Cyrtodactylus raglai, Nguyen & Duong & Grismer & Poyarkov, 2021

Nguyen, Anh The, Duong, Tang Van, Grismer, L. Lee & Poyarkov, Nikolay A., 2021, A new granite cave-dwelling Bent-toed Gecko from Vietnam of the Cyrtodactylus irregularis group (Squamata; Gekkonidae) and a discussion on cave ecomorphology, Vertebrate Zoology 71, pp. 155-174 : 155

Cyrtodactylus raglai sp. nov.

Suggested Common Name: Raglai Bent-toed Gecko; Figures 6 , 7 , 9

Holotype.

Adult male, SIEZC 2.0244, collected from Song Giang River Valley (12.37079°N, 108.83643°E; at elevation 500 m a.s.l.), Khanh Trung Commune, Khanh Vinh District, Khanh Hoa Province, Vietnam, by Anh The Nguyen on 22 September 2020.

Paratypes.

Two adult females, SIEZC 2.0243 and ZMMU R16688 bearing the same data as the holotype except that the latter was collected on 16 August 2020.

Diagnosis.

Cyrtodactylus raglai sp. nov. can be separated from all other species of clade1 of the C. irregularis group by having 10 or 11 supralabials; nine or 10 infralabials; 44-47 paravertebral tubercles; 14 or 15 rows of longitudinally arranged tubercles; 36-39 ventrals; 8-10 expanded subdigital lamellae, 12 or 13 unexpanded subdigital lamellae, and 21-22 total subdigital lamellae on the fourth toe; 18 or 19 enlarged femorals; 12 enlarged precloacals; four rows of enlarged post-precloacals; three postcloacal tubercles in males; five precloacal pores in the male; no pitted precloacal scales in females; enlarged femorals and enlarged precloacals not continuous; proximal femorals less than one-half size of distal femorals; enlarged subcaudals; maximum SVL 111.7 mm; small, irregularly shaped dark blotches on top of head; and four irregularly shaped body bands edged with white tubercles wider than the interspaces (Tables 5 , 6 ).

Description of holotype

(Figs 6 , 7 ). Adult male SVL 95.0 mm; head moderate in length (HL/SVL 0.28) and width (HW/HL 0.66), flattened (HD/HL 0.38), distinct from neck, triangular in dorsal profile; lores concave anteriorly, weakly inflated posteriorly; prefrontal region slightly concave; canthus rostralis rounded; snout elongate (ES/HL 0.42), flat, rounded in dorsal profile; eye large (ED/HL 0.25); ear opening narrow, 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; 10(R,L) rectangular supralabials extending to below midpoint of eye, second supralabial slightly larger than first; 9(R,L) infralabials tapering smoothly to slightly past the termination of enlarged supralabials; scales of rostrum and lores flat, same size as granular scales on top of head and occiput; scales of occiput intermixed with small, distinct, tubercles; superciliaries elongate, 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 fourth infralabial; gular and throat scales small, granular, grading posteriorly into slightly larger, flatter, smooth, imbricate, pectoral and ventral scales.

Body relatively short (AG/SVL 0.43) with well-defined ventrolateral folds; dorsal scales small, granular, interspersed with small, rounded, semi-regularly arranged, smooth tubercles; tubercles extend from occiput onto base of tail forming transverse rows; approximately 14 longitudinal rows of tubercles at midbody; approximately 46 paravertebral tubercles; 36 flat, imbricate, ventral scales much larger than dorsal scales; five large, pore-bearing, precloacal scales; no deep precloacal groove or depression; and four rows of large post-precloacal scales on midline.

Forelimbs thin, relatively long (FL/SVL 0.16); lacking tubercles, granular scales slightly larger than those on body; palmar scales rounded, slightly raised; digits well-developed, inflected at basal interphalangeal joints; digits slightly narrower distal to inflections; subdigital lamellae transversely expanded, those proximal to joint inflections wider than those distal to inflection; claws well-developed, sheathed by a dorsal and ventral scale; hind limbs thin, more robust than forelimbs, long (TBL/SVL=0.20), covered dorsally by granular scales interspersed with slightly larger, weakly keeled tubercles and anteriorly by flat, slightly larger scales; ventral scales of thigh flat, imbricate, larger than dorsals; subtibial scales large, flat, imbricate; one row of 10(R)9(L) enlarged femoral scales terminating distally before knee, not continuous with enlarged precloacal scales; proximal femoral scales 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, slightly narrower distal to inflections; subdigital lamellae transversely expanded, those proximal to joint inflections wider than those distal to inflection, 10(R,L) transversely expanded subdigital lamellae on fourth toe proximal to joint inflection that extends onto the sole; 12(R,L) narrower lamellae distal to inflection; 22 total subdigital lamellae; and claws well-developed, sheathed by a dorsal and ventral scale at base.

