Cyrtodactylus disjunctus, Grismer & Pawangkhanant & Idiiatullina & Trofimets & Nazarov & Suwannapoom & Poyarkov, 2023

Grismer, L. Lee, Pawangkhanant, Parinya, Idiiatullina, Sabira S., Trofimets, Alexei V., Nazarov, Roman A., Suwannapoom, Chatmongkon & Poyarkov, Nikolay A., 2023, A new species of Cyrtodactylus Gray, 1827 (Squamata: Gekkonidae) from the Thai-Malay Peninsula and the independent evolution of cave ecomorphology on opposite sides of the Gulf of Thailand, Zootaxa 5352 (1), pp. 109-136 : 122-131

Cyrtodactylus disjunctus sp. nov.

Figures 6 , 7

urn:lsid:zoobank.org:act:48691E74-8F3B-43C1-BFAE-E5B7552E7147

Suggested English Common Name: Pawang Bent-toed Gecko

Suggested Thai Common Name: ตุ̊กกายสามขีด (Tuk-Kai Sam Kheet)

Type material. Holotype. Adult female, ZMMU Re-17674 (field tag ISS 130), collected from Pawang Valley (6°43’21.1” N, 100°06’21.6” E; at elevation 60 m a.s.l.), Meung Satun , Satun Province, Thailand, on 23 January 2023 by Parinya Pawangkhanant, Sabira S. Idiiatullina, and Thanawut Woranuch.

Diagnosis ( Table 5 ). Cyrtodactylus disjunctus sp. nov. is potentially separated from all other species of the intermedius group by having 12 supralabials; 11 infralabials; 41 small, rounded, smooth, paravertebral tubercles; 11 rows of small, rounded, smooth, longitudinally arranged tubercles; 36 ventrals; eight expanded subdigital lamellae, nine unexpanded subdigital lamellae, and 17 total subdigital lamellae on the fourth toe; 21 enlarged femorals; 10 enlarged precloacals; nine pitted precloacal scales; one rows of enlarged post-precloacals; one postcloacal tubercle; enlarged femorals and enlarged precloacals not continuous; proximal femorals less than one-half size of distal femorals; body tubercles smooth, greatly reduced; no pocketing between digits; subdigital toe lamellae expanded far beyond body of digit; maximum SVL 66.7; faded dorsal pattern; no dark-colored pigmented blotches on top of head; no dark-colored band on nape; three straight-edged dark-colored dorsal bands lacking lightened centers, thinner than light-colored interspaces between bands, not bordered by prominent white tubercles; no dark-colored markings interspaces; no dark-colored bands or white tubercles on limbs; and 11 dark-colored and light-colored caudal bands.

Description of holotype ( Figs. 6 , 7 ; Table 5 ). Adult female SVL 66.7 mm; head moderate in length (HL/ SVL 0.28), width (HW/HL 0.64), flattened (HD/HL 0.39), distinct from neck, triangular in dorsal profile; lores weakly concave anteriorly, weakly inflated posteriorly; prefrontal region concave; canthus rostralis rounded; snout elongate (ES/HL 0.40), flat, rounded in dorsal profile; eye large (ED/HL 0.29); ear opening elliptical, obliquely oriented, moderate in size; eye to ear distance slightly greater than diameter of eye; rostral rectangular, partially divided dorsally by inverted Y-shaped furrow, bordered posteriorly by large left and right supranasals and one small azygous internasal, bordered laterally by first supralabials; external nares bordered anteriorly by rostral, dorsally by large supranasal, posteriorly by two moderately sized postnasals, bordered ventrally by first supralabial; 12(R,L) rectangular supralabials extending to below midpoint of eye, second–fifth supralabials slightly larger than first; 11(R,L) infralabials tapering smoothly to slightly past the termination of enlarged supralabials; scales of rostrum and lores flat, slightly larger than granular scales on top of head and occiput; scales of occiput intermixed with small, rounded, tubercles; superciliaries elongate, largest anteriorly; mental triangular, bordered laterally by first infralabials and posteriorly by large left and right trapezoidal postmentals contacting medially for ~50% of their length posterior to mental; one row of slightly enlarged, elongate sublabials extending posteriorly to fifth infralabial; gular and throat scales small, granular, grading posteriorly into slightly larger, flatter, smooth, imbricate, pectoral and ventral scales.

