Cyrtodactylus chungi, Ostrowski & Ngo & Pham & Phung & Nguyen & Ziegler, 2021

Ostrowski, Sabrina, Le, Minh Duc, Ngo, Hanh Thi, Pham, Cuong The, Phung, Trung My, Nguyen, Truong Quang & Ziegler, Thomas, 2021, A new Cyrtodactylus (Squamata: Gekkonidae) from Binh Thuan Province, southern Vietnam, European Journal of Taxonomy 731, pp. 47-70 : 53-64

Cyrtodactylus chungi sp. nov.

urn:lsid:zoobank.org:act:C3B181E8-F9D3-4344-AD20-28765D1BA0B2

Figs 3–8

Diagnosis

The new species can be distinguished from other members of the genus Cyrtodactylus by a combination of the following characters ( Table 1 ): relatively small body size (SVL up to 68.5 mm); a continuous neckband; 5 or 6 irregular transverse dorsal bands; 11 or 12 bands on original tail; keeled tubercles present on dorsum, posterior limbs and tail; 17 or 18 irregular dorsal tubercle rows; 30 or 31 ventral scale rows; ventrolateral skin folds indistinct; an angular series of seven precloacal pores in male and six pitted, enlarged precloacal scales in female, each series separated by a diastema of undifferentiated scales from 4–6 enlarged, poreless femoral scales; median subcaudals slightly enlarged; 17–20 subdigital lamellae under the fourth toe.

Etymology

Specific epithet ‘ chungi ’ is in honor of Prof. Dr Ngo Dac Chung, College of Education, Hue University, in recognition of his outstanding contributions to training of many herpetologist generations from Hue University. For the common names we suggest Chung’s Bent-toed Gecko (English) and Thạch sùng ngón chứng (Vietnamese).

Type material ( Figs 3–8 )

Holotype VIETNAM • ♂; Southern Vietnam, Ham Thuan Nam District, Binh Thuan Province, Ta Kou Nature Reserve ; 10 o 48.868′ N, 107 o 53.523′ E; 424 m a.s.l.; 20 Jun. 2017; T.M. Phung leg.; Field No. BT2017.1; sequence with GenBank accession number MT576019 ; IEBR 4581 .

Paratype

VIETNAM • 1 ♀; same collection data as for holotype; Field No. BT2017.2; sequence with GenBank accession number MT576020 ; IEBR 4582 .

Description of holotype

Adult male, snout-vent length (SVL) 66.6 mm; tail length (TL) 62.7 mm (45.1 mm regenerated); head distinct from neck, relatively long (HL: 20.1 mm; HL/SVL ratio 0.32), HW 13.3 mm (HW/ HL ratio 0.66), HH 7.8 mm (HH/HL ratio 0.4); loreal region slightly bulged; snout elongated and rounded (SE: 7.6; SE/HL ratio 0.38); eye diameter 4.4 mm, more than half of snout-eye distance (OD/SE ratio 0.58); median snout scales small and rounded; eyes relatively small compared to head (OD/HL ratio 0.22); anterior supraciliaries large and rounded, posterior supraciliaries small and tapered; ear openings relatively small (ED: 0.75 mm; ED/HL ratio 0.04), vertical and oval in shape; eye to ear distance slightly longer than eye diameter (EyeEar/ED ratio 1.39); rostral wider than high (RH: 1.65 mm; RW: 3.3 mm; RW/RH ratio 2), with an inverse, Y-shaped median suture, surrounded by first supralabial, two nostrils, two supranasals and internasal; lateral nostrils elongated, oval and surrounded by rostral, first supralabial, three postnasals and one supranasal; supranasals separated by one internasal; eye separated from supralabials by 3 or 4 scale rows; mental triangular, wider than high (MW: 1.75 mm; MH 2.6 mm; MW/MH ratio 1.49), surrounded by first two infralabials and posteriomedially by postmentals; supralabials 10/9; infralabials 9/9; body slender and short (AG/SVL ratio 0.41); ventrolateral skin folds not developed; dorsal scales granular, heterogeneous in shape and size; dorsal tubercles present in posterior part of head, extremities, dorsum and first third of tail; postocular tubercles irregularly distributed, rounded, flat and about three times size of surrounding granular scales; median dorsal tubercles about five times as large as granular scales, oval, and not keeled; posterior dorsal tubercles keeled and on sacral region very strongly keeled up to base of tail; 18 irregular transversal dorsal tubercle rows; 24 paravertebral tubercles; each tubercle surrounded by 9 or 10 granular scales; ventrals smooth, oval and slightly imbricate, in 31 longitudinal rows; gular scales homogeneous; dorsal surfaces of upper and lower arms without tubercles, but occasionally enlarged granular scales; left thigh with series of 6 enlarged femoral scales separated by diastema of 6 smaller scales from precloacal scales; right thigh with series of 3 enlarged femoral scales separated by diastema of 8 smaller scales from precloacal scales and single enlarged femoral scale distally; no femoral pores; 45 enlarged precloacal scales arranged in diamond shape, with angled series of 7 pore-bearing scales (3 right, 1 angled, 3 left); 15 posteriorly enlarged scales and 21 anteriorly enlarged scales; two postcloacal tubercles on each side; scales on palms and soles rounded to oval, smooth and arched; fore- and hindlimbs moderately long (ForeaL/SVL ratio 0.15; Tibia/SVL ratio 0.17) relatively narrow; toes and fingers narrow and curved at interphalangeal joint; slightly transparent, pointed and curved claws, bordered ventrally by large lamella and dorsally by small, narrow scale; subdigital lamellae proximally larger, widened and merge basally into smaller scales of palm and sole surfaces; distal lamellae smaller, more elongated and distally increasingly imbricate; right fourth finger with 15 subdigital lamellae (6 proximal, 9 distal); left fourth finger with 16 subdigital lamellae (5 proximal, 11 distal); right and left fourth toe with 17 subdigital lamellae each (6 proximal, 11 distal); base of tail with small granular supracaudals and strongly keeled, rounded tubercles; last two thirds of tail regenerated, scales heterogeneously arranged and shaped; tubercles of original part arranged in 6 transverse rows (8/-/4/4/4/4) in a distance of 6–7 granular scale rows; tubercles slightly keeled; subcaudals of original part oval, rounded and imbricate; median subcaudals about two to three times larger than the lateral scales, but not transversely enlarged, or arranged in definable rows.

