A new species of the Gekko japonicus group (Squamata: Gekkonidae) from Khammouane Province, central Laos Author Sitthivong, Saly Faculty of Forest Resources and Environmental Management, Vietnam National University of Forestry, Xuan Mai, Chuong My, Hanoi, Vietnam. & Faculty of Forestry, National University of Laos, Dong Dok Campus, Vientiane, Lao PDR. Author Lo, Oanh Van Faculty of Forest Resources and Environmental Management, Vietnam National University of Forestry, Xuan Mai, Chuong My, Hanoi, Vietnam. & Center for Nature Conservation and Development, 5,56 / 119 Tu Lien Street, Tay Ho District, Ha Noi, Vietnam. Author Nguyen, Truong Quang 0000-0002-6601-0880 Institute of Ecology and Biological Resources, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Hanoi, Vietnam. nqt 2 @ yahoo. com; https: // orcid. org / 0000 - 0002 - 6601 - 0880 & Graduate University of Science and Technology, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Hanoi, Vietnam. nqt2@yahoo.com Author Ngo, Hanh Thi 0000-0002-5283-6243 Central Institute for Natural Resources and Environmental Studies, Vietnam National University, Hanoi, 19 Le Thanh Tong, Hanoi, Vietnam. & Faculty of Biology, University of Science, Vietnam National University, Hanoi, 334 Nguyen Trai Road, Hanoi, Vietnam. ngohanhhus @ gmail. com; https: // orcid. org / 0000 - 0002 - 5283 - 6243 ngohanhhus@gmail.com Author Khotpathoom, Thananh Faculty of Forestry, National University of Laos, Dong Dok Campus, Vientiane, Lao PDR. Author Le, Minh Duc 0000-0002-2953-2815 Central Institute for Natural Resources and Environmental Studies, Vietnam National University, Hanoi, 19 Le Thanh Tong, Hanoi, Vietnam. & Faculty of Environmental Sciences, University of Science, Vietnam National University, Hanoi, 334 Nguyen Trai Road, Hanoi, Vietnam. le. duc. minh @ hus. edu. vn; https: // orcid. org / 0000 - 0002 - 2953 - 2815 & Department of Herpetology, American Museum of Natural History, Central Park West at 79 Street, New York, New York 10024, USA. le.duc.minh@hus.edu.vn Author Ziegler, Thomas AG Zoologischer Garten Köln, Riehler Strasse 173, D- 50735 Cologne, Germany. & Institute of Zoology, University of Cologne, Zülpicher Strasse 47 b, D- 50674 Cologne, Germany. Author Luu, Vinh Quang Faculty of Forest Resources and Environmental Management, Vietnam National University of Forestry, Xuan Mai, Chuong My, Hanoi, Vietnam. text Zootaxa 2021 2021-12-22 5082 6 553 571 journal article 2874 10.11646/zootaxa.5082.6.3 ef339fe0-57ad-4f5f-bec5-bf32a579b2bc 1175-5326 5797638 F51AF3C5-8F41-4419-A972-8D33423DF2A7 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: TABLE 2. Measurements (in mm) and morphological characters of the type series of Gekko khunkhamensis sp. nov. (for abbreviations see materials and methods). (* = tail regenerated).

Character	VNUF R.2021.23 (Holotype)	NUOL R.2021.22 (Paratype)	VNUF R.2021.02 (Paratype)
Sex	adult male	adult female	adult female
SVL	69.7	75.2	71.6
TaL	88.4	69.7*	75.7*
TrunkL	32.1	33.5	33.2
HL	18.3	18.6	18.7
HW	13.8	14.2	13.9
HH	6.8	7.6	7.8
SE	7.1	7.5	7.6
EyeEar	4.4	4.9	5.1
ForeL	16.7	17.1	16.3
FemurL	11.8	12.2	12.8
CrusL	12.1	12.1	12.5
LD4A	5.1	5.7	5.2
LD4P	6.4	6.8	6.5
OD	4.3	4.3	4.6
EarL	2.3	2.4	2.4
RW	2.4	2.4	2.5
RH	1.2	1.3	1.3
MW	1.6	1.7	1.8
ML	1.3	1.3	1.5
CS	5/5	6/5	7/8
N	3/3	3/3	3/3
IN	0	0	0
SL	10/10	9/10	10/10
IL	9/9	9/9	10/10
IO	31	32	31
PO	18	18	19
PM	2	2	2
GP	7	7	7
DTR	0	0	0
GST	0	0	0
SLB	185	182	181
SR	127	136	138
V	42	44	45
LF1	13/13	14/14	13/13
LF4	15/15	15/15	15/14
LT1	13/13	14/14	13/13
LT4	15/15	15/15	15/14
FPl+FPr	0	0	0
PP	0	0	0
PAT	2/2	2/2	2/2

