Gekko truongi, Phung, Trung My & Ziegler, Thomas, 2011

Phung, Trung My & Ziegler, Thomas, 2011, Another new Gekko species (Squamata: Gekkonidae) from southern Vietnam, Zootaxa 3129, pp. 51-61 : 52-59

Gekko truongi sp. n.

Holotype: IEBR A.2011.1, adult male from Cuc Dong Cape, Ninh Hoa District, Khanh Hoa Province, South Vietnam, collected on 12 June 2011 by T. M. Phung ( Figs. 1 , 3 and 4 ).

Paratypes: ZFMK 92292, adult male, and IEBR A.2011.2, adult female, the same collection data as the holotype ( Fig. 2 ).

Diagnosis. Gekko truongi sp. n. can be distinguished from all congeners on the basis of the following combination of characters: medium size with maximum 95.9 mm SVL; supralabials 13–15; postmentals enlarged; interorbitals 45–58; dorsal tubercles absent; midbody scales 131–143; well developed lateral fold; scales between mental and cloacal slit 160–172; ventrals 35 or 36; subdigital lamellae below first toe 11–13, below fourth toe 15– 17; faint basal webbing between fingers and toes; precloacal pores in males 10 or 11; postcloacal tubercles in males 1/1; number of transverse dorsal scale rows in the middle of the third caudal whorl 11; subcaudals enlarged; dorsum grey with dark pattern and light blotches and lines; dark dorsal pattern shows interspersed yellow spots and consists of two w-shaped bands each at occiput and neck and four dark blotches on body; prominent light postocular stripe is absent; tail with dark bands.

Description of holotype. Rostral rectangular, wider than high (maximum rostral width 3.5 mm, maximum rostral height 1.6 mm, RW/RH 2.2) and wider than mental, medial rostral suture absent; supralabials 13/13; head without tubercles; nares in contact with rostral and first supralabial; nasals 3/3; nasorostrals square to roundish, about double the size of supranasals; postnasals smaller than nasorostrals; internasal rectangular, 1/3 as large as nasorostrals; snout with flat, elongate medial cavity, most prominent between eyes; lateral snout scales roundish to oval, somewhat convex, about twice the size of those in mid-rostral region; 61 scales between seventh supralabials; medial snout scales roundish to oval, convex; pupil vertical; 8/7 spinous ciliary scales posteriorly; ear opening vertically oblique, oval, about half as large as eye diameter; interorbitals 45, granular; nuchal region scales flat to granular, somewhat larger than medial interorbitals; temporal and nuchal regions without tubercles; mental triangular, wider than long (maximum mental width 2.4 mm, maximum mental length 2.2 mm, MW/ML 1.1), not distinctly larger than first infralabials; infralabials 11/12; postmentals two, elongated, three times longer than wide and longer than mental, anteriorly in contact with mental and first infralabials; medial suture between postmentals corresponds to the length of mental; gulars six, bordering postmentals; dorsals somewhat larger as medial snout scales, round, flat to slightly convex; middorsal tubercles are lacking; lateral fold weakly developed, without interspersed tubercles; midbody ventrals between lateral folds 36; midbody scales in 143 rows; ventral scales between mental and cloaca 160; upper and lower arm scales slightly enlarged dorsally, smooth; forelimbs without tubercles; femoral scales smooth, posteriorly becoming more granular; enlarged femorals absent (i.e., no sharp transition between anteriorly larger and posteriorly smaller scales); tibial scales dorsally flat to slightly granular, ventrally flat, smooth; limbs without tubercles; fingers and toes with faint basal webbing; claws sheathed by three scales, with the dorsal scale smallest; subdigital lamellae 13/13 under first finger, 14/16 under fourth finger, 12/12 under first toe, and 15/16 under fourth toe; precloacal pores 11, in a slightly curved series; enlarged scales posterior to precloacal pores in eight rows; postcloacal tubercles 1/1, conical; original tail somewhat thickened at base, with bands, and without tubercles; dorsal caudal scales as approximately twice the size of dorsal scales, round to squareish, flat, in regular transverse rows; third whorl in width of 11 dorsal scales; subcaudals flat, transversally enlarged; three subcaudals per whorl, with the last one more distinctly enlarged.

