Gekko khunkhamensis, Sitthivong & Lo & Nguyen & Ngo & Khotpathoom & Le & Ziegler & Luu, 2021

Sitthivong, Saly, Lo, Oanh Van, Nguyen, Truong Quang, Ngo, Hanh Thi, Khotpathoom, Thananh, Le, Minh Duc, Ziegler, Thomas & Luu, Vinh Quang, 2021, A new species of the Gekko japonicus group (Squamata: Gekkonidae) from Khammouane Province, central Laos, Zootaxa 5082 (6), pp. 553-571 : 556-562

Gekko khunkhamensis sp. nov.

( Figs. 2–4 )

Holotype. VNUF R.2021.23 (Field no. SL. KM.23), adult male, (18°11’ N, 104°30’ E, at an elevation of 172 m a.s.l.), Nahin Village , Khunkham District, Khammouane Province, central Laos, collected by S. Sitthivong and Lo O. V. on 29 October 2019.

Paratypes. NUOL R.2021.22 (Field no. SL. KM.22), adult female ; VNUF R.2021.02 (Field no. SL. KM.02), adult female, the same data as the holotype .

Diagnosis. Gekko khunkhamensis sp. nov. is a member of the Gekko (Japonigekko) japonicus group and differs from all congeners by a combination of the following characters: a medium-sized gecko species (SVL 69.7–75.2 mm); nares in contact with rostral; internasals absent; postmentals enlarged; interorbital scales between anterior corners of the eyes 31 or 32; dorsal tubercles absent; ventrals between mental and cloacal slit 181–185; midbody scales 127–138; ventral scales 42–45; subdigital lamellae on first toe 13 or 14, on fourth toe 14 or 15; tubercles on upper surface of fore and hind limbs absent; precloacal pores absent in the male and females; postcloacal tubercles two; tubercles absent on dorsal surface of tail base; subcaudals distinctly enlarged; dorsal surface of body with five dark grey bands, which become irregular posteriorly.

Description of holotype. An adult male with a total length of 158.1 mm (SVL 69.7 mm, TaL 88.4 mm); body slender, elongate (TrunkL/SVL ratio 0.46); head longer than wide (HW/HL ratio 0.75); rostral quadrangular, nearly twice wider than high (RH/RW ratio 0.50) and wider than mental (MW/RW ratio 0.67), in contact with first supralabial and supranasal on each side; nostrils round, in contact with rostral, first supralabial, supranasal, and two enlarged nasals posteriorly; posterior nasal region concave; internasal absent; preorbitals 18/18, preorbital region deeply concave; interorbitals 31; eye large (OD/HL ratio 0.23), pupil vertical; ear opening oval, oblique, smaller than eye (EarL/OD ratio 0.53); mental triangular, wider than long (ML/MW ratio 0.81); enlarged postmentals two, hexagonal, twice longer than wide, and longer than length of mental, touching mental, first infralabial on both sides and seven gular scales posteriorly, outer gular scales larger than inner scales; supralabials 10/10; infralabials 9/9; dorsal scales on body smooth, round or oval, granular, juxtaposed; lateral fold distinct; ventrals distinctly larger than dorsal scales, smooth, imbricate, and largest in the middle of belly; ventrals at midbody 42; scales around midbody 127; ventrals in a row between mental and cloacal slit 185; scales on dorsal surface of forelimbs slightly enlarged; tubercles on dorsal surface of limbs absent; scales on anterior and ventral parts of femur larger than those on posterior and dorsal parts; enlarged femoral scales absent; fingers and toes basally webbed; subdigital lamellae under first fingers 13/13, under fourth fingers 15/15, under first toes 13/13, under fourth toes 15/15; precloacal pores absent; postcloacal tubercles 2/2; base of tail thickened, without tubercles on dorsal surface; subcaudals enlarged, smooth, imbricate.

Coloration in life. Dorsal head dark grey with grey blotches; labials grey with light bars; neck with a grey bar; dorsal surface of body grey with five dark grey bands, which become irregular posteriorly; dorsal surface of fore and hind limbs grey with dark blotches; ventral surface of head, belly, and limbs cream with black spots; upper tail with eight grey transverse bands, more distinct posteriorly; underside of tail grey.

