiva is a name in apposition, invariable, based on the name of the type locality, Tham Phra Siwa, dedicated to Shiva, the god of destruction, a prominent deity in Hinduism. We suggest the following common names: ตุ๊กแกศิวะ (Took-kay Siwa; Thai); Shiva Tokay Gecko (English) , and Gecko tokay de Shiva (French).

Comparison to other species. The subgenus Gekko currently includes ten recognized species: G. albofasciolatus (Günther) ; G. gecko (represented by its nominal subspecies and by G. gecko azhari Mertens ); G. hulk Grismer , del Pinto, Quah, Anuar, Cota, McGuire, Iskandar, Wood & Grismer; G. nutaphandi Bauer, Sumontha & Pauwels ; G. pradapdao Meesook, Sumontha, Donbundit & Pauwels ; G. reevesii (Gray) ; G. siamensis Grossmann & Ulber ; G. smithii Gray ; G. stoliczkai Chandramouli, Gokulakrishnan, Sivaperuman & Grismer ; and G. verreauxi Tytler. The main diagnostic characters of these species are compared in Table 2 View TABLE 2 .

Gekko shiva sp. nov. differs from the Bornean G. albofasciolatus by its smaller SVL (131.9 versus 165.1 mm), its much higher DTR number (18 versus 10), its distinctly higher VentR (35–37 versus 26), distinctly lower PrePo number (9–12 versus 16), its greenish golden (versus green) iris, and the absence (versus presence) of a Y-shaped mark on the head.

It can be differentiated from the Bangladeshi Gekko gecko azhari by its smaller SVL (131.9 versus 155 mm), its higher InterCilS number (28 or 29 versus 20–23), lower MSR (80–86 versus 90–97), higher DTR number (18 versus 15), lower SubDLT1 (13–15 versus 17 or 18), lower SubDLT4 (18 or 19 versus 22–24), and the absence (versus presence) of a Y-shaped mark on the head.

It differs from the widespread Gekko gecko gecko by its smaller SVL (131.9 versus 161.0 mm), distinctly higher DTR number (18 versus 11–13), higher VentR (35–37 versus 30–34), different iris color (greenish golden versus pale golden, copper, or brown to olive), and absence (versus usual presence) of a Y-shaped mark on head.

From Gekko hulk , found in the Thai-Malay Peninsula, it can be separated based on its smaller SVL (131.9 versus 161.3 mm), its distinctly higher DTR number (18 versus 9–11), much higher VentR (35–37 versus 22–28), greenish golden (versus turquoise/green) iris, and absence (versus presence) of a Y-shaped mark on head (compare Figures 1–5 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 with photographs of G. hulk in Grismer et al. 2022).

It can be separated from the western Thai Gekko nutaphandi by its higher IL number (11–16 versus 10), higher InterCilS number (28 or 29 versus 24), much lower MSR (80–86 versus 115 or 116), its higher DTR number (18 versus 14), higher VentR (35–37 versus 30 or 31), distinctly lower PrePo number (9–12 versus 17–22), higher SubDLT1 (13–15 versus 12), higher SubDLT4 (18 or 19 versus 15), presence (versus absence) of white spots on the supralabials, and greenish golden (versus brick red) iris (see photographs of G. nutaphandi in Bauer et al. 2008).

Gekko shiva sp. nov. can be readily distinguished from G. pradapdao from central Thailand by its lower MSR (80–86 versus 89–91), higher VentR (35–37 versus 30–34), greenish golden (versus dark brown) iris, much lighter dorsal background color (brown versus dark chocolate brown to black), and bright yellow (versus white) venter.

The new species can be differentiated from the Sino-Vietnamese Gekko reevesii by its much smaller SVL (131.9 versus 173.0 mm), higher VentR (35–37 versus 28–32), lower PrePo number (9–12 versus 13–20), its greenish golden (versus pale golden) iris (see photographs in Rösler et al. 2011), and absence (versus presence) of a Y-shaped mark on the head.

From the central Thai Gekko siamensis (and its junior subjective synonym G. taylori Ota & Nabhitabhata described from Phetchabun, further North, see Figure 8 View FIGURE 8 ), it can be distinguished by its smaller SVL (131.9 versus 150.0 mm), much lower MSR (80–86 versus 121–132), a much less regular dorsal pattern, and a greenish golden (versus green) iris (see photographs in Grossmann & Ulber 1990). A remarkable difference between these two relatively similar species is the presence of white contrasting spots on the dorsal surface of the head and on the supralabials of Gekko shiva sp. nov., absent in G. siamensis (compare Figures 1–5 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 with photographs of G. siamensis in Grossmann & Ulber 1990 and Figures 10 View FIGURE 10 and 11 View FIGURE 11 ).

Gekko shiva sp. nov. can be differentiated from Gekko smithii by its much smaller SVL (131.9 versus 191.0 mm), lower InterCilS number (28 or 29 versus 31–43), lower MSR (80–86 versus 89–141), higher DTR number (18 versus 8–13), lower SubDLT1 (13–15 versus 16–20), greenish golden (versus green) iris, absence (versus presence) of a Y-shaped mark on head (see photographs of G. smithii in Grossmann & Ulber 1990 and Grismer et al. 2022), and by its brown (versus yellow-green to dark green) dorsum background color.

From Gekko stoliczkai , endemic to Nicobar Islands, it is separated by its distinctly higher DTR number (18 versus 10–12), much higher VentR (35–37 versus 21–25), lower PrePo number (9–12 versus 13–15), lower number of postcloacal tubercles (one or two versus three or four on each side), and greenish golden versus bluish iris.

It can be separated from Gekko verreauxi , endemic to the Andaman Islands, by its smaller SVL (131.9 versus 155.0 mm), the lack of contact between its nostril and rostral (versus contact), much higher DTR number (18 versus 11), smaller SubDLT1 (13–15 versus 16–18), and smaller SubDLT4 (18 or 19 versus 20–22).