Color in preservative (70% ethanol). Dorsal ground colour grey; head with dark and light spots; dorsal head with two brownish regions, but which may be due to preservation (i.e., artefacts): one before eyes, on snout, and one behind eyes, before occiput; occiput with dark w-shaped band; also neck with dark, somewhat w-shaped band; three dark middorsal bands with light spots between axilla and groin, consisting each of two more or less discernible, medially fused dark blotches; another such dark dorsal band can be found between the hind limbs; in particular posteriorly, these dark dorsal body bands are framed with a more or less discernible thin light band, which is followed each by a distinct large, light blotch; flanks with indistinct dark blotches with light spots; in between these dark lateral blotches there are small light spots and vertical light lines; tail dorsally with nine broad dark bands containing light spots; light dorsal tail interspaces consist of light and grey parts; limbs with dark marbling with light spots and light dots and lines in between the dark elements; throat, body and underside of limbs except for grey undersides of hands and feet cream; underside of tail light grey to cream, in its last two thirds with black bands as the continuation of the dorsal banded pattern.

Color in life. For the colour pattern of the holotype in life see Fig. 1 . In contrast to the colour pattern in preservative, the light elements within the dark dorsal colour pattern are yellow to ochre in life. The yellow colouration is brightest in the flank region and at the level of the lateral fold. From figure 1 it is furthermore discernible that at least the males have a yellowish-cream underside at least of the belly in life.

Variation. For the variation of measurements, proportions and scalation characters of the male and female paratypes see Tables 1 –2. Both paratypes have at least parts of their tail regenerated: 42 mm of the tail of the male paratype, and 69 mm of the tail of the female paratype. In both paratypes, in particular in the female, the lateral folds are more conspicuous than in the holotype (which had a completely filled stomach, which might be the explanation for its hardly discernible lateral fold). With respect to potential sexual dimorphism, the adult female paratype is slightly smaller. The female paratype also lacks precloacal pores and postcloacal tubercles, and its dorsal colour pattern is somewhat paler compared to that of the adult male holotype and paratype. In the female paratype also only the tips of the underside of the fingers and toes are dark, not the whole undersides of hands and feet as is the case in the adult males. Hemipenes swellings in the holotype and the male paratype are conspicuous. The median dark mid-dorsal blotch is irregularly shaped in the female paratype (see Fig. 2 ).

