Gekko russelltraini, Tri, Ngo Van, Bauer, Aaron M., Wood, Perry L. & Grismer, Jesse L., 2009

Tri, Ngo Van, Bauer, Aaron M., Wood, Perry L. & Grismer, Jesse L., 2009, A new species of Gekko Laurenti, 1768 (Squamata: Gekkonidae) from Dong Nai Province, Southeastern Vietnam, Zootaxa 2238, pp. 33-42 : 34-38

Gekko russelltraini sp. nov.

Plate 1.

Holotype. Zoological Collection of University of Natural Sciences in Hochiminh City ( UNS) UNS 0 293, adult male (Plate 1A); Southeastern Vietnam, Dong Nai Province, Xuan Loc district, Suoi Cat Commune, Chua Chan Mountain, approximately 100 m elevation (10°55.799’N, 107°21.766’E), collected by Ngo Van Tri, 28 December 2005.

Paratypes. UNS 0 280, subadult male, UNS 0 281, adult female; Southeastern Vietnam, Dong Nai Province, Xuan Loc district, Suoi Cat Commune, Chua Chan Mountain, (10°57.591’N 107°22.662’E), collected by Ngo Van Tri, 27 December 2005; UNS 0 292, adult female; same locality and collector as UNS 0 280, collected 28 December 2005; UNS 0294–0295, adult males; Southeastern Vietnam, Dong Nai Province, Xuan Loc district, Xuan Truong Commune, Chua Chan Mountain, approximately 304 m elevation (10°55.819’N 107°21.757’E), collected by Ngo Van Tri, 31 December 2005; UNS 0358, 0 360, adult females, UNS 0 359, subadult male; same locality and collector as UNS 0 294, 30 November 2007.

Etymology. The epithet russelltraini is a patronym honoring the former president (1978–1985) and chairman (1985–1994) of the World Wildlife Fund in the United States, Dr. Russell Train (born 1920), who has supported funding and fellowships for generations of biologists to participate in conservation programs around the world, and in Vietnam in particular. The name is masculine and formed in the genitive singular. We suggest the following common names: English — Russell Train’s Marble Gecko and Vietnamese — Thằn lằn đá Russell Train.

Diagnosis. A medium sized Gekko , SVL to at least 82.9 mm. Gekko russelltraini sp. nov. may be distinguished from its congeners by the following combination of characteristics: Dorsum with 12–16 longitudinal rows of very weakly enlarged, smooth dorsal tubercles (Plate 1B); 90–101 scale rows around at midbody; 28–30 scale rows across venter between ventrolateral folds. Precloacal pores in a continuous series of 8–11 in males (Plate 1C), femoral pores absent. Digit IV of pes with 17–18 lamellae. Dorsal pattern of five to seven white vertebral blotches between nape and sacrum and four to seven pairs of short, sometimes irregular, white bands on flanks between limb insertions.

Gekko russelltraini sp. nov. may be distinguished from G. subpalmatus Günther , G. melli Vo g t, G. athymus Brown & Alcala , G. scientiadventura , and G. tawaensis Okada by the presence of dorsal tubercles; from G. tawaensis Okada and G. vertebralis Toda et al. and G. s h i b a t a i Toda et al. by the presence of precloacal pores in males; from G. v i t t a t u s Houttuyn, G. porosus Taylor , G. gigante Brown & Alcala, G. k i k u c h i i Oshima, G. mindorensis Taylor , G. monarchus (Schlegel) , G. romblon Brown & Alcala , G. palawanensis Taylor , G. ernstkelleri Rösler et al. , and G. crombota Brown et al. by the lack of femoral pores in males; from G. g e c k o, G. smithii Gray , G. albofasciolatus Günther , G. siamensis Grossmann & Ulber , and Gekko nutaphandi Bauer et al. by its much smaller size (maximum 83 mm SVL versus 110 mm SVL and greater) and rostral participation in the nostril border, from G. verreauxi Tytler by much smaller size (83 versus 130 mm SVL) and smaller number of lamellae under digit IV of the pes (17–19 versus 21–22); from G. chinensis , G. palmatus , G. similignum Smith , and G. ulikovskii by its lower number of midbody scale rows (90–107 versus 118 or more); from G. japonicus , G. swinhonis Günther , G. auriverrucosus Zhou & Liu , G. scabridus, Liu & Zhou , G. liboensis, Zhou & Li , G. taibaiensis Song, and G. wenxianensis Zhou & Wang by a larger number of lamellae beneath digit IV of the pes (17–18 versus 9 or fewer); from G. hokouensis Pope and G. yakuensis Matsui & Okada by the presence of two (versus one) cloacal spur on each side of tail base; and from G. badenii by a lower number of precloacal pores (8–11 versus 14–18).