Tail long (TL/SVL 1.25), original, 119 mm in length, 9.0 mm in width at base, tapering to a point; dorsal caudals small, generally square; median row of subcaudals transversely expanded, significantly larger than dorsal caudals, not extending up onto lateral side of tail; transverse rows of 2-4 keeled tubercles on anterior one-half of tail, paravertebral tubercles largest; tubercle rows separated by 7-9 rows of dorsal caudals; base of tail bearing small hemipenal swellings with three large postcloacal tubercles on either side; and postcloacal scales flat, imbricate.

Coloration in life (Figs 6 , 7 ). Ground color of top of head, limbs, and dorsum gray; top of head heavily mottled with irregularly shaped, small, dark-brown blotches, light-colored reticulate pattern absent; dark-brown, nuchal loop extends from posterior margin of one orbit to posterior margin of other orbit, anterior and posterior margins on nape jagged, no anterior azygous notch; no dark banding on nape; four dark-brown, irregularly shaped, dorsal body bands reaching ventrolateral folds extending from shoulders to pelvis, wider than light-colored interspaces, bearing lightened vertebral areas, edged in light-colored tubercles; interspaces bearing dark markings; limbs dark-brown with irregularly shaped, light-colored markings; eight, wide, dark-brown caudal bands much wider than seven; light-colored caudal bands do not encircle tail and have darkened centers; iris gold bearing thin, black reticulations; edges of pupils orange; venter beige with faint, dark mottling on lateral edges of belly, undersides of limbs; and subcaudal region dark-brown.

Variation

(Fig. 7 ). The paratypes resemble the holotype very closely in all aspects of coloration and pattern. Specimens ZMMU R16688 and SIEZC 2.0243 have eight and nine light-colored caudal bands, respectively, as opposed to seven in the holotype and SIEZC 2.0243 has 10 dark-brown caudal bands as opposed to eight in the holotype. Meristic and mensural variation is presented in Table 6 .

Distribution

(Fig. 1 ). Cyrtodactylus raglai sp. nov. is known only from the type locality in the Song Giang River valley, Khanh Trung Commune, Khanh Vinh District, Khanh Hoa Province, Vietnam.

Etymology.

The new species name " Cyrtodactylus raglai " is given in a reference to the Raglai people, an ethnic group living in the forested mountain areas of Khanh Hoa Province of Vietnam, including the Song Giang River Valley where the new species was found. In Raglai language, the self-designating word " Cyrtodactylus raglai " also means “forest”, stressing the importance of the tropical forest ecosystem for this people. To reflect this polysemy, the new species name is given as a noun in apposition and hence is invariable.

Comparisons.

Within the Cyrtodactylus irregularis group, C. raglai sp. nov. is most closely related to C. kingsadai , C. cryptus , and an undescribed species from Ba Na with which it forms a monophyletic group. It differs from both the described species in having a far greater maximum SVL (111.7 mm vs. 90.8-94 mm collectively) and fewer precloacal pores in the single male specimen (five vs. 7-11, collectively). It differs further from its sister species C. kingsadai in having significantly fewer supralabials (10 or 11 vs. 10-14, collectively), longitudinal rows of tubercles (14 or 15 vs. 14-23, collectively), and ventral scales (36-39 vs. 39-46, collectively), and a significantly longer head (adjusted head length 3.29-3.34 vs. 3.21-3.29, collectively) (Table 2 ; Figs 4 , 5 ). It differs further from C. cryptus by having significantly more supralabials, significantly fewer longitudinal rows of tubercles, ventral scales, enlarged subcaudals, a significantly longer head, longer snout, larger eye, and a significantly narrower head (Table 2 : Figs 4 , 5 ). From the other nominal species in clade 1, C. raglai sp. nov. differs having a greater maximum SVL (111.7 mm vs. 79.8-104.1 mm collectively), fewer ventral scales (36-39 vs. 39-57 collectively), fewer precloacal pores in the single male specimen (five vs. 6-11 collectively), no precloacal pits in females, and enlarged subcaudals (also lacking in C. pseudoquadrivirgatus and C. taynguyenensis ) (Table 5 ).

Natural history.