Coloration in preservative ( Figs 5–8 )

Ground color of head, neck, limbs and tail grey to light brown; dorsal surface of head brown with irregular, small, dark brown spots; two larger dark brown blotches located in posterior interorbital area and two other dark brown blotches in occiput area; skin above eyes dark grey, blue to black; rostral dark brown; supralabials and infralabials also brown, turning to cream at adjacent areas; a distinct dark brown stripe in loreal region, reaching to third supralabial; nuchal loop dark brown, in V-shape, extending from posterior corner of eye to the neck, edged in light grey; tubercles on head, limbs, dorsum and tail light to dark brown; tubercles on lateral skin fold white to gray; dorsal surfaces of limbs with small, irregularly distributed, dark brown spots; dorsal surface of toes and fingers dark brown spotted with light grey; dorsum with 5 irregular transverse dark brown bands; first band over the shoulder region, X-shaped; dark and light brown spots present between transverse bands and on flanks; ventral scales of body light grey to cream; lateral sides of head, below postocular stripe, and ventrolateral margins of flanks slightly white to cream; anterior part of tail with two transverse, dark brown bands dorsally with dark brown spots in interspaces; dark, transverse dorsal bands separated from underside of tail by light brown, whitish spotted sides of tail; tail light grey to cream ventrally and marbled brown on the original part; regenerated part of tail grey to light brown, marbled.

Coloration in life

Ground color of dorsal surface of head, limbs and dorsum bright-yellow; transverse body and tail bands darker; lateral head and belly with bright-yellow spots; marbling of surface of limbs darker; ventral surface white to light blue ( Figs 3–4 ).

Sexual dimorphism and variation

The morphological characteristics of the female IEBR 4582 correspond well with the holotype (IEBR 4581) and differ only in a few details. The female has some slightly keeled tubercles on the dorsal surface of the forelimbs. Dorsal tubercles are keeled from the posterior insertion of the forelimbs. The two supranasals are separated by two internasals. Another internasal is inserted between the rostral and the two internasals. Two inverse sutures are X-shaped from the lower edges of the internasal and do not form a median suture. The tail is original. The median subcaudals are about twice as large as the supracaudals and extend to the tip of the tail. The two dark brown spots of the occiput are longer and larger. The neck band is also V-shaped but pointed posteriorly. The dorsal surfaces of the forearms and hindlimbs with fine, irregular, transverse stripes. Dorsum with 6 transverse, irregular bands. The first band, between the insertion of the forelimbs, is clearly X-shaped over the shoulder region. Between the neck band and the first body band is an oval, dark brown spot. The dorsal tubercles are clearly lighter. The dorsal side of the tail bears 11–12 transverse, dark brown bands, which completely enclose only the last third. Between these bands are irregular, fine, light brown to brown stripes and dots. The first two thirds of the underside of the tail are marbled light grey to brown. The last third resembles the dorsal side.

