Cyrtodactylus meesookae, Sumontha & Panitvong & Kunya & Donbundit & Suthanthangjai & Suthanthangjai & Phanamphon & Pauwels, 2024

Sumontha, Montri, Panitvong, Nonn, Kunya, Kirati, Donbundit, Nattasuda, Suthanthangjai, Winai, Suthanthangjai, Maneerat, Phanamphon, Eakarit & Pauwels, Olivier S. G., 2024, Two new cave-dwelling species of Bent-toed Geckos from Saraburi and Loei provinces, Thailand (Squamata: Gekkonidae: Cyrtodactylus), Zootaxa 5512 (2), pp. 272-294 : 274-281

Cyrtodactylus meesookae sp. nov.

( Figures 1–4)

Holotype. CUMZ-R-2600 (field no. MS 761 ), adult female caught on 27 November 2003 in a cave on Khao Nam Phu (14°34’33.2”N, 101°08’42.6”E), a limestone hill in the village of Thap Kwang , Kaeng Khoi District, Saraburi Province, central Thailand, by Eakarit Phanamphon and Montri Sumontha.

Paratypes (2). CUMZ-R-2601 (field no. MS 762 ), adult female, and CUMZ-R-2602 (field no. MS 763 ), adult male; same locality, date and collectors as holotype .

Diagnosis. Cyrtodactylus meesookae sp. nov. can be distinguished from all other congeneric species by the combination of its maximal known SVL of 87.3 mm, 21–23 interorbital scales, 31–41 interciliary scales, 11 or 12 supralabials, 9–11 infralabials, 31 or 32 paravertebral tubercles of which 23 or 24 between limb insertions, 16–18 longitudinal rows of dorsal tubercles at midbody, 46 ventral scale rows at midbody, poorly defined, non-denticulate ventrolateral folds, no enlarged femoral scales, six precloacal pores (three pores on each side separated by two smaller, poreless scales) in the male, six or seven pits (three or four on each side separated by two or three pitless scales) in females, no precloacal groove or depression, two postcloacal spurs on each side of the base of the tail in males and females, no interdigital webbing, 16–19 total subdigital lamellae on 4th toe, a row of widened median subcaudal plates, a banded dorsal pattern including an uninterrupted nuchal collar and three dark brown bands on dorsum, ten or 11 dark brown bands on original tail, and a golden iris.

Description of the holotype. Adult female ( Figures 1–3). SVL 85.2 mm. TailL 91.6 mm, tail original and complete. Head relatively long (HeadL/SVL ratio 0.31), relatively wide (HeadW/HeadL ratio 0.59), not markedly depressed (HeadD/HeadL ratio 0.38), distinct from slender neck. Loreal region inflated, canthus rostralis not prominent. Snout relatively elongate (SnOrb/HeadL ratio 0.37), rounded, longer than orbit diameter (OrbD/SnOrb ratio 0.80); scales on snout small, rounded to oval, granular, mostly homogeneous, larger than those on crown, interorbital and occipital regions. Eye relatively large (OrbD/HeadL 0.30); pupil vertical with crenelated margins; supraciliaries short, bearing small conical spines. Ear opening vertically elliptical, relatively small (EarL/HeadL 0.05); orbit to ear distance smaller than orbit diameter (OrbEar/OrbD 0.85). Rostral much wider (3.8 mm) than deep (2.0 mm), rostral crease about half of rostral height. Two enlarged supranasals separated from one another by two small superposed scales. Rostral in contact with first supralabials, nostrils, supranasals and internasal. Nostrils oval, more or less laterally directed, each surrounded by supranasal, rostral, first supralabial and three postnasals. Three or four rows of small scales separate orbit from supralabials. Mental triangular, wider (3.2 mm) than deep (2.7 mm). A single pair of greatly enlarged postmentals in broad contact behind mental, each bordered anteromedially by mental, anterolaterally by first infralabial, posterolaterally by an enlarged lateral chinshield; both postmentals collectively bordered posteriorly by four gular scales. Supralabials to mid-orbital position 9/9, enlarged supralabials to angle of jaws 11/11. Infralabials 10/9. Interorbital scale rows across narrowest point of frontal bone 22.

Body slender, relatively short (AG/SVL 0.41; TrunkL 51.6 mm) with poorly defined, non-denticulate ventrolateral folds. Dorsal scales relatively homogeneous, domed; dorsal tubercles five to six times size of adjacent dorsal scales, extending from nape onto tail, smaller tubercles on postocular region, crown, occiput and nape; most tubercles bearing a strong keel, less marked on lower flank tubercles; tubercles in 18 rows at midbody, separated from one another by two to four, but generally three, dorsal granules. Ten to 12 granular dorsal scales surround each tubercle. Ventral scales larger than dorsals, smooth, oval and subimbricate, largest on posterior abdomen and in precloacal region. Midbody scale rows across belly between ventrolateral folds 46. Gular region with homogeneous, smooth, juxtaposed granular scales. No precloacal groove or depression. No enlarged femoral scales; on each side three PrePi separated by two median, smaller, pitless scales. Postcloacal spurs each bearing two enlarged, conical scales.