Sexual dimorphism and variation. Compared to the male holotype, the two female paratypes have a larger size ( SVL 71.6–75.2 mm versus 69.7 mm in the male) and more scale rows at midbody (136–138 versus 127 in the male holotype). The dorsal pattern of the paratype ( VNUF R.2021.02) is somewhat irregurlarly banded. Measurements and scalation of the female paratypes are shown in Table 2 .

Comparisons. Based on examination of specimens and data obtained from the literature ( Boulenger 1907; Ota et al. 1995; Rösler et al. 2005, 2010, 2011; Yang et al. 2012, Nguyen et al. 2013; Luu et al. 2014, 2015; Ngo et al. 2015; Yang 2015; Luu et al. 2017) we compared the new species from Laos with the remaining members of the Gekko japonicus group ( rösler et al. 2011; Luu et al. 2015, 2017) in Table 3 . Below we compared the new species with the closely related species of the G. japonicus group as follows:

Gekko khunkhamensis sp. nov. is morphologically most similar to G. tawaensis Okada, 1956 . However, the new species can be distinguished from G. tawaensis by having fewer supralabials and infralabials (9 or 10 and 9 or 10 versus 15 and 13, respectively), internasals absent (versus present), postmentals enlarged (versus not enlarged), more subdigital lamellae under first and fourth toes (13 or 14 and 14 or 15 versus 10 and 12, respectively), more postcloacal tubercles (2 versus 1), and marking on upper head present (versus absent).

Gekko khunkhamensis sp. nov. does not have dorsal tubercles and thus differs from the following species which have tubercles on the back: G. adleri Nguyen, Wang, Yang, Lehmann, Le, Ziegler & Bonkowski, 2013 , G. auriverrucosus Zhou & Liu in Zhou et al., 1982, G. canhi Rösler, Nguyen, Doan, Ho, Nguyen & Ziegler, 2010 , G. chinensis Gray, 1842 , G. japonicus ( Schlegel, 1836) , G. hokouensis Pope, 1928 , G. kwangsiensis Yang, 2015 , G. liboensis Zhou & Li in Zhou et al., 1982, G. palmatus Boulenger, 1907 , G. scabridus Liu & Zhou in Zhou et al., 1982, G. shibatai Toda, Sengoku, Hikida & Ota, 2008 , G. similignum Smith, 1923 , G. swinhonis Günther, 1864 , G. vertebralis Toda, Sengoku, Hikida & Ota, 2008 , and G. wenxianensis Zhou & Wang, 2008 .

Distribution. Gekko khunkhamensis sp. nov. is currently known only from the type locality in Khunkham District, Khammouane Province, central Laos ( Fig. 5 ).

Etymology. The specific epithet “ khunkhamensis ” refers to the type locality of the new species, Khunkham District of Khammouane Province. We suggest the following common names: Khunkham Gecko (English, German), Kap Ke Khunkham (Laotian) and Gecko de Kunkham (French).

Natural history. Specimens of the new species were collected between 19:10 and 20:30, on karst cliffs near the entrance of a cave, from 0.5 to 2.0 m above the ground, at elevations between 172 and 320 m a.s.l. ( Fig. 6 ). The surrounding habitat was disturbed secondary forest of small wood trees and shrubs on the karst cliff. The humidity was approximately 60–70% and the air temperature ranged from 22–26 oC.

Figures

FIGURE 2. A) Dorsal view of the male holotype (VNUF R.2021.23); B) dorsolateral view of the female paratype VNUF R.2021.02); C) dorsolateral view of the female paratype (NUOL R.2021.22) of Gekko khunkhamensis sp. nov.

FIGURE 3. Cloacal region of the male holotype (VNUF R.2021.23) of Gekko khunkhamensis sp. nov.

FIGURE 4. Dorsal (A) and ventral (B) views of type series of Gekko khunkhamensis sp. nov. from the top to the bottom: the male holotype (VNUF R.2021.23); female paratype (VNUF R.2021.02); and female paratype (NUOL R.2021.22).

FIGURE 5. Map showing the type locality (red circle, upper left) of the new species in Khunkham District, Khammouane Province, central Laos, together with known localities of other Gekko (Japonigekko) japonicus group congeners.

FIGURE 6. Habitat of Gekko khunkhamensis sp. nov.