Cyrtodactylus rukhadeva, Grismer & Suwannapoom & Pawangkhanant & Nazarov & Yushchenko & Naiduangchan & Le & Luu & Poyarkov, 2021

Grismer, L. Lee, Suwannapoom, Chatmongkon, Pawangkhanant, Parinya, Nazarov, Roman A., Yushchenko, Platon V., Naiduangchan, Mali, Le, Minh Duc, Luu, Vinh Quang & Poyarkov, Nikolay A., 2021, A new cryptic arboreal species of the Cyrtodactylus brevipalmatus group (Squamata: Gekkonidae) from the uplands of western Thailand, Vertebrate Zoology 71, pp. 723-746 : 723

Cyrtodactylus rukhadeva sp. nov.

Figures 7 , 8

Cyrtodactylus brevipalmatus Ulber 1993:198 (partim).

Holotype.

Adult male ZMMU R-16851 (field tag NAP-09743, tissue sample ID HLM0372) from Thailand, Ratchaburi Province, Suan Phueng District, Khao Laem Mountain (13.53846N, 99.20071E, elevation 994 m a.s.l.), collected by Platon V. Yushchenko and Kawin Jiaranaisakul on 19 June 2019.

Paratype.

Adult female ZMMU R-16852 (field tag NAP-09744) from Thailand, Ratchaburi Province, Suan Phueng District, Hoop Phai Tong (13.56210N, 99.20670E, elevation 593 m a.s.l.), collected by Platon Yushchenko on 11 July 2019.

Diagnosis.

Cyrtodactylus rukhadeva sp. nov. can be separated from all other species of the Cyrtodactylus brevipalmatus group by having 9-11 supralabials, 10 or 11 infralabials, 27-30 paravertebral tubercles, 19 or 20 rows of longitudinally arranged tubercles, 34-43 transverse rows of ventrals, 152-154 longitudinal rows of ventrals, nine expanded subdigital lamellae on the fourth toe, 11 unexpanded subdigital lamellae on the fourth toe, 18-20 total subdigital lamellae on the fourth toe, eight or nine expanded subdigital lamellae on the fourth finger, nine or 10 unexpanded subdigital lamellae on the fourth finger, 17-19 total subdigital lamellae on the fourth finger, 16-17 enlarged femorals, 20 femoral pores in the male; 17 precloacal pores in the male; 13-17 enlarged precloacals; 16 post-precloacals; enlarged femorals and enlarged precloacals not continuous; proximal femorals not less than one-half the size of the distal femorals; small tubercles on forelimbs and flanks; small dorsolateral caudal tubercles and ventrolateral caudal fringe; paired enlarged subcaudals; and maximum SVL 79.4 mm (Tables 1 , 4 ).

Description of holotype.

(Figs 7 and 8 ) Adult male SVL 74.9 mm; head moderate in length (HL/SVL 0.27), width (HW/HL 0.72), depth (HD/HL 0.46), distinct from neck, triangular in dorsal profile; lores concave slightly anteriorly, weakly inflated posteriorly; prefrontal region slightly concave; canthus rostralis rounded; snout elongate (ES/HL 0.41), rounded in dorsal profile; eye large (ED/HL 0.23); ear opening round, small; eye to ear distance 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 smaller postnasals, bordered ventrally by first supralabial; 11(R,L) rectangular supralabials extending to below midpoint of eye, second supralabial same size as first; 10(R,L) infralabials tapering smoothly to just below and slightly past posterior margin of eye; scales of rostrum and lores flat to domed, larger than granular scales on top of head and occiput; scales of occiput and interorbital region intermixed with distinct, small tubercles; superciliaries subrectngular, largest anteriorly; mental triangular, bordered laterally by first infralabials and posteriorly by large left and right trapezoidal postmentals contacting medially for 60% 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 short (AG/SVL 0.46) with defined ventrolateral folds; dorsal scales small, granular interspersed with larger, conical, semi-regularly arranged, moderately keeled tubercles; tubercles extend from interorbital region onto base of tail; smaller tubercles extend anteriorly onto nape and occiput, diminishing in size and distinction in interorbital region; approximately 19 longitudinal rows of tubercles at midbody; approximately 27 paravertebral tubercles; 34 longitudinal rows of flat, imbricate, ventral scales much larger than dorsal scales; 153 transverse rows of ventral scales; 17 large, pore-bearing, precloacal scales; no deep precloacal groove or depression; and nine rows of post-precloacal scales on midline.

