Cyrtodactylus kochangensis, Grismer & Aowphol & Yodthong & Ampai & Termprayoon & Aksornneam & Rujirawan, 2022

Grismer, L. Lee, Aowphol, Anchalee, Yodthong, Siriporn, Ampai, Natee, Termprayoon, Korkhwan, Aksornneam, Akrachai & Rujirawan, Attapol, 2022, Integrative taxonomy delimits and diagnoses cryptic arboreal species of the Cyrtodactylus brevipalmatus group (Squamata, Gekkonidae) with descriptions of four new species from Thailand, ZooKeys 1129, pp. 109-162 : 109

Cyrtodactylus kochangensis sp. nov.

Fig. 10 Suggested Common Name: Ko Chang Bent-toed Gecko

Holotype.

Adult female ZMKU R 00945 from Ko Chang Island, Ko Phayam Subdistrict, Mueang Ranong District, Ranong Province, Thailand (9.82411°N, 98.43999°E, 36 m a.s.l.), collected by Siriporn Yodthong, Natee Ampai, Attapol Rujirawan, and Piyawan Puanprapai on 8 July 2017.

Additional material examined.

Cyrtodactylus cf. kochangensis sp. nov. adult male THNHM 01667 from Khlong Naka Wildlife Sanctuary , Suk Samran District, Ranong Province, Thailand (~ N 9.4596, E 98.5044, elevation unknown), collected by Yodchaiy Chuaynkern between 28 December 2000 and 2 January 2001 .

Diagnosis

(based on the holotype). Cyrtodactylus kochangensis sp. nov. can be separated from all other species of the Cyrtodactylus brevipalmatus group by the combination of having 12 or 13 supralabials, nine infralabials, 34 paravertebral tubercles, 14 rows of longitudinally arranged tubercles, 35 transverse rows of ventrals, 172 longitudinal rows of ventrals, 8 or 9 expanded subdigital lamellae on the fourth toe, 11 or 12 unexpanded subdigital lamellae on the fourth toe, 19-21 total subdigital lamellae on the fourth toe; eight expanded subdigital lamellae on the fourth finger, ten unexpanded subdigital lamellae on the fourth finger, 18 total subdigital lamellae on the fourth finger; 12 total enlarged femoral scales; 12 enlarged precloacal scales; enlarged femoral and enlarged precloacal scales not continuous; proximal femoral scales less than one-half the size of the distal femorals; small tubercles on forelimbs and flanks; large dorsolateral caudal tubercles and a wide ventrolateral caudal fringe not composed homogeneous scales; tail square in cross-section; slightly enlarged paired medial subcaudals not posteromedially furrowed; maximum SVL 60.1 mm; five dark transverse body bands (Tables 4 , 5 ).

Description of holotype

(Fig. 10 ). Adult female SVL 60.1 mm; head moderate in length (HL/SVL 0.29), width (HW/HL 0.67), depth (HD/HL 0.38), distinct from neck, triangular in dorsal profile; lores flat anteriorly, weakly inflated posteriorly; prefrontal region slightly concave; canthus rostralis rounded; snout elongate (ES/HL 0.40), rounded in dorsal profile; eye large (ED/HL 0.24); ear opening subcircular, small; eye to ear distance greater than diameter of eye; rostral rectangular, furrowed dorsally, bordered posteriorly by large left and right supranasals and one slightly smaller azygous internasal, bordered laterally by first supralabials; external nares bordered anteriorly by rostral, dorsally by large supranasal, posteriorly by two slightly smaller postnasals, bordered ventrally by first supralabial; 12R/13L rectangular supralabials tapering smoothly to below eye; 9R/9L infralabials tapering smoothly to below eye; scales of rostrum and lores domed, slightly larger than granular scales on top of head and occiput; scales of occiput intermixed with distinct, small tubercles; superciliaries subrectangular, largest anteriorly; mental triangular, bordered laterally by first infralabials and posteriorly by large left and right trapazoidal postmentals contacting medially for approximately 40% of their length posterior to mental; one row of six (R,L) slightly enlarged sublabials extending posteriorly fifth infralabials, subsequent sublabials much smaller; gular and throat scales small, granular, grading posteriorly into slightly larger, flatter, smooth, imbricate, pectoral and ventral scales.