Comparisons. Gekko truongi sp. n. differs from other Vietnamese Gekko by the following characters (after Darevsky & Orlov 1994; Günther 1994; Ota et al. 1995; Rösler et al. 2005; Ngo et al. 2009; Ngo & Gamble 2010; Nguyen, 2010; Nguyen et al. 2010; Rösler et al. 2010; Ngo & Gamble 2011; Rösler et al. 2011): from G. badenii Szczerbak & Nekrasova, 1994 (synonym G. u l i k o v s k i i Darevsky & Orlov, 1994; see Nguyen et al. 2009, Nguyen et al. 2010) by the absence of dorsal tubercle rows (versus 8–13 in G. badenii ), a greater number of interorbitals (45– 58 versus 30–46), and by different dorsal colour pattern; from G. canaensis Ngo & Gamble, 2011 by the absence of dorsal tubercle rows (versus 10–14 in G. canaensis ), by having fewer precloacal pores in males (10 or 11 versus 14–18), and by the number of postcloacal tubercles in males (1 versus 2 on each side in G. canaensis ); from G. canhi Rösler, Nguyen, Doan, Ho, Nguyen & Ziegler, 2010 , by the absence of dorsal tubercle rows (versus 10–13 in G. canhi ), a lower number of scales along underside of body from mental to cloaca (160–172 versus 205–229), having more precloacal pores in males (10 or 11 versus 5), and by the number of postcloacal tubercles in males (1 versus 2 or 3 on each side in G. canhi ); from G. gecko (Linnaeus, 1758) by a distinctly smaller body length (maximum 95.9 mm versus 161.0 mm), by the absence of dorsal tubercle rows (versus 11–13 in G. gecko ), having a lower count of precloacal pores (10 or 11 versus 12–16), more interorbitals (45–58 versus 17–29), and by a lower count of subdigital lamellae below the fourth toe (15–17 versus 19–24); from G. grossmanni Günther, 1994 by the absence of dorsal tubercle rows, having a higher number of ventrals (35 or 36 versus 26–31), and by a higher number of interorbitals (45–58 versus 38–46); from G. palmatus Boulenger, 1907 by the absence of dorsal tubercle rows, having fewer precloacal pores (10 or 11 versus 24–32), more interorbitals (45–58 versus 33–47), as well as by lacking well developed webbing between fingers and toes (as is present in G. palmatus ); from G. reevesii Gray, 1831 by a distinctly smaller body length (maximum 95.9 mm versus 173.0 mm), by the absence of dorsal tubercle rows (versus 12–18 in G. reevesii ), having a lower count of precloacal pores (10 or 11 versus 13–20), more interorbitals (45–58 versus 16–28), and by a lower count of subdigital lamellae below the fourth toe (15–17 versus 18– 24); from G. russelltraini Ngo, Bauer, Wood & Grismer, 2009 by the absence of dorsal tubercle rows (versus 12–16 in G. russelltraini ), more interorbitals (45–58 versus 30–34), a higher number of scales around the middle of the body (131–143 versus 90–107), and by having more ventrals (35–36 versus 28–30); from G. takouensis Ngo & Gamble, 2009 by the absence of dorsal tubercle rows (versus 14–17 in G. takouensis ), more interorbitals (45–58 versus 27–34), a lower count of subdigital lamellae below the fourth toe (15–17 versus 18–20), and by the number of postcloacal tubercles in males (1 versus 2 or 3 on each side in G. takouensis ); from G. vietnamensis Nguyen, 2010 by the absence of dorsal tubercle rows, having precloacal pores (which are completely absent in G. vietnamensis ), more interorbitals (45–58 versus 38–46), and by having more ventrals (35–36 versus 28–30). G. scientiadventura Rösler, Ziegler, Vu, Herrmann & Böhme, 2005 , so far is the only other Gekko species from Vietnam which also is lacking dorsal tubercles; from this latter species, Gekko truongi sp. n. differs by a larger body and total length (maximum 95.9 and 204.6 mm versus maximum 80.4 and 178 mm in G. scientiadventura ), a higher number of precloacal pores (10–11 versus 5–8), a lower ventral count (35–36 versus 38–48), and by a lower number of postcloacal tubercles (0 or 1 versus 2 or 3 on each side in G. scientiadventura ).

With respect to the remaining Gekko , Gekko truongi sp. n. differs from the following species by the absence of dorsal tubercle rows (see Ota et al. 1995; Rösler et al. 2005, 2006; Bauer et al. 2008; Toda et al. 2008; Zhou & Wang 2008; Brown et al. 2008, 2009; Linkem et al. 2010; Nonn et al. 2010): G. albofasciolatus Günther, 1867 ; G. auriverrucosus Zhou & Liu, 1982 ; G. carusadensis Linkem, Siler, Diesmos, Sy & Brown, 2010 ; G. chinensis (Gray, 1842) ; G. crombota Brown, Oliveros, Siler & Diesmos, 2008 ; G. e r n s t k e l l e r i Rösler, Siler, Brown, Demeglio & Gaulke, 2006; G. gigante Brown & Alcala, 1978 ; G. hokouensis Pope, 1928 ; G. japonicus (Schlegel, 1836) ; G. kikuchii Oshima, 1912 ; G. lauhachindai Nonn, Sumontha, Konlek & Kunya, 2010 ; G. liboensis Zhou & Li, 1982 ; G. mindorensis Taylor, 1919 ; G. monarchus (Schlegel, 1836) ; G. nutaphandi Bauer, Sumontha & Pauwels, 2008 ; G. palawanensis Taylor, 1925 ; G. petricolus Taylor, 1962 ; G. porosus Taylor, 1922 ; G. romblon Brown & Alcala, 1978 ; G. rossi Brown, Oliveros, Siler & Diesmos, 2009 ; G. scabridus Liu & Zhou, 1982 ; G. shibatai Toda, Sengoku, Hikida & Ota, 2008 ; G. siamensis Grossmann & Ulber, 1990 ; G. similignum Smith 1923 ; G. smithii Gray, 1842 ; G. swinhonis Günther, 1864 ; G. taylori Ota & Nabhitabhata, 1991 ; G. verreauxi Tytler, 1864 ; G. vertebralis Toda, Sengoku, Hikida & Ota, 2008 ; G. vittatus Houttuyn, 1782 ; G. wenxianensis Zhou & Wang, 2008 ; and G. yakuensis Matsui & Okada, 1968 .