Forelimbs moderate in stature, relatively short (ForL/SVL 0.11); granular scales of forearm slightly larger than those on body, interspersed with small 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; nine expanded and 11 unexpanded lamellae beneath first finger; hind limbs more robust than forelimbs, moderate in length (TibL/SVL 0.13), covered dorsally by granular scales interspersed with moderately sized, conical tubercles and anteriorly by flat, slightly larger scales; ventral scales of thigh flat, subimbricate, larger than dorsals; subtibial scales flat, imbricate; one row of 9,8(R,L) enlarged femoral scales not continuous with enlarged precloacal scales, terminating distally at knee; proximal femoral scales smaller than distal femorals, the latter forming an abrupt union with smaller, rounded, ventral scales of posteroventral margin of thigh; 8,9(R,L) femoral pores; plantar scales flat; digits relatively long, well-developed, inflected at basal interphalangeal joints; 8(R,L) wide, transversely expanded subdigital lamellae on fourth toe proximal to joint inflection that extend onto sole; nine expanded and 10 unexpanded lamellae beneath first toe; and claws well-developed, sheathed by a dorsal and ventral scale at base.

Tail long (TL/SVL 1.29) 6.8 mm in width at base, tapering to a point; dorsal scales flat, square bearing tubercles forming paravertebral rows and slightly larger tubercles forming a dorsolateral longitudinal row; enlarged, posteriorly directed semi-spinose tubercles forming small but distinct ventrolateral caudal fringe; median row of paired, transversely expanded subcaudal scales, larger than dorsal caudal scales; base of tail bearing hemipenal swellings; three conical postcloacal tubercles at base of hemipenal swellings; and postcloacal scales flat, imbricate.

Coloration in life (Fig. 8).

Ground color of the head body, limbs, and tail brown; faint, diffuse mottling on the top of the head; wide, dark-brown post-orbital stripe; lores dark- brown; nuchal band faint, bearing two posterior projections; three wide faint body bands edged in dark-brown between limb insertions; band interspaces bearing irregularly shaped, dark markings; faint dark speckling on limbs and digits; five wide slightly darker caudal bands separated by five lighter caudal bands; posterior tip of regenerated tail unbanded; ventral surfaces beige, generally immaculate; gular region lacking pigment; poaterior subcaudal region faintly banded; iris orangish gold in color.

Variation (Fig. 8).

The female paratype differs significantly from the male holotype in coloration and pattern. The holotype has a much less contrasting dorsal pattern with only faint indications of dorsal body and caudal bands whereas the paratype is boldly marked, bearing a one dark jagged-edged nuchal band and three dark jagged-edged body bands, all with darkened borders. The caudal pattern of the paratype consists of six dark and seven light-colored contrasting bands on a full original tail whereas the holotype has four dark and light-colored weakly contrasting bands and a regenerated tail tip. The top of the head of the holotype is essentially unicolor whereas that of the paratype is darkly mottled. With only one specimen of each sex we cannot say if these differences in color pattern are sexually dimorphic. An uncataloged juvenile had a generally unicolor tan dorsal ground color overlain with a dark-brown nuchal loop bearing two posteriorly oriented projections, four complete to incomplete dark-brown body bands, and nine dark-brown caudal bands separated by eight tan to white caudal bands (Fig. 8 )

Distribution.

Cyrtodactylus rukhadeva sp. nov. is known only from the type locality from Khao Laem Mountain, Suan Phueng District, Ratchaburi Province, Thailand and Hoop Phai, Suan Phueng District, Ratchaburi Province, approximately 7.7 km to the west of the type locality (Fig. 1 ).

Etymology.

