Gekko phuyenensis, Nguyen & Nguyen & Orlov & Murphy & Nguyen, 2021

Nguyen, Vu Dang Hoang, Nguyen, Luan Thanh, Orlov, Nikolai L., Murphy, Robert W. & Nguyen, Sang Ngoc, 2021, Gekko phuyenensis sp. nov. (Squamata: Gekkonidae), a new species from southern Vietnam, Zootaxa 4966 (2), pp. 175-186 : 179-183

Gekko phuyenensis sp. nov.

English: Phu Yen Marbled Gecko

Vietnamese: Tắc kè phú yên

Figs. 2 , 3 .

Holotype. ITBCZ 6653, adult male ( Figs. 2 , 3A ), Ninh Dong Commune, Tuy An District, Phu Yen Province, Vietnam, at an elevation of 5 m above sea level (13˚21’N, 109˚17’E), collected by V.D.H. Nguyen on 16 July 2018.

Paratypes. ITBCZ 6654 and ITBCZ 6656 (adult males), and ITBCZ 6655 (adult female, Fig. 3B ), the same data as the holotype.

Diagnosis. Gekko phuyenensis sp. nov. is distinguished from all of its congeners by a combination of the following morphological characters: medium size in adults (SVL up to 92.8 mm; nares in contact with rostral; nasals 3; internasal 1; interorbitals 35 or 36; ventrals 30–32; dorsal tubercle rows 9 or 10; precloacal pores (in males) 12 or 13, precloacal pits (in female) 13; subdigital lamellae under first finger 18–21, fourth finger 19 or 20, first toe 18–20, and fourth toe 21–23; subcaudals median enlarged; no webbing between toes, and absence of tubercles on hind limbs.

Description of holotype. Adult male. Size moderate, SVL 91.8 mm, tail original, TaL 104.5 mm; head relatively long (HL/SVL 0.29), depressed (HH/HL 0.40), distinct from neck; snout elongate (SE/HL 0.43), longer than eye diameter (ED/SE 0.46); scales on dorsal head and snout small, granular, and homogeneous; interorbitals 35; nares closer to snout-tip than to eye (NE/SE 0.78), bordered by rostral, nasorostral, supranasal, postnasal, and first supralabial; internasal 1; eyes medium in size (ED/HH 0.5), pupil vertical, superciliaries smooth, 8 ciliary spines; ear opening small (EarD/HL 0.15) and obliquely oval; eye to ear distance larger than eye diameter (EE/ED 1.48); supralabials 12 and infralabials 10, followed by small scales extending to jaw; rostral wider than mental; gulars 4; flat granules dominantly cover gular region.

Body elongate (AG/SVL 0.48) with weak ventrolateral folds; scales on back small, round, granular, and intermixed with 10 enlarged and smooth dorsal tubercle rows at midbody; tubercles absent on forelimbs, hindlimbs, throat, and ventolateral folds; dorsal tubercles surround by 9 small granule scales; ventrals smooth and larger than dorsal scales; 32 scale rows across belly between midbody ventolateral folds; scales along underside of body from mental to front of cloacal slit 155; precloacal pores 12, arranged in two angular series interrupted by a poreless scale; 9 enlarged scale rows between pores and cloacal slit ( Fig. 3A ).

Limbs relatively long (ForeaL/SVL 0.14 and CrusL/SVL 0.18); scales on limbs homogeneously round and granular, without tubercles; fingers and toes compressed and without webbing between digits; claw absent on inner fingers and toes ( Fig. 2C–D ); subdigital lamellae under first finger 21, fourth finger 20, first toe 18, and fourth toe 22.

Original tail longer than snout-vent length (TaL/SVL 1.14), thicker at base; scales on dorsum of tail small, round, and granular; 99 median enlarged subcaudals; tail base with tubercles on dorsal surface and 2 enlarged smooth postcloacal tubercles on each ventrolateral side.

In everted condition, hemipenis smooth and distinctly bifurcated near tip forming 2 symmetric lobes; on asulcal side, proximal part smooth while tiny calyces occur from middle of organ to lobes ( Fig. 2E ); on sulcal side, sulcus lips prominent and smooth while lobes bear distinct folds ( Fig. 2F ).

Coloration. In life, dorsal background dark green to dark brown. Dorsum with darkish blotches and smaller whitish blotches alternately. Blotches enlarged on vertebrate and symmetrically but smaller on flanks. Ventral side yellowish to white without pattern. In preservative, the color became faint, but pattern is constant ( Fig. 2 A&B ).

Variation. Paratypes agree with holotype in color pattern both in life and in preservation. Maximum SVL is 92.8 mm in paratype ITBCZ 6654 (male). Series of precloacal pores of two males, including the holotype (ITBCZ 6653) and paratype (ITBCZ 6654), are interrupted by a pore-less scale, while they are continuous in paratype (ITBCZ 5566). Variation in size and scalation of the type series are shown in Table 3 .

Sexual dimorphism. The adult female slightly smaller than adult males (SVL 90.2 mm versus 91.8–92.8 mm

[n = 3]). The female with 13 precloacal pits ( Fig. 3B ) while males bear distinct pores ( Fig. 3 ).

Etymology. The specific epithet phuyenensis is a toponym derived from the Phu Yen Province, southern Vietnam where the new gecko was discovered.