Gekko russelltraini is most similar to G. petricolus Taylor of Thailand and G. grossmanni Günther , a Vietnamese endemic known only from Khanh Hoa Province. The new species shares with both of these species a similar dorsal pattern with a yellowish background and series of whitish spots and very similar standard scalation counts. Together with G. badenii and G. ulikovskii , these three species constitute a putative clade within the genus ( Günther 1994). Based on the type series, G. russelltraini is considerably smaller than G. petricolus (maximum SVL 83 mm versus 98 mm) and slightly smaller than G. grossmanni (maximum SVL 90 mm). It further differs from G. grossmanni in a lower number of precloacal pores (8–11 versus 12–14). It differs from both species in having a light purplish-brown venter (versus yellowish to dirty white in G. petricolus and whitish to gray in G. grossmanni ) and in the details of dorsal pattern. Although all three species show variation in pattern, the mid-flank white markings in G. russelltraini are invariably elongated to form distinct vertical bars, either entire or broken (versus rounded, oval or rhomboidal spots in the other species) and the pale markings on the parietal table are typically fused to form a transverse bar (verses a series of small, discrete spots).

PLATE 1. Gekko russelltraini sp. nov. (A) Male holotype (UNS 0293) in life. (B) Dorsal scalation of holotype at midbody showing the rows of very small tubercular scales. (C) Ventral view of cloacal region and thighs of holotype illustrating the uninterrupted series of pore-bearing scales and the absence of enlarged femoral scales. (D) Female paratype (UNS 0358) and (E) Male paratype (UNS 0359) illustrating variation in dorsal color pattern.

Description. Based on holotype, UNS 0 293, adult male. SVL 71.3 mm. Head relatively long (HeadL/ SVL = 0.27) and wide (HeadW/HeadL = 0.70), somewhat depressed (HeadD/HeadL = 0.43); distinct from neck, snout taping, rounded at tip. Loreal and interorbital regions weakly inflated, frontonasal region strongly concave, snout elongate (SnEye/HeadL 0.45), pointed, longer than eye diameter (OrbD/SnEye = 0.58); scales on snout and forehead small, granular, homogeneous; scales on snout larger than those on occipital region except for scattered smooth tubercles (~ 2–3 times size of adjacent scales); 30 interorbital scale rows. Eye large (OrbD/HeadL = 0.26); pupil vertical with crenelated margins; superciliaries smooth, short, bearing several minute conical spines posteriorly. Ear opening obliquely oval, small (EarL/HeadL = 0.1); eye to ear distance longer than diameter of eye (EyeEar/OrbD = 1.28). Rostral quadrangular, much wider (2.6 mm) than high (1.2 mm), with a “Y”-shaped median groove. Enlarged supranasals in contact anteriorly, separated by a two small internasals in longitudinal series posteriorly, only anterior of these entirely between supranasals, posterior extending beyond supranasal border; rostral in contact with supralabial I and supranasals; nostrils round, each surrounded by supranasal, rostral, first supralabial and two enlarged postnasals; 3–4 rows of small scales separate orbit from supralabials. Mental triangular, wider (1.3 mm) than deep (1.0 mm); anterior pair postmentals elongated (2.3 mm long, 0.7 mm wide), each bordered anteromedially by mental, medially in broad contact with other postmental, bordered anterolaterally by first infralabial, laterally by second postmental, posteriorly by four enlarged chin scales; 13 (right) to 14 (left) supralabials, 13 sublabials on both sides; 17 interorbital scale rows.