Cyrtodactylus raglai sp. nov. was recorded in the forested valley of Song Giang River in the northwestern part of Khanh Hoa Province (Fig. 1 ), in the vicinity of the Song Giang Hydropower Station. The surrounding mountains form the northeastern slopes of Langbian Plateau and are covered with polydominant montane evergreen tropical forest and are dissected by a rich network of small streams and rivulets that feed into the Song Giang River (Fig. 8A ). Scattered outcroppings of large granite boulders (ca. 3-5 m in height, 6-8 m in width) occur throughout the river valley and many of these have small permanent streams running through and beneath them. Here, soil erosion has formed small narrow caves among the boulders varying from 3-5 m in depth (Fig. 8B, C ) and C. raglai sp. nov. was only observed inside such caves or within crevices between the boulders. Lizards were elusive and difficult to find and only four specimens were recorded during three excursions to the area, and all were restricted only to specific outcroppings. Lizards were active from 19:00 h to 21:00 h, and were usually observed while foraging on the vertical surfaces of the boulders (Fig. 8C ) or hiding within the crevices. The two other species of Cyrtodactylus recorded in sympatry with the new species in the surrounding habitat were C. yangbayensis Ngo & Chan and Cyrtodactylus sp., both members of the Cyrtodactylus irregularis group. Both these species were quite numerous throughout the forested habitats of the Song Giang River Valley but occupied different microhabitats than that of C. raglai sp. nov. This type of habitat partitioning was also observed between the granite cave ecomorph C. hontreensis and habitat generalist C. condorensis on Hon Tre Island, Kien Giang Province, and between the granite cave ecomorph C. eisenmanae and C. condorensis on Hon Son Island, Kien Giang Province. In both cases, these species pairs were sympatric but never observed to be syntopic. A similar situation may exist on Ba Den Mountain, Tay Ninh Province among the cave ecomorphs C. bandeennsis and C. nigriocularis and the granite forest species C. thuongae that is not restricted to the caves ( Phung et al 2014). Other Gekko gecko species recorded in the Song Giang River Valley were Gekko gecko (Linnaeus) and Gekko grossmanni Günther.

Figures

Figure 1. Distribution of the species of the Cyrtodactylus irregularis group. Dot in the center of an icon indicates the type locality of a species. The small inset map shows Vietnam and the location of the area of studies detailed in a larger map (red rectangle). For details on species localities see Pauwels et al. (2018); Neang et al. (2020); and Ostrowski et al. (2020).

Figure 4. A. PCA of the Cyrtodactylus raglai sp. nov, C. cryptus, and C. kingsdai based on meristic characters. B. DAPC of same. C. Histograms of the factor loadings of the characters contributing the most to the variation along PC 1 and PC 2. D. Boxplot comparisons of meristic characters. Light-blue circles are means and black horizontal bars are medians. Species pairs above the plots are those that differ significantly (p <0.05) from each other based on the ANOVAs and TukeyHSDs.

Figure 5. A. PCA of the Cyrtodactylus raglai sp. nov, C. cryptus, and C. kingsdai based on mensural characters. B. DAPC of same. C. Histograms of the factor loadings of the characters contributing the most to the variation along PC 1 and PC 2. D. Boxplot comparisons of meristic characters. Light-blue circles are means and black horizontal bars are medians. Species pairs above the plots are those that differ significantly (p <0.05) from each other based on the ANOVAs and TukeyHSDs. Photographs by Anh The Nguyen.

Figure 6. Adult male holotype of Cyrtodactylus raglai sp. nov. (SIEZC 2.0244). A. Dorsal view. B. Ventral view of thighs and precloacal region. C. Right lateral view of head. D. Ventral view of gular region. E. Ventral view of left foot. F. Ventral view of left hand. Photographs by Anh The Nguyen.

Figure 7. Type series of Cyrtodactylus raglai sp. nov. A. Adult male holotype SIEZC 2.0244. B. Adult female paratype SIEZC 2.0243. C. Adult female paratype ZMMU R 16688. Photographs by Anh The Nguyen.

Figure 8. Habitat (A) and granite cave microhabitat (B and C) of Cyrtodactylus raglai sp. nov. at the type locality. Photographs by Anh The Nguyen.

Figure 9. General morphology of the six species of cave ecomorphs in the genus Cyrtodactylus from Vietnam. A. C. raglai sp. nov. from the Song Giang River Valley, Khanh Hoa Province. Photograph by Anh The Nguyen. B. C. hontreensis from Hon Tre Island, Kien Giang Province. Photograph by L. Lee Grismer. C. C. grismeri from Tuc Dup Hill, An Giang Province. Photograph by L. Lee Grismer. D. C. badenensis from Ba Den Mountain, Tay Ninh Province. Photograph by Nikolay A. Poyarkov. E. C. nigriocularis from Ba Den Mountain, Tay Ninh Province. Photograph by Nikolay A. Poyarkov. F. C. eisenmanae from Hon Son Island, Kien Giang Province. Photograph by Ngo Van Tri.