Comparison

We compared the new species with its 19 congeners from the Cyrtodactylus irregularis complex based on an examination of specimens ( Table 2 ) and data obtained from the literature ( Smith 1921 a, 1921b; Ziegler et al. 2002, 2013; Heidrich et al. 2007; Orlov et al. 2007; Nazarov et al. 2008. 2012; Ngo & Bauer 2008; Rösler et al. 2008; Geissler et al. 2009; Ngo & Chan 2010; Ngo 2013; Nguyen et al. 2013; Schneider et al. 2014; Luu et al. 2017; Pauwels et al. 2018; Neang et al. 2020; Ostrowski et al. 2020). The new species can be distinguished from all other Cyrtodactylus species from Vietnam by morphological characteristics (see Table 3).

In comparison with the species from the C. irregularis complex Cyrtodactylus chungi sp. nov. is distinguished from C. caovansungi Orlov, Nguyen, Nazarov, Ananjeva & Nguyen, 2007 , C. kingsadai Ziegler, Phung, Le & Nguyen, 2013 , C. takouensis Ngo & Bauer, 2008 and C. yangbayensis Ngo & Chan, 2010 by the absence of transversely enlarged subcaudals.

The new species can be distinguished from C. cryptus Heidrich, Rösler, Vu, Böhme & Ziegler, 2007 , C. gialaiensis Luu, Tran, Nguyen, Le & Ziegler, 2017 , C. pseudoquadrivirgatus Rösler, Nguyen, Vu, Ngo & Ziegler 2008 and C. taynguyenensis Nguyen, Le, Tran, Orlov, Lathrop Macculoch, Le, Jin, Nguyen, Nguyen, Hoang, Che, Murphy & Zhang, 2013 by the presence of enlarged femoral scales.

The new species can be distinguished from C. bidoupimontis Nazarov, Poyarkov, Orlov, Phung, Nguyen, Hoang & Ziegler, 2012 by its smaller size (SVL of 66.6–68.5 vs 74.0– 86.3 mm), fewer ventral scale rows (30–31 vs 38–43) and enlarged femoral scales (4–6 vs 8–10), more precloacal pores in the male (7 vs 4–6), the presence of 6 pitted precloacal scales in the female (vs absence) and by the different dorsal color patter (irregular transversal bands vs irregular transversal bands with light borders).

Cyrtodactylus chungi sp. nov. differs from C. bugiamapensis Nazarov, Poyarkov, Orlov, Phung, Nguyen, Hoang & Ziegler, 2012 by having fewer ventral scale rows (30–31 vs 36–46) and enlarged femoral scales (4–6 vs 6–8), and by the different dorsal color pattern (irregular transversal bands vs round spots forming irregular transverse bands).

Cyrtodactylus chungi sp. nov. differs from C. cucdongensis Schneider, Phung, Le, Nguyen & Ziegler, 2014 by its larger size (SVL 66.6–68.5 vs 55.8–65.9 mm), fewer ventral scale rows (30–31 vs 35–44) and enlarged femoral scales (4–6 vs 5–9).

Cyrtodactylus chungi sp. nov. differs from C. dati Ngo, 2013 by having fewer ventral scale rows (30–31 vs 42–48) and by the different dorsal color pattern (irregular transverse bands vs irregular dark blotches).

Cyrtodactylus chungi sp. nov. differs from C. huynhi Ngo & Bauer, 2008 by having fewer ventral scale rows (30–31 vs 43–46) and by the absence of femoral pores (vs 3–8).

Cyrtodactylus chungi sp. nov. differs from C. irregularis ( Smith, 1921) by its smaller size (SVL of 66.6–68.5 vs 72.0–86.0 mm), having fewer ventral scale rows (30–31 vs 38–45) and enlarged femoral scales (4–6 vs 7–8), and by the different dorsal color pattern (irregular transverse bands vs transverse bands with uneven margins in white binding, some bands can fall into separated spots).

