Gekko pradapdao Meesook & Sumontha & Donbundit & Pauwels 2021, sp. nov.
Creators: name: Meesook, Worawitoo
name: Sumontha, Montri
name: Donbundit, Nattasuda
name: Pauwels, Olivier S. G.
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Reptilia
Squamata
Gekkonidae
Gekko
Gekko pradapdao

description: Gekko pradapdao sp. nov.
(Figures 1–6)
Holotype. CUMZ-R 2590 (field nr. MS 733), 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, by W. Meesook, M. Sumontha and N. Donbundit.
Paratypes (3). AUP-02009 and PSUZC-R 738 (field nr. MS 735 and MS 736, respectively), adult males, and CUMZ-R 2591 (field nr. MS 734), adult female. Same locality, collecting date and collector as holotype.
Diagnosis. Gekko pradapdao sp. nov. can be distinguished from all other congeneric species by the combination of its maximal known SVL of 127.1 mm, lack of contact between nostrils and rostral, 24–28 interorbital scales between supraciliaries, 89–91 scale rows around midbody, 16–18 dorsal tubercle rows at midbody, 30–34 ventral scale rows at midbody, 11–13 precloacal pores in males, a single postcloacal tubercle on each side of the base of the tail, 13–16 subdigital lamellae on 1st toe and 17–19 on 4th toe, no Y-shaped mark on head, non-banded dorsal pattern on a dark chocolate brown to black background, and a dark brown iris.
Description of holotype. Adult male (Figures 1–3). SVL 118.0 mm. Head long (HeadL/SVL 0.28), relatively broad (HeadW/HeadL 0.74), somewhat depressed (HeadD/HeadL 0.40), strongly distinct from the neck.
Lores and interorbital region slightly inflated. Snout moderate (SnOrb/HeadL ratio 0.43), less than twice eye diameter (OrbD/SnOrb ratio 0.66); scales on snout and forehead small to moderate in size, granular and slightly domed to flattened; scales on snout much larger than those on interorbital region. Eye relatively large (OrbD/HeadL ratio 0.28). Pupil vertical with crenulated margins. Supraciliaries short. Ear opening oval, vertically oriented, moderate (EarL/HeadL ratio 0.08); eye to ear distance slightly shorter than diameter of orbit (OrbEar/OrbD ratio 0.91). Rostral approximately twice wider (5.6 mm) than deep (2.7 mm). No rostral groove present; two much enlarged supranasals partly separated by a single, small, internasal; rostral in contact with supralabial 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 third. Mental triangular, deeper (3.7 mm) than wide (2.4 mm) and not much 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 10 (left and right); supralabials to angle of jaws 13 (left)-12 (right); enlarged infralabials 11 (left and right). Interorbital scale rows across narrowest point of frontal 12, between supraciliaries 28. Supraorbital scales heterogeneous in size, largest at medial edge of orbit in midorbital position.
Body robust, trunk relatively long (TrunkL/SVL ratio 0.42), dorsoventrally depressed in cross-section, with distinct ventrolateral folds without denticulate margins. Dorsal scales heterogeneous, granular, rectangular to oval, and flattened. Regularly arranged, small (about 6 times size of granules), conical, posteriorly directed tubercles extending from posterior margin of orbit to tail; tubercles smaller on parietal region than elsewhere; tubercles in 18 rows at midbody. Ventral scales smaller than dorsal tubercles, subimbricate, becoming granular and much smaller in gular region. Midbody scale rows across belly between ventrolateral folds 30. Eleven pore-bearing precloacal scales, in a continuous 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 0.15; 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: 13-14-16-15-14 (left manus), 12-13-16-16-13 (right manus), 14-15-17-17-15 (left pes), 13-14-16-17-15 (right pes). Relative length of digits of manus: III>IV=II>I>V; of pes: IV>V>III>II>I.
Tail depressed, slightly longer than head and body (TailL/SVL ratio 1.10); dorsal surface of tail covered with small, square to oval, juxtaposed to weakly subimbricate granules forming regular transverse rows. Median pair of enlarged subcaudal plates extending about 2/3 across the width of tail. Posterior portion of dorsum of each tail segment with a single transverse row of 6 enlarged, rounded tubercles. 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 tail uniformly dark chocolate brown, with very contrasting, white spots (covering one tubercle and sometimes also some adjacent small scales) not arranged in transverse rows. Background color of dorsal surfaces of fingers and toes brown but slightly lighter than dorsum background color, with some white tubercles. In the anterior half of the tail, white dorsal tubercles are more or less arranged in five regularly spaced transverse rows, followed in the second half of the tail by five transverse white bands, the last one near the tail tip. No nuchal collar. No Y-shaped mark on head. Iris dark brown. Infralabials chocolate brown. Throat whitish, with irregularly distributed yellowish scales. Venter and lower surfaces of members and tail whitish, with a few irregular chocolate brown spots, and a few yellowish scales. Palms gray. Finger and toe lamellae white.
Variation. Main morphometric and meristic characters of the type series are provided in Table 1. Morphological characters of the paratypes agree in most respects with the holotype. The female lacks precloacal pores. All three paratypes have a partly regenerated tail; AUP-02009 even shows a bifurcated regenerated tail (Figure 4).