According to the English summary of the Chinese original description of G. taibaiensis Song, 1985 , this species is closely related to G. swinhonis and G. japonicus ( Song 1985) , which both have dorsal tubercles. From these species, G. taibaiensis differs by fewer precloacal pores (4–6) which are arranged in an interrupted order. The maximum SVL of G. taibaiensis is 69 mm, and there are 7–8 subdigital lamellae under the fourth toe ( Zhao et al. 1999). G. taibaiensis thus differs from Gekko truongi sp. n. by its smaller size, its significantly smaller number of subdigital lamellae under the 4th toe (7–8 versus 15–17), and by the series of precloacal pores (4–6 versus 10–11 in Gekko truongi sp. n.) which is in addition medially interrupted by a smooth scale.

There are only few species in the genus Gekko that lack dorsal tubercles as in Gekko truongi sp. n. These are the aforementioned G. scientiadventura , G. athymus Brown & Alcala, 1962 , G. m e l l i Vogt 1922, G. subpalmatus Günther, 1864 , and G. tawaensis Okada, 1956 . According to the recent overview by Rösler et al. (2011), Gekko truongi sp. n. differs from all of them in the number of lamellae under the fourth toe: 15–17 in the new species versus 18–22 in G. a t h y m u s, 12–14 in G. m e l l i, 7–10 in G. subpalmatus , and 12 in G. t a w a e n s i s. Maximum body length is larger in G. a t h y m u s (119.9 versus 95.9 mm in Gekko truongi sp. n.). G. athymus further has a distinctly higher number of precloacal pores in males (20–24 versus 10–11 in Gekko truongi sp. n.). In contrast, precloacal pores are completely absent in G. t a w a e n s i s. Maximum body length is smaller in G. subpalmatus (72 mm) and G. t a w a e n s i s (71 mm), versus 95.9 mm in Gekko truongi sp. n. G. m e l l i has a lower number of scales along the underside of body from mental to cloacal slit (147–158 versus 160–172 in Gekko truongi sp. n.). The number of interorbitals is lower in G. m e l l i (35–39) and G. subpalmatus (32) versus 45–58 in Gekko truongi sp. n. The ventral count is higher in G. melli (43–49) and G. subpalmatus (48) versus 35–36 in Gekko truongi sp. n. The number of dorsal scale rows in the middle of the third caudal whorl is 7 in the holotype of G. subpalmatus and 9 in two type specimens of G. melli (see Rösler et al. 2005) versus 11 in Gekko truongi sp. n. G. subpalmatus has 8–12 supralabials and 7–9 lamellae under the first toe versus 13–15 supralabials and 11–13 lamellae under the first toe in Gekko truongi sp. n. G. m e l l i and G. subpalmatus furthermore differ from Gekko truongi sp. n. by their distinctly banded dorsal pattern and by the presence of light postocular stripes; they also differ from Gekko truongi sp. n. by the absence of enlarged postmentals (see Rösler et al. 2005: 142; Rösler et al. 2011).

Etymology. It is a pleasure for us to name this new species in honor of our friend and colleague Dr. Truong Quang Nguyen from the Institute of Ecology and Biological Resources in Hanoi, in recognition of his numerous and groundbreaking scientific contributions towards a better understanding of the amphibian and reptilian fauna of Vietnam. As common names we suggest Truong’s Gecko (English) , Tắc kè trường (Vietnamese), and Truongs Gecko ( German) .