Cyrtodactylus chungi sp. nov. differs from C. phnomchiensis Neang, Henson & Stuart, 2020 by its smaller size (SVL 66.6–68.5 vs 76.1–80.7 mm), having fewer ventral scale rows (30–31 vs 45–54) enlarged femoral scales (4–6 vs 0–8), precloacal pores in males (7 vs 4–5) and subdigital lamellae under the fourth to (17–20 vs 20–23) and by the different dorsal color pattern (irregular transverse brown bands vs dark brown body bands bordered by yellowish white or light brown bands).

Cyrtodactylus chungi sp. nov. differs from C. phumyensis Ostrowski, Do, Lee, Ngo, Pham, Nguyen, Nguyen & Ziegler, 2020 by having fewer ventral scale rows (30–31 vs 33–40), the absence of pitted precloacal scales in the male (absent vs 1), more paravertebral tubercles (24–27 vs 20–23) and by the different dorsal color pattern (irregular transverse bands vs anteriorly irregularly spotted and posteriorly banded).

Cyrtodactylus chungi sp. nov. differs from C. phuocbinhensis Nguyen, Le, Tran, Orlov, Lathrop Macculoch, Le, Jin, Nguyen, Nguyen, Hoang, Che, Murphy & Zhang, 2013 by its larger size (SVL 66.6–68.5 mm vs 46.0– 60.4 mm), having fewer ventral scale rows (30–31 vs 43–47), the presence of 6 pitted precloacal scales in the female (vs absence) and the different dorsal color pattern (irregular transversal bands vs stripes).

Cyrtodactylus chungi sp. nov. differs from C. ziegleri Nazarov, Orlov, Nguyen & Ho, 2008 by its smaller size (SVL of 66.6–68.5 vs 84.6–93.0 mm), having fewer ventral scale rows (30–31 vs 33–39) and enlarged femoral scales (4–6 vs 8–10).

Cyrtodactylus chungi sp. nov. is most similar to C. sangi Pauwels, Nazarov, Bobrov & Poyarkov, 2018 . However, the new species can be distinguished from C. sangi by its larger size (SVL 66.6–68.5 vs 49.9–56.3 mm), having fewer ventral scale rows (30–31 vs 37) and by the different dorsal color pattern (irregular transversal bands with a closed neck band vs irregular transversal bands and pattern with an interrupted neck band).

Distribution

Cyrtodactylus chungi sp. nov. is currently known only from the type locality in Ta Kou Nature Reserve, Binh Thuan Province, Vietnam ( Fig. 1 ).

Natural history

Specimens were found at night between 20:00 and 22:00, on granite rock nearby a forest path, about 0.5–1.0 m above the ground, at elevations between 400 and 500 m a.s.l. The surrounding habitat was evergreen forest of medium and small hardwoods mixed with shrubs and vines. The humidity was approximately 68–72% and the air temperature ranged from 26.8 to 31.6 oC ( Fig. 9 ).

Figures

Fig. 3. Cyrtodactylus chungi sp. nov. in life. Top: holotype, ♂ (IEBR 4581). Bottom: paratype, ♀ (IEBR 4582). Photos T.M. Phung.

Fig. 4. Cyrtodactylus chungi sp. nov., in life paratype, ♀ (IEBR 4582). Photos T.M. Phung.

Fig. 5. Cyrtodactylus chungi sp. nov., holotype, ♂ (IEBR 4581) and paratype, ♀ (IEBR 4582). Views in preservative. Top: dorsal view. Bottom: ventral view. Photos T. Ziegler.

Fig. 6. Cyrtodactylus chungi sp. nov., holotype, ♂ (IEBR 4581). Cloacal region in preservative. Photo T. Ziegler.

Fig. 7. Head views in preservative of Cyrtodactylus chungi sp. nov. from Ta Kou Nature Reserve, Binh Thuan Province, Vietnam. On the left: holotype, ♂ (IEBR 4581); on the right: paratype, ♀ (IEBR 4582). Top: lateral view. Bottom left: dorsal view. Bottom right: ventral view. Photos T. Ziegler.

Fig. 8. Cyrtodactylus chungi sp. nov., paratype, ♀ (IEBR 4582). Head views in preservative. Top: lateral view. Bottom left: dorsal view. Bottom right: ventral view. Photos T. Ziegler.

Fig. 1. Map of Vietnam showing the type locality of Cyrtodactylus chungi sp. nov. in Binh Thuan Province.

Fig. 9. Habitat of Cyrtodactylus chungi sp. nov. in Ta Kou Nature Reserve, Binh Thuan Province. Photo C.T. Pham.