The specific epithet " Cyrtodactylus rukhadeva " is given as a noun in apposition and refers to the spirits or gods residing in trees in Thai mythology, known as Rukha Deva (literally "Tree Nymphs"). According to Thai folklore, these sylvan spirits live on tree branches and on large older trees wearing traditional Thai attire, usually in reddish or brownish colours, and are believed to protect the forest. The new arboreal species of Cyrtodactylus resides in one of the remaining fragments of the north Tenasserim montane forests. We want to underscore the need for the immediate assessment of herpetofaunal diversity surveys and implementation of adequate conservation measures for these relic forests.

Comparisons.

Given the low sample size (n=2) of Cyrtodactylus rukhadeva sp. nov., meaningful statistical comparisons of meristic were not possible. However, some character ranges-at this point-are diagnostic in that they are widely separated from one another. We are well aware that a larger sample size may preclude some of these characters as being diagnostic but it is equally probable that they will demonstrate that they are truly diagnostic. Cyrtodactylus rukhadeva sp. nov. can be separated from C. ngati in having fewer paravertebral tubercles (PVT; 27-30 vs 38-40), from C. elok in having more longitudinal rows of dorsal tubercles (LRT; 19 or 20 vs 4-7), from C. brevipalmatus and C. elok in having fewer transverse rows of ventral scales (VSM; 152-154 vs 172-180 and 190-234, respectively), from C. brevipalmatus in having more enlarged femoral scales (FS; 16 or 17 vs 10-16), from all species in having more femoral pores in males (FP; 20 vs 0-17 collectively), from C. cf. interdigitalis , C. brevipalmatus , and C. elok in having males having more precloacal pores (PP; 17 vs 13, 7, and 8, respectively), and from all species except C. elok in having more post-precloacal scales (PPS; 16 vs 2-10, cllectively. All ranges are presented in Table 5 . Summary statistics and comparisons among the adjusted morphometric characters are presented in Table 6 .

Cyrtodactylus rukhadeva sp. nov. can be readily separated from all other species on the basis of discrete morphological differences (Table 4 ). Cyrtodactylus rukhadeva sp. nov. has paravertebral tubercles and enlarged femoral scales which are absent in C. elok . Cyrtodactylus rukhadeva sp. nov. has small tubercles on the forelimbs which are absent in C. cf. interdigitalis , C. ngati , and C. elok . Cyrtodactylus rukhadeva sp. nov. has small tubercles on the flanks, femoral pores in males, enlarged dorsolateral tubercles, and a large ventrolateral caudal fringe that are absent in C. elok . Cyrtodactylus rukhadeva sp. nov. has a square tail in cross-section versus a round tail in C. cf. interdigitalis , C. ngati , and C. brevipalmatus . Cyrtodactylus rukhadeva sp. nov. has single enlarged subcaudal scales versus paired enlarged subcaudal scales in C. cf. interdigitalis and C. brevipalmatus . Cyrtodactylus elok and C. ngati lack distinctly enlarged subcaudal scales. Cyrtodactylus rukhadeva sp. nov. has a prehensile tail apparently lacking in C. ngati . Figure 9 illustrates the general morphological and color pattern similarity of the other members of the Cyrtodactylus brevipalmatus group to C. rukhadeva sp. nov.

Natural History.

Cyrtodactylus rukhadeva sp. nov. inhabits montane and submontane evergreen polydominant tropical forests, and was most often recorded in bamboo forests mixed with dry dipterocarp forests at elevations ranging from 600 to 1100 m a.s.l. and dominated by the large trees Anisoptera costata Korth, 1841 and Dipterocarpus gracilis Blume, 1825 ( Dipterocarpaceae ) (Fig. 10A ). Lizards were usually observed near large tree holes or hiding among the roots of strangler fig trees ( Ficus sp.; Moraceae ) (Fig. 10B ). All were active from approximately 19:30-23:50 hrs and approximately 2 m above the ground. One lizard was observed ca. 6 m above the ground on the branch of Syzygium sp. ( Myrtaceae ) above a rocky streambed. Given its morphology, we believe C. rukhadeva sp. nov. is an arboreal specialist that generally resides in the upper canopy, but may be forced down to lower portions of the canopy or to the understory layer by rain storms or strong winds. Gravid females bearing two eggs were recorded in March; two eggs of the new species were found attached in a tree hole; total length of the hatchlings was approximately 7 cm. Cyrtodactylus rukhadeva sp. nov. is a highly aggressive species that opens its mouth and waves its tail from side to side in a defensive posture when threatened. At the type locality, C. rukhadeva sp. nov. was recorded in sympatry with Cnemaspis selenolagus Grismer, Yushchenko, Pawangkhanant, Nazarov, Naiduangchan, Suwannapoom & Poyarkov, 2020, Cyrtodactylus cf. oldhami (Theobald, 1876), and Gekko (Ptychozoon) kaengkrachanense (Sumontha, Pauwels, Kunya, Limlikhitaksorn, Ruksue, Taokratok, Ansermet & Chanhome, 2012).