Distribution. The species is currently known only from the type locality (Cuc Dong Cape, Ninh Hoa District, Khanh Hoa Province) in southern Vietnam ( Fig. 5).

Ecological notes. The type series was found in primary coastal vegetation slightly above sea level ( Fig. 6 ). The predominant vegetation, which is interspersed with large granit boulders, consists of small prickly shrubs and species of the families Ebenaceae and Dipterocarpaceae , but also Annonaceae , and Fabaceae . Specimens were collected at night, when they have left their shelters between stones and rocks. The stomach of the holotype contained the remains of large insects: An in total 61.6 mm long and up to 10.0 mm wide caterpillar and an in total 85.0 mm long stick insect were recovered. The right testis of the holotype measured 6.2 mm in length, and that of the paratype 5.8 mm. The female paratype contained two large eggs with maximum diameter of 7.6 mm.

Figures

FIGURE 1. Left (A) and right (B) side of the male holotype of Gekko truongi sp. n. (IEBR A. 2011.1) from Khanh Hoa Province. Photos T. M. Phung

FIGURE 2. Dorsal aspects of Gekko truongi sp. n. from Khanh Hoa Province: Male paratype (ZFMK 92292) in life (A) and female paratype (IEBR A. 2011.2) in preserved state (B). Photos T. M. Phung and T. Ziegler.

FIGURE 3. Dorsal view (A) and lateral view (B) of the head, gular region (C), and dorsum (D) of the male holotype of Gekko truongi sp. n. (IEBR A. 2011.1). Photos T. Ziegler.

FIGURE 4. Cloacal region of the male holotype of Gekko truongi sp. n. (IEBR A. 2011.1); position of precloacal pores marked with black. Photos T. Ziegler.

FIGURE 6. Habitat of Gekko truongi sp. n. at the type locality (Cuc Dong Cape, Ninh Hoa District, Khanh Hoa Province). Photos T. M. Phung.

Tables

TABLE 1. Measurements (in mm) and proportions of the type series of Gekko truongi sp. n. (for abbreviations see material and methods; * tail partially regenerated)

Sex SVL TL AG HL HW HH SE EE RW	IEBR A.2011.1 male 92.5 112.1 41.5 23.9 16.9 10.0 10.5 8.3 3.5	ZFMK 92292 male 95.9 99.7* 43.1 24.9 16.5 9.5 11.4 8.6 3.6	IEBR A.2011.2 female 89.8 79.3* 40.3 22.9 15.5 9.0 9.7 8.2 3.6	Mean±SD (variation) — 92.7±3.1 (89.8–95.9) 97.0±16.6 (79.3*–112.1) 41.6±1.4 (40.3–43.1) 23.9±1.0 (22.9–24.9) 16.3±0.7 (15.5–16.9) 9.5±0.5 (9.0–10.0) 10.5±0.9 (9.7–11.4) 8.4±0.2 (8.2–8.6) 3.6±0.1 (3.5–3.6)
RH MW ML SVL/TL	1.6 2.4 2.2 0.8	1.8 2.7 2.0 —	1.8 2.4 2.1 —	1.7±0.1 (1.6–1.8) 2.5±0.2 (2.4–2.7) 2.1±0.1 (2.0–2.2) 0.8
SVL/AG	2.2	2.2	2.2	2.2
SVL/HL	3.9	3.9	3.9	3.9
HL/HW HL/HH	1.4 2.4	1.5 2.6	1.5 2.4	1.5±0.1 (1.4–1.5) 2.5±0.1 (2.4–2.6)
SE/EE RW/RH	1.3 2.2	1.3 2.0	1.2 2.0	1.3±0.1 (1.2–1.3) 2.1±0.1 (2.0–2.2)
MW/ML RW/MW	1.1 1.5	1.4 1.3	1.1 1.5	1.2±0.2 (1.1–1.4) 1.4±0.1 (1.3–1.5)