Body relatively long (AG/SVL 0.50) with well-defined ventrolateral folds; dorsal scales small, granular, interspersed with small, smooth, rounded, semi-regularly arranged tubercles extending from top of head onto base of tail but no farther; approximately 11 longitudinal rows of tubercles at midbody; approximately 41 paravertebral tubercles; 36 flat, imbricate, ventral scales much larger than dorsal scales; 10 enlarged precloacal scales, nine bearing pits; no deep precloacal groove or depression; and one row of large post-precloacal scales on midline.

Forelimbs thin, relatively long (FL/SVL 0.17); lacking tubercles, granular scales of forelimbs slightly larger than those on body; palmar scales rounded, slightly raised; digits well-developed, inflected at basal interphalangeal joints, slightly narrower distal to inflections; subdigital lamellae transversely expanded, those proximal to joint inflections much wider than those distal to inflections; claws well-developed, sheathed by a dorsal and ventral scale; hind limbs thin, wider than forelimbs, long (TBL/SVL=0.21), covered dorsally by granular scales not interspersed with tubercles, larger and flat anteriorly; ventral scales of thighs flat, imbricate, larger than dorsals; subtibial scales large, flat, imbricate; one row of 11(R)10(L) enlarged femoral scales terminating distally before knee, not continuous with enlarged precloacal scales; proximal femorals much smaller than distal femorals, the latter forming an abrupt union with smaller, rounded, ventral scales of posteroventral margin of thigh; femoral pores absent; plantar scales flat; digits well-developed, inflected at basal interphalangeal joints; basal subdigital lamellae greatly expanded transversely, extending well-beyond body of digit, claws well-developed, sheathed by a dorsal and ventral scale at base; and eight(R,L) wide proximal subdigital lamellae on fourth toe, nine(R,L) more narrow lamellae distal to joint inflection, 17 total subdigital lamellae.

Original tail long (TL/SVL 1.42), thin, 94.8 mm in length, 3.8 mm wide at base, tapering to a point; dorsal caudal scales small, generally square; median row of subcaudals significantly larger than dorsal caudals, transversely expanded, not extending up onto lateral side of tail; body tubercles not extending beyond base of tail; no hemipenal swelling at base of tail, one large postcloacal tubercle on either side; and postcloacal scales flat, imbricate.

Coloration in life ( Fig. 8 ). Ground color of top of head, limbs, and dorsum light-brown; top of head immaculate; straight-edged, dark-brown, nuchal loop extends from posterior margin of one orbit to posterior margin of other orbit; no dark-colored banding on nape; three dark-brown, immaculate, straight-edged, dorsal body bands terminating above the ventrolateral folds extending from shoulders to pelvis, dark-colored body bands narrower than light-colored immaculate interspaces, not edged with light-colored tubercles; one dark-colored sacral band; limbs brown, immaculate; 11 wide, dark-brown caudal bands slightly wider than 11 light-colored caudal bands; all caudal bands immaculate, posterior caudal bands encircle tail; iris gold, bearing thin, black reticulations; venter beige with faint, dark mottling on lateral edges of belly, undersides of limbs; and subcaudal region dark-brown.

Etymology. The new species name “ disjunctus ” is a Latin adjective in the nominative singular, masculine gender, meaning “dijunct”, “remote”, and is given in reference to the approximately 600 km wide hiatus across the Gulf of Thailand separating Cyrtodactylus disjunctus sp. nov. from the other members of the intermedius group in central Indochina.