Comparisons. Among members of the Gekko petricolus group, Gekko phuyenensis sp. nov. can be distinguished from G. badenii by having fewer dorsal tubercles rows (9 or 10 versus 12–17), more subdigital lamellae beneath first and fourth toes (18–20 versus 12–14 and 21–23 versus 15–20, respectively), absence (versus presence) of back banded, and presence (versus absence) of precloacal pits in the female; from G. boehmei by having fewer dorsal tubercles rows (9 or 10 versus 12–15), absence (versus weakly developed) of toe webbing, absence (versus presence) of tubercles on hind limbs, presence (versus absence) of precloacal pits in the female, and higher number of subdigital lamellae under first and fourth fingers, first and fourth toes (18–21 versus 12 or13, 19 or 20 versus 15 or 16, 18–20 versus 14–16, and 21–23 versus 17 or 18, respectively); from G. canaensis by having more subdigital lamellae under first and fourth fingers, first and fourth toes (18–21 versus 14–17, 19–20 versus 16–18, 18–20 versus 14–16, and 21–23 versus 17–19, respectively) and more precloacal pits in the female (13 versus 0–3); from G. grossmanni by having more subdigital lamellae under fourth fingers, first and fourth toe (19 or 20 versus 17 or 18, 18–20 versus 15 or 16, and 21–23 versus 19 or 20, respectively) and more precloacal pits in the female (13 versus 0–2); from G. cf. grossmanni in Binh Hung, Khanh Hoa Province, Vietnam (n=1) by having fewer dorsal tubercle rows (9–10 versus 12), presence (versus absence) of internasal, and more subdigital lamellae under fourth fingers, first and fourth toes (19 or 20 versus 17, 18–20 versus 16, and 21–23 versus 16, respectively); from G. cf. grossmanni in Hon Ba, Khanh Hoa Province, Vietnam (n=3) by fewer dorsal tubercle rows (9 or 10 versus 12 or 13), presence (versus absence) of internasal, and more subdigital lamellae under first and fourth fingers, first and fourth toes (18–21 versus 17, 19 or 20 versus 17 or 18, 18–20 versus 17, and 21–23 versus 18 or 19, respectively); from G. cf. grossmanni in Ninh Hoa, Khanh Hoa Province, Vietnam (n=3) by having a larger SVL (90.2–92.8 versus 70.2–76.4 mm), fewer interorbitals (35 or 36 versus 42–44), more granule surrounding dorsal tubercle (9 versus 8), more subdigital lamellae under fourth fingers, first and fourth toes (19 or 20 versus 15, 18–20 versus 14–16, and 21–23 versus 16–18, respectively); from G. flavimaritus by having a larger SVL (90.2–92.8 versus 67.5–84.5 mm), fewer dorsal tubercles rows (9 or 10 versus 12–16), more subdigital lamellae under first and fourth toes (18–20 versus 10–15, and 21–23 versus 15–18, respectively), absence (versus weakly developed) of toe webbing, more precloacal pores in males (12 or 13 versus 7 or 8) and presence (versus absence) of precloacal pits in the female; from G. lauhachindai by having fewer dorsal tubercles rows (9 or 10 versus 14), absence (versus presence) of back banded, presence (versus absence) of precloacal pits in the female, and more subdigital lamellae under first and fourth toes (18–20 versus 13 and 21–23 versus 13–15, respectively); from G. petricolus by having fewer dorsal tubercles rows (9 or 10 versus 15–18), more subdigital lamellae under first and fourth toes (18–20 versus 12–14 and 21–23 versus 16–18, respectively), and absence (versus presence) of tubercles on hindlimbs; from G. russelltraini by having fewer dorsal tubercles rows (9 or 10 versus 12–16), more subdigital lamellae under first and fourth fingers, first and fourth toes (18–21 versus 12–16, 19 or 20 versus 14–17, 18–20 versus 15 or 16, and 21–23 versus 17–19, respectively), more precloacal pores in males (12 or 13 versus 8–11) and presence (versus absence) of precloacal pits in the female; and from G. takouensis by having fewer dorsal tubercles rows (9 or 10 versus 14–17), more subdigital lamellae under first and fourth fingers, first and fourth toes (18–21 versus 15, 19 or 20 versus 17 or 18, 18–20 versus 14–16, and 21–23 versus 18–20, respectively), and presence (versus absence) of precloacal pits in the female.

Distribution. Gekko phuyenensis sp. nov. is currently known from the type locality in Ninh Dong Commune, Tuy An District, Phu Yen Province, Vietnam ( Fig. 1 ).

Natural history. All specimens were collected during the daytime, on rocky outcrop walls close to the sea ( Fig. 4 ). Surrounding habitat was shrubs, liana, interspersed by outcrop granite.At the collected sites, the temperature was 28.1–31.4 oC, relative humidity was 62.3–67.9%.

Figures

FIGURE 1. Bayesian inference (BI) tree for Gekko in southern Vietnam (left) and their sampling locations (right). Site numbers on the map and after species names refer to Table 1. Stars indicate type localities; nodal support values are BPP/UFB; scale bar is 0.1 substitutions per site; and a hyphen represents an un-supported node.

FIGURE 2. Holotype of Gekko phuyenensis sp. nov., ITBCZ 6653.A, dorsal view; B, ventral view; C & D, subdigital lamellae under fingers and toes, respectively; E & F, asulcal and sulcal views, respectively of everted right hemipenis.

FIGURE 3. Precloacal pores in the male holotype (A, ITBCZ 6653) and the female paratype (B, ITBCZ 6655) of Gekko phuyenensis sp. nov.

FIGURE 4. Habitat of Gekko phuyenensis sp. nov. in Phu Yen Province, southern Vietnam.