Body slender, relatively short (TrunkL/SVL 0.43) with weak ventrolateral folds. Dorsal scales smooth, round, granular, juxtaposed; 101 scale rows around midbody, intermixed with enlarged, smooth tubercles (3– 4 times size of adjacent scales, smaller on flanks, and smallest in occipital region) extending from occipital region to tail base; tubercles in 16 rows at midbody. Ventral scales much larger than dorsals, smooth, relatively round, and imbricate, largest posteriorly; 28 scale rows across venter between ventrolateral folds; gular region with relatively homogeneous, smooth scales. Ten precloacal pores arranged in a weakly anguled series; scale rows immediately anterior and posterior of pore-bearing scales somewhat enlarged; no enlarged femoral scales. Scales of palms and soles smooth, flattened, round, subimbricate without enlarged tubercles; scales on venter of fore and hind limbs with smooth, flattened, subimbricate scales.

Limbs long and slender (ForeaL/SVL 0.13; CrusL/SVL 0.18). Digits moderately dilated, all bearing slightly curved claws except the first finger and toe; number of broad lamellae beneath each digit (14–15–17– 17–16 manus; 15–14–18–18–15 pes); one to two narrow lamellar rows at base of digits; interdigital webbing weakly developed. Length of digits (manus; measurement in mm in parentheses): IV(5.6)> II(4.9)> III(4.8)> V(4.7)> I(4.3); (pes): III(6.2)> IV(5.7)> II(5.5)> V(4.8)> I(4.7).

Original tail slender, tapering to tip; longer than snout vent length (TailL/SVL = 1.19). Tail base with two smooth cloacal spurs on each side. Tail segmented, each segment 11 dorsal scales rows and 4 transversely enlarged subcaudal scales in length; scales of tail dorsum heterogeneous — rectangular to pentagonal or hexagonal, juxtaposed. Tail venter of postpygal region with a single series of 78 transversely enlarged scales followed distally by a series of 10 pairs of scales under tail tip.

Coloration. In life body dorsum mottled golden mustard yellow on purplish-brown. More-or-less contiguous areas of solid purplish brown on nape and in paravertebral position. A series of six opalescent white markings along vertebral line from nape to sacrum, each somewhat longer than broad. Mid-flanks with series of white vertical bars (one on shoulder, four between axilla and groin) alternating with a series of small white spots near ventrolateral margin of flanks (four between axilla and groin) (Plate 1A). Head mottled like dorsum with a whitish cross bar across posterior portion of parietal table and roughly longitudinal grayishwhite markings on canthal ridges and nasal region. Smaller, scattered whitish markings on crown, temple, and near rictus. Purplish-brown collar on occiput extending forward through orbit to lateral surface of snout. Iris beige to coppery brown. Limbs mottled and marked with regularly arranged whitish bars or spots. Metapodial and phalangeal joints with whitish markings, alternating with purplish-brown mottled interspaces. Tail with white bars alternating with longer purplish-brown bars. Six white bars on original tail. Venter light purplish brown, darker under chest and groin.

In life the overall color darkens or lightens depending on the ambient conditions. In preservative the dorsum of the holotype and most other voucher specimens is lighter than in life and white markings have faded to cream, beige, or brown.

Variation. Variation in mensural and meristic features is summarized in Table 1 . The condition of the internasals differs in some paratypes: in UNS 0 358 the supranasals are in contact along their entire length, whereas in UNS 0 292 a single, relatively large, internasal separates the supranasals from one another, except at their junction with the rostral. Because this feature is variable even at a single locality we do not consider internasal presence or number to be diagnostically meaningful in this taxon. Color pattern is quite variable. White vertebral markings 6–7, pairs of white flank markings 4–6; white markings may be fused or fragmented and may be markedly asymmetrical (Plate 1D-E).

Natural history. All specimens were collected at night, between 20:00 and 21:45. The holotype and paratypes UNS 0280–UNS 0 281 and UNS 0 292 were collected on shrubs close to the entrance of a granitic cave on Chua Chan Mountain ( Figs. 1–2 ). UNS 0 281 and UNS 0 292 are gravid and contain two eggs visible through the skin of the venter.

Figures

FIGURE 1. Map showing the type locality (red triangle) of Gekko russelltraini sp. nov., Chua Chan Mountain, southeastern Vietnam.

FIGURE 2. Habitat of Gekko russelltraini sp. nov. on Chua Chan Mountain, Dong Nai Province, southern Vietnam.