TABLE 3. Morphological comparisons among the species of the Gekko japonicus group (modified after Luu et al . 2017 , abbreviations defined in text, - = data unavailable).

Character	Gekko khunkhamensis sp. nov.	aaronbaueri	adleri	auriverrucosus	bonkowskii	canhi	chinensis	japonicus	hokouensis
Maximum SVL (mm)	75.2	80.0	75.3	69	69.2	99.2	72	74	70
SL (min–max)	9–10	13–14	10–15	9–11	12–14	14	10–14	9–13	10–14
IL (min–max)	9–10	10–11	9–13	9–11	10–11	10–12	9–13	8–13	8–11
Nostril touching rostral	1	1	1	0	1	1	1	1	1
N (min–max)	3	3	3	3	3	3	2–3	3	3
IN (min–max)	0	0–1	1	0–1	0	1	1	0–1	1
IO (min–max)	31–32	34–37	27–36	25–25	26–27	49–50	35–48	32–35	30–33
Postmentals	1	1	0	1	1	1	0	0
(enlarged = 1, not enlarged = 0)	1
DTR (min–max)	0	0	7–11	16–20	0	11–12	10	9–14	12–18
SLB (min–max)	181–185	-	168–190	-	154–169	168–170	156–167	169–188	153–174
SR (min–max)	127–138	98–104	123–144	-	117	205–227	118–140	130–144	119–130
V (min–max)	42–45	39–43	35–44	-	37–40	49–51	37–39	39–44	36–43
LT 1 (min–max)	13–14	14–17	11–14	6–8	11–13	13–16	8–10	10–12	8–11
LT 4 (min–max)	14–15	14–16	11–15	6–8	15	14–17	9–12	14–16	15–18
Toes webbed	1	-	1	0	1	0	1	0	0
Tubercles on fore-limbs (present = 1, absent = 0)	0	0	0	1	0	0	0	1	0
Tubercles on hind limbs (present = 1, absent = 0)	0	0	1	1	0	1	1	1	0
PP (in males, min–max)	0	3–4	17–21	8–11	6	5	17–27	6–9	5–9
PAT (min–max)	2	1–2	1	2–3	0–2	2–3	1	2–4	1
Tubercles on dorsal surface of tail (present = 1, absent = 0)	0	0	1	1	0	0	1	1	1
Subcaudals enlarged	1	1	1	1	1	1	1	1	1
Marking on upper head	1	1	1	0	0	0	0	0	0
Back flecked or blotched	1	1	0	0	1	1	1	0	1
Back banded	1	0	1	1	0	1	0	1	0
Tail banded	1	1	1	1	1	1	1	1	1

TABLE 3. (continued)