Scales on palm and sole smooth, rounded to oval or hexagonal, slightly domed. Scalation on dorsal surface of forelimbs without tubercles; surface of hind limbs similar to body dorsum with enlarged tubercles interspersed among smaller scales. Fore and hind limbs relatively long, slender (FaL/SVL 0.18, TibL/SVL 0.22). Digits long, slender, inflected at interphalangeal joints, all bearing robust, slightly recurved claws. Basal subdigital lamellae broad, oval to rectangular, without scansorial surfaces (4-5-6-6-6 left manus, 4-4-5-6-5 right pes); narrow lamellae distal to digital inflection and not including ventral claw sheath: 10-10-12-12-10 (left manus), 9-10-11-13-11 (right pes); no interdigital webbing. Relative lengths of digits: IV>III>V>II>I (manus), IV>V>III>II>I (pes). Tail original and complete, gently tapering to pointed tip, slightly longer than SVL (TailL/SVL ratio 1.08). A single median row of enlarged subcaudals.

In life, dorsal ground color of head brown with dark brown symmetrical marks; ground color of dorsum and limbs light brown. A dark brown continuous nuchal loop, pursuing a dark brown preorbital stripe, connects orbits. Three dark brown bands on dorsum, longer than their light interspace, the anterior one beginning above the shoulder; the anterior and posterior borders of the collar and these brown bands black; numerous black marks on the light interspaces ( Figure 1). Irregular thin, black bars on upper surface of limbs, hands and feet. Background color of anterior part of tail light brown as dorsum, turning to beige posteriorly, with ten dark rings, encircling the tail; irregular black marks on the light interspaces between the dark rings. Iris golden. Supralabials and infralabials white, barred with blackish brown. Throat, venter and undersides of fore- and hind limbs uniformly whitish.

Variation. Main morphometric and meristic characters of the type series are provided in Table 1. Eleven or 12 granular dorsal scales surround each tubercle in the paratypes. The female paratype has a total of seven precloacal pits, four on the left side, three on the right side, separated by three pitless scales. The male paratype shows six precloacal pores, three on each side, separated by two smaller, poreless scales ( Figure 4). The male paratype has a complete, original tail, as does the female holotype, and a TailL/SVL ratio of 1.24, proportionally higher than in the holotype, and 11 dark rings encircling the tail ( Figure 2).

Distribution and natural history. All individuals we observed, including the types, were found within Khao Nam Phu Cave or just outside its entrance. Cyrtodactylus meesookae sp. nov. is a trogloxene species (sensu Jantarit & Ellis 2023) with a karst ecotype (sensu Grismer et al. 2020 a-b, 2021c). It is so far known only from its type-locality ( Figures 5 and 6). Within the cave, we observed it in syntopy with the geckos Gehyra cf. fehlmanni (Taylor) and Gekko siamensis Grossmann & Ulber. Just outside the entrance of the cave, it was found with the geckos Dixonius melanostictus (Taylor) , Hemidactylus frenatus Duméril & Bibron and H. platyurus (Schneider) .

Etymology.The specific epithet honors our friend,the Thai biologist Worawitoo Meesook, lecturer at Rajamangala University of Technology Srivijaya, for her contributions to the knowledge of the fauna of the Kingdom of Thailand. We suggest the following common names: ตุ๊กกายถ้ำเขาน้ำพ (Took-kai-tham-KhaoNamPhu; Thai); Khao Nam Phu Bent-toed Gecko (English) , and Cyrtodactyle de Khao Nam Phu (French).