Body relatively short (AG/SVL 0.48) with well-defined ventrolateral folds; dorsal scales small, granular, interspersed with larger conical, semi-regularly arranged, weakly keeled tubercles; tubercles extend from occipital region onto base of tail and slightly beyond as paravertebral rows; tubercles of nape and occiput smaller than those on body; approximately 14 longitudinal rows of tubercles at midbody; approximately 34 paravertebral tubercles; tubercles on upper flanks smaller than those on dorsum; approximately 35 longitudinal rows of flat, imbricate, ventral scales much larger than dorsal scales; approximately 172 transverse rows of ventral scales; no pore-bearing, precloacal scales; 12 enlarged precloacal scales; no deep precloacal groove or depression; and approximately three rows of post-precloacal scales on midline.

Forelimbs moderate in stature, relatively short (ForL/SVL 0.13); granular scales of forearm slightly larger than those on body, interspersed with tubercles; palmar scales rounded, slightly raised; digits well-developed, relatively short, inflected at basal interphalangeal joints; digits narrower distal to inflections; subdigital lamellae wide, transversely expanded proximal to joint inflections, narrower transverse lamellae distal to joint inflections; claws well-developed, claw base sheathed by a dorsal and ventral scale; 8R/8L expanded and 10R/10L unexpanded lamellae beneath the fourth finger; hind limbs larger and thicker than forelimbs, moderate in length (TibL/SVL 0.14), covered dorsally by granular scales interspersed with moderately sized, conical tubercles dorsally and posteriorly and anteriorly by flat, slightly larger, subimbricate scales; ventral scales of thigh flat, subimbricate, larger than dorsals; subtibial scales flat, imbricate; no pore-bearing femoral scales; 6R/6L enlarged femoral scales; enlarged femoral scales not contiguous with enlarged precloacal scales, terminating distally at knee; proximal femoral scales smaller than distal femorals, the former forming an abrupt union with much smaller, rounded, ventral scales of posteroventral margin of thigh; plantar scales flat; digits relatively long, well-developed, inflected at basal interphalangeal joints; 9R/8L wide, transversely expanded subdigital lamellae on the fourth toe proximal to joint inflection that extend onto sole, and 12R/11L unexpanded lamellae beneath the fourth toe; and claws well-developed, sheathed by a dorsal and ventral scale at base.

Tail original (but in two pieces), long 80.3 mm (TL/SVL 1.34), 4.0 mm in width at base, tapering to a point; nearly square in cross-section; dorsal scales flat, square bearing tubercles forming paravertebral rows and large tubercles forming a dorsolateral longitudinal row; slightly larger, posteriorly directed, semi-spinose tubercles forming wide distinct ventrolateral caudal fringe; scales of ventrolateral fringe generally interspersed at regular intervals with larger spinose scales; medial subcaudal scales paired, slightly enlarged; subcaudals, larger than dorsal caudal scales; base of tail bearing hemipenial swellings; one conical postcloacal tubercle at base of hemipenial swellings; and postcloacal scales flat, imbricate.

Coloration in life

(Fig. 10 ). Ground color of the head, body, limbs, and tail pale brown; faint, diffuse mottling on rostrum; lores darkly colored; wide, distinct, pale-colored postorbital stripe; nuchal band faint, bearing two posterior projections; three very faint, wide, irregularly shaped body bands between limb insertions edged in slightly darker brown; band interspaces bearing irregularly shaped, faint, dark-colored markings; dark-colored speckling on limbs and digits; digits bearing pale-colored bands; four wide, faint, dark-colored caudal bands separated by three pale-colored bands on original portion of tail; all caudal bands encircle tail; all ventral surfaces beige, generally immaculate; and iris orangish to coppery in color.