Figures

Figure 1. Distribution of the species of the Cyrtodactylus brevipalmatus group. Stars = type localities and squares refer to literature records. White squares denote unexamined specimens of uncertain taxonomic status. Localities with specimen numbers denote individuals in the phylogeny (Fig. 2). No topotypic material (red) from the western Phetchabun massif was examined. NP = National Park and WS = Wildlife Sanctuary.

Figure 7. A. Dorsal view of the head of the holotype of Cyrtodactylus rukhadeva sp. nov. (ZMMU R- 16851) from Khao Laem Mountain, Suan Phueng District, Ratchaburi Province, Thailand. B. Gular region of the holotype. C. Right lateral view of the head of the holotype. D. Pores in the femoral and precloacal region of the holotype. E. Dorsal views of the holotype (left) and paratype (ZMMU R- 16852) from Hoop Phai Tong, Suan Phueng District, Ratchaburi Province, Thailand. F. Subcaudal region of the holotype showing the single median row of transversely enlarged subcaudal scales. G. Dorsal view of body showing the tubercles intermixed with granular scales. Photos by Roman A. Nazarov.

Figure 8. In life coloration and pattern of (A) the paratype of Cyrtodactylus rukhadeva sp. nov. (ZMMU R- 16852) from Hoop Phai Trong, Suan Phueng District, Ratchaburi Province, Thailand and (B) the holotype (ZMMU R- 16581) from Khao Laem Mountain, Suan Phueng District, Ratchaburi Province, Thailand. Photos by Platon V. Yushchenko. C. In life coloration and pattern of a hatchling of Cyrtodactylus rukhadeva sp. nov. (not collected); photo by Mali Naiduangchan.

Figure 9. Illustration showing the general similarity body shape and color pattern among five species of the Cyrtodactylus brevipalmatus group. A. Adult female C. elok (LSUDPC 2589) from Negeri Sembian, Peninsular Malaysia. Photo by L. Lee Grismer. B Adult male sp. 11 (ZMMU R- 16492) from Phu Hin Rong Kla National Park, Petchabun Province, Phitsanulok, Thailand. Photo by Nikolay A. Poyarkov. C. Adult female C. interdigitalis from Tak Mal National Park, Phetchabun Province, Thailand. Photo from Creative Commons Attribution Share Alike. Photo by Evan S. H. Quah. D. Adult female C. cf. interdigitalis (NCSM 79472) from Ban Pha Liep, Houay Liep Stream, Xaignabouli Province, Laos. Photo by Bryan L. Stuart. E. Adult female C. ngati (VNUF R. 2020.12) from Pa Thom Cave, Pa Xa Lao Village, Pa Thom Commune, Dien Bien District, Dien Bien Province, Vietnam. Photo by Dzung T. Le. F. Adult female C. brevipalmatus from the type locality at Khao Luang National Park, Nakon Si Thammarat Provice, Thailand. Photo from Creative Commons Attribution Share Alike. G. Adult male C. cf. ruhkhadeva sp. nov. form Kaeng _ Krachan National Park, Petchaburi Province, Thailand. Photo from Creative Commons Attribution Share Alike.

Figure 10. Habitat of Cyrtodactylus rukhadeva sp. nov. at the type locality: Khao Laem Mountain, Suan Phueng District, Ratchaburi Province, Thailand. (A) Submontane forest on the slopes of Khao Laem Mountain. (B) A male of the new species hiding among the roots of a strangler fig (Ficus sp.). Photos by Parinya Pawangkhanant.