Distribution and natural history. All types and observed individuals were found within Khao Chan Cave, and the species is known only from its type-locality (Figure 7). The cave, in which the species is abundant, has been radically transformed into a Buddhist temple (Figure 8), and is totally surrounded by cultivated fields. The ground of the cave has been tiled; many cracks and holes have been filled with cement. The holotype was found while it was foraging on a plastic barrel (Figure 1). Nothing is known about the diet or the reproduction of the new species. Five other gecko species were found to share the cave with the new species: Dixonius siamensis Boulenger, Gehyra cf. angusticaudata (Taylor), Gekko gecko (Linnaeus), Hemidactylus frenatus Duméril & Bibron and H. platyurus (Schneider). We also found at least 20 shed skins of Lycodon davisonii (Blanford) (Colubridae) within the cave.
Etymology. The specific epithet is a name in apposition, invariable, based on the combination of the Thai words “pradap” (decorated) and “dao” (star). The starry effect is due to the fact that, unlike in other members of the Gecko subgenus such as G. (G.) siamensis or G. (G.) smithii, the white dorsal tubercles are not aligned in transverse rows, but irregularly distributed. It is reinforced by the contrast between the white tubercles and the unusually dark background color of the new species. We suggest the following common names: ตุ๊กแกประดับดาว (Took-kay pradap dao; Thai); Starry Tokay Gecko (English), and Gecko tokay étoilé (French).
Comparison to other species. The subgenus Gekko currently includes seven species: G. (G.) albofasciolatus (Günther); G. (G.) gecko (represented by its nominal subspecies and by G. (G.) gecko azhari Mertens); G. (G.) nutaphandi Bauer, Sumontha & Pauwels; G. (G.) reevesii (Gray); G. (G.) siamensis Grossmann & Ulber; G. (G.) smithii Gray; and G. (G.) verreauxi Tytler. The main diagnostic characters of these species are compared in Table 2.
Gekko (G.) pradapdao sp. nov. differs from the Bornean G. (G.) albofasciolatus by its smaller SVL (127.1 vs. 165.1 mm), its much higher DTR number (16–18 vs. 10), its higher VentR (30–34 vs. 26), lower PrePo number (11–13 vs. 16), its dark brown (vs. green) iris and the absence (vs. presence) of a Y-shaped mark on the head. It can be differentiated from the Bangladeshi Gekko (G.) gecko azhari by its smaller SVL (127.1 vs. 155 mm), its higher InterCilS number (24–28 vs. 20–23), higher DTR number (16–18 vs. 15), lower number of postcloacal tubercles (one vs. 2 or 3), lower SubDLT1 (13–16 vs. 17 or 18), lower SubDLT4 (17–19 vs. 22–24), and the absence (vs. presence) of a Y-shaped mark on the head. It differs from the widespread Gekko (G.) gecko gecko by its smaller SVL (127.1 vs. 161 mm), higher DTR number (16–18 vs. 11–13), different iris color (dark brown vs. pale golden, copper, or brown to olive), absence (vs. usual presence) of a Y-shaped mark on head, and a distinct dorsum background color (dark chocolate brown vs. ultramarine gray to bluish- or brownish-gray). It can be separated from the western Thai Gekko (G.) nutaphandi by its much lower MSR (89–91 vs. 115 or 116), its higher DTR number (16–18 vs. 14), lower PrePo number (11–13 vs. 17–22), higher SubDLT1 (13–16 vs. 12), and higher SubDLT4 (17–19 vs. 15), dark brown (vs. brick red) iris, and dark chocolate brown (vs. grayish brown to chestnut brown) dorsum background color; moreover in Gekko (G.) nutaphandi the white dorsal tubercles are arranged in transverse rows, while they are irregularly distributed in Gekko (G.) pradapdao sp. nov. The new species can be differentiated from the Sino- Vietnamese Gekko (G.) reevesii by its much smaller SVL (127.1 vs. 173 mm), its dark brown (vs. pale golden) iris, absence (vs. presence) of a Y-shaped mark on the head, and its dark chocolate brown dorsum (vs. grayish-brown to grayish-green) with irregularly arranged white tubercles (vs. disposed in transverse rows). From the central Thai Gekko (G.) siamensis it can be distinguished by its generally lower SL number (12–14 vs. 13–21), much lower MSR (89–91 vs. 121–132), its single postcloacal tubercle (vs. two), dark brown (vs. green) iris, and its dark chocolate brown (vs. gray-brown to dark green) dorsum background color with irregularly arranged white tubercles (vs. disposed in transverse rows). It can be differentiated from Gekko (G.) smithii by its much smaller SVL (127.1 vs. 191 mm), lower InterCilS number (24–28 vs. 31–43), higher DTR number (16–18 vs. 8–13), dark brown (vs. green) iris, absence (vs. presence) of a Y-shaped mark on head, and by its dark chocolate brown (vs. yellow-green to dark green) dorsum background color with irregularly arranged white tubercles (vs. disposed in transverse rows). It can be separated from Gekko (G.) verreauxi, endemic to the Andaman Islands, by its smaller SVL (127.1 vs. 155 mm), the contact between its nostril and rostral (vs. no contact), much higher DTR number (16–18 vs. 11), smaller SubDLT4 (17–19 vs. 20–22), dark brown (vs. green) iris, and its dark chocolate brown (vs. gray-brown) dorsum background color.
description: Published as part of Meesook, Worawitoo, Sumontha, Montri, Donbundit, Nattasuda & Pauwels, Olivier S. G., 2021, A new cave-dwelling Gekko (Gekko) from Lopburi Province, central Thailand (Squamata, Gekkonidae), pp. 318-330 in Zootaxa 4969 (2) on pages 319-325, DOI: 10.11646/zootaxa.4969.2.5, http://zenodo.org/record/4749085