Comparison to other species. The lack of enlarged femoral scales distinguishes Cyrtodactylus meesookae sp. nov. from C. amphipetraeus Chomdej, Suwannapoom, Pawangkhanant, Pradit, Nazarov, Grismer & Poyarkov (which shows four to seven dark dorsal bands whose length is subequal to the length of the light interspaces), C. angularis (Smith) (three blotches or three pairs of blotches, their length subequal to that of the interspaces; see Figure 13), C. auribalteatus Sumontha, Panitvong & Deein (three regular dorsal bands of subequal length with nearstraight transversal borders between limb insertions), C. cardamomensis Murdoch, Grismer, Wood, Neang, Poyarkov, Ngo, Nazarov, Aowphol, Pauwels, Nguyen & Grismer (three or four regular dark bands between limb insertions, whose length is subequal to that of the light interspaces), C. chanhomeae Bauer, Sumontha & Pauwels (three regular dorsal bands between limb insertions, anterior border of nuchal collar curved, not straight), C. denticulatus Chomdej, Suwannapoom, Pradit, Phupanbai & Grismer (four irregular dark bands between limb insertions, short nuchal collar), C. fluvicavus Grismer, Aowphol, Yodthong, Ampai, Termprayoon, Aksornneam & Rujirawan (very irregular, poorly contrasted, dorsal bands, short nuchal collar), C. interdigitalis Ulber (three dark dorsal bands between limb insertions, shorter than light interspaces, short nuchal collar), C. intermedius Smith (four regular dark bands between limb insertions), C. kulenensis Grismer, Geissler, Neang, Hartmann, Wagner & Poyarkov (two or three dark bands between limb insertions, whose length is subequal to that of the light interspaces), C. kunyai Pauwels, Sumontha, Keeratikiat & Phanamphon (nuchal collar short and interrupted), C. lenya Mulcahy, Thura & Zug (four regular dark bands on dorsum with straight transversal borders), C. monilatus Yodthong, Rujirawan, Stuart, Grismer, Aksornneam, Termprayoon, Ampai & Aowphol (dorsal pattern made of numerous roundish blotches), C. muangfuangensis Sitthivong, Luu, Ha, Nguyen, Le & Ziegler (four bands between limb insertions), C. ngati Le, Sitthivong, Tran, Grismer, Nguyen, Le, Ziegler & Luu (five dark bands between limb insertions), C. oldhami (Theobald) (pattern made of four longitudinal series of white spots), C. papilionoides Ulber & Grossmann (nuchal collar interrupted or at least near-interrupted; see Figure 14), C. phetchaburiensis Pauwels, Sumontha & Bauer (dorsal pattern made of stripes and blotches), C. rivularis Grismer, Aowphol, Yodthong, Ampai, Termprayoon, Aksornneam & Rujirawan (irregular, poorly contrasted, dorsal bands, short nuchal collar), C. rukhadeva Grismer, Suwannapoom, Pawangkhanant, Nazarov, Yushchenko, Naiduangchan, Le, Luu & Poyarkov (three or four dark bands on dorsum, shorter than the lighter interspaces), C. saiyok Panitvong, Sumontha, Tunprasert & Pauwels (three to five irregular, thin dark bands between limb insertions), C. samroiyot Pauwels & Sumontha (light dorsal interspaces nearly immaculate, short nuchal collar), C. thongphaphumensis Grismer, Rujirawan, Chomdej, Suwannapoom, Yodthong, Aksornneam & Aowphol (irregular, poorly contrasted, dorsal bands, short nuchal collar), C. thylacodactylus Murdoch, Grismer, Wood, Neang, Poyarkov, Ngo, Nazarov, Aowphol, Pauwels, Nguyen & Grismer (three or four regular dark bands whose length is subequal to that of the lighter interspaces; posterior border of nuchal loop rounded), C. tigroides Bauer, Sumontha & Pauwels (regular dorsal bands with straight transversal borders), and C. uthaiensis Grismer, Aowphol, Yodthong, Ampai, Termprayoon, Aksornneam & Rujirawan (five dark bands between limb insertions).

Its six PrePo in a discontinuous series and its lack of FemPo in males separate it from C. amphipetraeus (seven to nine PrePo and 10–12 FemPo in males), C. auribalteatus (six PrePo and eight to ten FemPo in males), C. cardamomensis (nine or ten PrePo in a continuous series in males), C. chanhomeae (32–34 FemPrePo in males), C. denticulatus (13 PrePo and 20 FemPo in males), C. fluvicavus (14 or 15 PrePo and 8–11 FemPo in males), C. interdigitalis (14 PrePo and 17 FemPo in males), C. intermedius (eight to ten PrePo in males), C. jarujini Ulber (52–54 FemPrePo in males; dorsal pattern made of numerous irregular blotches), C. kulenensis (nine or ten PrePo), C. kunyai (3 PrePo and 10–12 FemPo in males), C. lenya (no pores in males), C. monilatus (no pores in males), C. muangfuangensis (six PrePo and 15 FemPo in males), C. ngati (13 PrePo and 14 FemPo in males), C. papilionoides (four to six PrePo in a continuous series), C. phetchaburiensis (five PrePo in a continuous series), C. rukhadeva (17 PrePo and 20 FemPo in males), C. saiyok (five PrePo in males), C. samroiyot (seven PrePo in a continuous series), C. sumonthai Bauer, Pauwels & Chanhome (two PrePo in males, short nuchal collar), C. thongphaphumensis (15 PrePo and 12–16 FemPo in males), C. thylacodactylus (seven to nine PrePo in a continuous row), C. tigroides (eight or nine PrePo and 10–14 FemPo in males) and C. uthaiensis (14 PrePo and 12 FemPo in males).