Character	kwangsiensis	liboensis	melli	nadenensis	palmatus	scabridus	scientiadventura	sengchanthavongi	shibatai
Maximum SVL (mm)	69.7	85	84.6	77.1	79.7	77	73	77.3	70.9
SL (min–max)	10–12	12	10–13	12–14	11–15	9–11	12–14	8–10	10–13
IL (min–max)	11–13	11	9–12	10–12	9–13	9–11	9–13	6–7	10–14
Nostril touching rostral	1	1	1	1	1	1	1	1	1
N (min–max)	3	3	3	3	3	3	3	3	3
I (min–max)	0–1	0–0	1–1	0–0	0–3	1–2	0–0	0–0	0–1
IO (min–max)	29–31	40–40	34–40	28–30	27–36	30–30	41–51	28–32	37–52
Postmentals (enlarged = 1, not enlarged = 0)	1	0	0	1	1	0	1	1	0
DTR (min–max)	9–11	10	0	0	4–12	17–21	0	0	5–14
SLB (min–max)	185–208	-	181–200	175–185	160–194	-	118–140	175–184	-
SR (min–max)	143–156	-	147–160	123–140	116–147	-	139–143	120–135	114–134
V (min–max)	41–45	-	43–49	38–40	36–47	-	38–48	35–43	-
LT 1 (min–max)	11–13	8	10–12	13–15	10–13	6–9	12–15	11–14	-
LT 4 (min–max)	13–18	9	11–14	14–16	10–16	7–9	14–17	13–17	9–16
Toes webbed	1	0	1	1	1	0	1	1	0
Tubercles on fore-limbs (present = 1, absent = 0)	0	0	0	0	0	1	0	0	0
Tubercles on hind limbs (present = 1, absent = 0)	0	0	0	0	0	1	0	0	0
PP (in males, min–max)	9–11	-	9–11	6(5+1) –6(3+3)	23–30	10–15	5–8	4(3+1) –5(3+2)	0–3
PAT (min–max)	1	1	1	1–2	1	1–3	2–3	2	1
Tubercles on dorsal surface of	1	-	0	1	1	0	0	1
tail (present = 1, absent = 0)	0
Subcaudals enlarged	1	-	1	1	1	1	1	1	1
Marking on upper head	0	0	1	1	0	0	1	0	0
Back flecked or blotched	0	0	0	1	1	1	1	1	1
Back banded	1	1	1	0	1	1	0	1	0
Tail banded	1	-	1	1	1	1	1	1	1

TABLE 3. (continued)

Character	similignum	subpalmatus	swinhonis	taibaiensis	tawaensis	thakhekensis	truongi	vertebralis	wenxianensis	yakuensis
Maximum SVL (mm)	58.9	72	66	69	71	79.2	95.9	69.2	59	72
SL (min–max)	12–14	8–12	7–12	9–10	15	12–14	13–15	10–15	12	12–13
IL (min–max)	11	7–12	7–11	8–10	13	10–11	11–13	10–15	11	9–13
Nostril touching rostral	1	1	1	1	1	1	1	1	1	1
N (min–max)	3	3	-	-	-	3	3–4	3	-	3
I (min–max)	1–1	1	-	-	2	0	0–1	0–2	1	1
IO (min–max)	46–48	32	23–24	28	-	22–26	45–48	35–50	-	-
Postmentals (enlarged = 1, not enlarged = 0)	0	0	0	-	0	1	1	0	-	0
DTR (min–max)	11	0	6–8	-	0	0	0	2–12	10	-
SLB (min–max)	-	-	-	-	-	165–174	160–172	-	-	-
SR (min–max)	144–153	-	-	-	-	110–116	131–143	112–139	-	-
V (min–max)	-	48	40	-	-	32–40	35–36	-	42–44	-
LT 1 (min–max)	11–13	7–9	6–9	6–7	10	11–13	11–13	-	6	10
LT 4 (min–max)	12–14	7–10	6–9	7–8	12	14–15	15–17	9–17	9	15
Toes webbed	1	1	0	-	0	1	0	0	0	0
Tubercles on fore-limbs (present = 1, absent = 0)	0	0	1	-	0	0	0	0	0	0
Tubercles on hind limbs (present = 1, absent = 0)	0	0	1	-	0	0	0	0	1	0
PP (in males, min–max)	17	5–11	7–9	4–6	0	1–5	10–11	0–1	6–8	6–8
PAT (min–max)	1	1	2–3	-	1	2	1	1–2	2–3	1
Tubercles on dorsal surface of tail (present = 1, absent = 0)	1	0	-	-	0	0	0	0	-	1
Subcaudals enlarged	1	1	1	-	1	1	1	1	-	1
Marking on upper side of head	0	0	0	0	0	0	0	0	0	0
Back flecked or blotched	1	1	1	1	1	1	1	1	1	1
Back banded	0	1	0	1	1	0	1	0	0	0
Tail banded	1	1	1	1	1	1	1	-	1	1

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. 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 .