Variation.

The additional specimen (THNHM 01667) closely approximates the holotype in overall coloration and pattern except that it is more boldly marked. It has four dark-colored body bands as opposed to three and a complete original tail bearing eight dark-colored and seven pale-colored bands. The pale-colored postorbital stripe is slightly thinner and less distinct. Meristic and morphometric differences are listed in Table 5 . Given its overall morphological and color pattern similarities and close geographic proximity to the holotype (~ 40 km), we consider this individual as C. cf. kochangensis sp. nov. pending genetic data.

Distribution.

Cyrtodactylus kochangensis sp. nov. is currently known only from the type locality at Ko Chang Island, Ko Phayam Subdistrict, Mueang Ranong District, Ranong Province, Thailand. The additional population of pending species status occurs in the Khlong Naka Wildlife Sanctuary, Suk Samran District Ranong Province.

Etymology.

The specific epithet kochangensis is in reference to the type locality, Ko Chang, Ranong Province, Thailand

Comparisons

(based on the holotype). Cyrtodactylus kochangensis sp. nov. forms a clade with the sister species Cyrtodactylus rivularis sp. nov. and C. rukhadeva (Fig. 2 ) from which it differs by an uncorrected pairwise sequence divergence of 12.00-12.52% and 12.52-13.68%, respectively (Table 2 ) and it and C. cf. kochangensis sp. nov. are separated from C. rukhadeva and Cyrtodactylus rivularis sp. nov. by geographic distance of no less than ~280-470 km (Fig. 1 ). The small sample size (N = 1) precludes it from statistical analyses, however at this point, it differs from C. rukhadeva and C. cf. rukhadeva in having 34 PVT versus 26-30; 14 LRT versus 18-20; 172 VSM versus 152-165; 12 FS versus 13-18; 12 PCS versus 13-17 and 1 PCT versus 2 or 3, collectively. From C. rukhadeva by having 12 FS versus 16 or 17; and five BB versus three. From Cyrtodactylus rivularis sp. nov. it differs in having 14 LRT versus 18-20; 172 VSM versus 160-166; 12 FS versus 14-16; and five BB versus three or four. Discrete differences between Cyrtodactylus kochangensis sp. nov. and C. cf. kochangensis sp. nov. and all other species and populations are presented in Tables 4 , 5 .

Natural history.

The holotype (ZMKU R 00945) was collected at night (2107 h) among branches of a small tree approximately 100 cm above the ground at 36 m elevation with a temperature of 28.6 °C and relative humidity of 83.9%. The surrounding habitat was dry evergreen forest with a rocky stream nearby (Fig. 11 ). The new species was found to co-occur with two other species of gekkonid lizards, Cyrtodactylus oldhami (Theobald, 1876) and Gekko tokehos (Grismer, Wood, Grismer, Quah, Thy, Phimmachak, Sivongxay, Seateun, Stuart, Siler, Mulcahy, Anamza & Brown, 2019).

Figures

Figure 1. Distribution of nominal species and unnamed populations and specimens of the Cyrtodactylus brevipalmatus group. Stars denote type localities. White circles are literature localities from which specimens were not examined and remain unidentified. Locality data for all material examined is in Table 1.

Figure 2. Maximum clade credibility BEAST phylogeny of the Cyrtodactylus brevipalmatus group highlighting the new species described herein. Bayesian posterior probabilities (BPP) are listed at the nodes.

Figure 10. Holotype of Cyrtodactylus kochangensis sp. nov. ZMKU R 00945 (field no. AA 04439) from Thailand, Ranong Province, Mueng Ranong District, Ko Phayam Subdistrict, Ko Chang A dorsal view B ventral view C dorsal view of head D ventral view of femoral and precloacal regions E dorsal view of tail F ventral view of tail G holotype in life.

Figure 11. Habitat of Cyrtodactylus kochangensis sp. nov. at Thailand, Ranong Province, Mueng Ranong District, Ko Phayam Subdistrict, Ko Chang.