Comparisons ( Table 3 ). Cyrodactylus disjunctus sp. nov. differs from all other members of the intermedius group by having greatly expanded transverse subdigital lamellae on the hind feet and a unique dorsal banding pattern. With the exception of C. hontreensis , C. disjunctus sp. nov. differs from all other members of the intermedius group by having immaculate patterned limbs. Cyrtodactylus disjunctus sp. nov. is potentially widely separated from all other members of the intermedius group (n=1) by scale counts and morphometrics ( Table 3 ; Murdoch et al. 2019; Grismer et al. 2020b, 2021c). Cyrtodactylus disjunctus sp. nov. resembles C. hontreensis in having a cave-adapted morphology and color pattern ( Fig. 8 ; sec Grismer et al. 2021b) but differs from it by having thinner dark-colored body bands that lack lightened centers not edged with white tubercles. Furthermore, C. disjunctus sp. nov. has darkand light-colored caudal bands as opposed to lacking them. Cyrodactylus disjunctus sp. nov. does not overlap with any other species along the statistically significant axes of all four multivariate plots ( Figs. 3 , 4 ) and has a pairwise sequence divergence from the mean divergences of the other species ranging from 17.9–23.6% ( Table 1 ).

Natural history ( Fig. 9 .) The holotype was collected between 19–23:00 h in a karst forest comprised of Bombax anceps (Malvaceae) at 60 m in elevation. It was sitting on a karstic boulder near the cave wall 2 m above the ground 1 m away from the cave entrance. A juvenile was seen by a ranger during this period in the Wang Raya area within a limestone cave along a limestone hill covered with lowland dipterocarp forest in the Tha Le Ban Range. Currently, Cyrtodactylus disjunctus sp. nov. is known only from the karst formation of the Tha Le Ban range in Wang Prachan District, Satun Province near the Thai-Malaysian border. Its occurrence in Perlis State, Peninsular Malaysia is strongly anticipated, similar to recently confirmed new population of C. zebriacus Taylor, 1962 ( Quah et al. 2023) from Perlis State, Malaysia. Other species recorded at same site included: Ingerophrynus parvus (Bufonidae) , Micryletta lineata , Microhyla butleri , Kaloula latidisca (Microhylidae) , Cnemaspis biocellata , Gekko gecko , Cyrtodactylus astrum (Gekkonidae) , Elaphe taeniura (Colubridae) , and Tropidolaemus wagleri (Viperidae) .

Figures

FIGURE 3. PCAs and DAPCs, respectively of A and D meristic, B and D morphometric, and C and E meristic-morphometric datasets. F Statistically significant variation based the permutation and bootstrap analyses conducted in the PCAtest. F PC 1of the meristic data set. G PCs 1 and 2 of the morphometric dataset. H PCs 1 and 2 of the meristic-morphometric dataset.

FIGURE 4. A MFA of the species of the Cyrtodactylus intermedius group. B Percent contributions of each data type to the inertia of dimensions 1–4 of the MFA. Percentage values on the bar graphs are the amounts of inertia for the respective dimensions. The red line represents the value if all contributions were equal. C The percent contribution of each character to dimensions 1–3. The red line represents the value if all contributions were equal.

FIGURE 6. A Dorsal and ventral views of the holotype of Cyrtodactylus disjunctus sp. nov. ISS 130 ZMMU re-17674 from Meung Satun, Satun Province, Thailand. B Photo of the holotype in life. Photographs by Parinya Pawangkhanan.

FIGURE 7. Holotype of Cyrtodactylus disjunctus sp. nov. ISS 130 ZMMU re-17674 from Meung Satun, Satun Province, Thailand. A Dorsal view of head. B right lateral view of head. C Gular region. D Ventral view of hand. E Ventral view of foot. F Ventral view of femora and precloacal region. G Subcaudal region. Photographs by Parinya Pawangkhanan.

FIGURE 8. Differences in body shape of the thinner cave-adapted species Cyrotactylus disjuntus sp. nov. ISS 130 ZMMU re-17674, C. hontreensis UNSM0216, and C. laangensis LSUDPC 4021 A, C, and E, respectively in comparison to the more robust species that are not adapted to living in caves, B C kohrongensis LSUHC 10536 D C. thylacodactylus LSUDPC 5080 and F C. cardamomensis LSUDPC 6080. Photographs by Parinya Pawangkhanan A; L. Lee Grismer B, D, and F; Ngo Van Tri C, and Jeremy Holden E.

FIGURE 9. Forest habitat at the type locality of Cyrotactylus disjunctus sp. nov. ISS 130 from Meung Satun, Satun Province, Thailand. Photograph by Parinya Pawangkhanan.