Cyrtodactylus arndti, Ngo & Hormann & Pham & Phung & Ostrowski & Nguyen & Ziegler, 2023

Ngo, Hanh Thi, Hormann, Helene, Le, Minh Duc, Pham, Cuong The, Phung, Trung My, Do, Dang Trong, Ostrowski, Sabrina, Nguyen, Truong Quang & Ziegler, Thomas, 2023, The discovery of two new species in the Cyrtodactylus irregularis group highlights that hidden diversity remains in the largest clade of the mega-diverse genus Cyrtodactylus, European Journal of Taxonomy 875 (1), pp. 70-100 : 84-94

Cyrtodactylus arndti sp. nov.

urn:lsid:zoobank.org:act:83F60753-8E51-49D9-97E7-BD870AC772F3

Figs 6–9 ; Table 3

Diagnosis

The new species of Cyrtodactylus is distinguished from remaining congeners of the C. irregularis species group by a combination of the following characters: SVL: 73.4–80.9 mm; dorsal pattern with 6 or 7 irregularly shaped bands; moderately broad nuchal band; original tail with irregular transverse bands; subcaudals transversely enlarged; 5–11 enlarged femoral scales; males with 0–2 pitted femoral pores, those absence in females; males with 6 precloacal pores, females with 6 pitted precloacal pores, pore-bearing scales arranged in a single ˄-shaped series; ventral scales 26–38; dorsal tubercles in 17–20 irregular longitudinal rows; precloacal groove absent; supralabials 8–13; infralabials 8–12; number of subdigital lamellae on fourth finger 15–20 and on fourth toe 17–22.

Etymology

We name this species in honor of our colleague, Prof. Dr. Hartmut Arndt, Institute of Zoology, University of Cologne, Germany, in recognition of his support for biodiversity research in Vietnam. As common names, we suggest Arndt’s Bent-toed Gecko (English) and Thằn lằn ngón arndt (Vietnamese).

Type material ( Figs 6–9 )

Holotype

VIETNAM • ♂; Binh Dinh Province, Van Canh District, near Hiep Ha Village ; 13°39.858′ N, 108°53.355′ E; 270 m a.s.l.; 13 Aug. 2016; D.T. Do and T.V. Nguyen; Field No. BD.2016.141; IEBR R.4930 .

Paratypes

VIETNAM • 1 ♂; Binh Dinh Province, Quy Nhon District, Quy Nhon City ; 13°41.718′ N, 109°10.277′ E; 140 m a.s.l; 8 Aug. 2016; D.T. Do and T.V. Nguyen; Field No. BD.2016.1; IEBR R.5219 • 2 ♂♂, 1 ♀; Binh Dinh Province, Van Canh District, near Dak Dum Village ; 13°38.365′ N, 108°57.863′ E; 150 m a.s.l.; 11 Aug. 2016; D.T. Do and T.V. Nguyen; Field No. BD.2016.86, BD2016.87, BD.2016.88; IEBR R.4931 to IEBR.4933 • 1 ♀; Binh Dinh Province, Van Canh District, near Hiep Ha Village ; 13°39.858′ N, 108°53.355′ E; 270 m a.s.l.; D.T. Do and T.V. Nguyen; Field No. BD.2016.86; IEBR R.5077 • 2 ♂♂; same collection data as for preceding; Field No. BD.2016.142, BD.2016.143; ZFMK 103910 , ZFMK 103911 .

Description of holotype

Adult male; snout-vent length 74.4 mm; tail regenerated, 98.15 mm in length; body slender, elongate (AG/SVL ratio 0.39); head distinct from neck, elongate, depressed (HL/SVL 0.29, HW/HL 0.67, HH/ HL 0.37); loreal region concave; snout long, blunt in dorsal profile (SE/HL 0.37), longer than diameter of orbit (OD/SE 0.61); scales on snout small, round or oval, granular, lager than scales on occiput; orbit large (OD/HL 0.22); pupils vertical; ear opening small, oval (ED/HL 0.06); rostral almost twice as wide as high with an inverse Y-shapted structure, surrounded by first supralabial, naris, nasorostral on each side, and internasal; nostril opening small and oval, surrounding by rostral, nasorostral, 2 supranasals and one postnasal; mental scale triangular, wider than high (ML/MW 0.74); two enlarged, triangular postmentals; supralabials 12/12; infralabials 11/13.

Dorsal scales granular, dorsal tubercles round, keeled, conical, in 20 irregular rows at midbody; tubercles on occiput small; each tubercle surrounded by 9 or 10 granular scales; ventral scales smooth, round, midventral scales approximately 3–4 times as large as dorsal scales, slightly imbricate laterally, in 37 longitudinal rows at midbody between ventrolateral folds; precloacal groove absent; enlarged femoral scales 7 or 8 on each thigh, about twice the size of surrounding scales; enlarged precloacal scales 17, arranged in a rhombus; femoral pores absent; precloacal pores 6, arranged in ˄-shaped series.

Fore and hindlimbs moderately slender (ForeaL/SVL 0.15 mm, CrusL/SVL 0.16); forelimbs dorsally covered by several slightly enlarged tubercles; dorsal surface of hindlimbs bearing well-developed tubercles; two postcloacal tubercles on each side on the hemipenal swellings; phalanges without webbing; each claw sheathed by two scales, the ventral sheath larger than the upper scale; number of subdigital lamellae on first finger 12/13, on first toe 13/13, on fourth finger 18/18, on fourth toe 22/22.

Coloration in preservative

Dorsal surface of head, body and limbs light-brown with some dark-brown pattern, without light bordering; occiput marbled with small, irregular dark-brown banded; rostral, mental, first three supralabials and first infralabials greyish brown, remaining infralabials light beige, some with greyish brown speckles or frames; nuchal band discontinuous, consisting of two stripes extending from the orbits to the neck, ending by a dark blotch on each side and a third blotch medially; dorsum with 7 irregular bands, the first two interrupted; dorsolateral region covered with round or elongate dark-brown blotches; tail with 6 dark-brown bands, fade ventrally, some small dark-brown spots arranged in a line along the lateral side of tail, tail tip dark-brown; dorsal surface of limbs with 6 or 7 irregular dark-brown bands; phalanges brown with beige knuckles; dorsal tubercles white or dark-brown depending on position; tubercles on dorsal surface of limbs and tail light-brown; venter greyish brown.

Sexual dimorphism and variation

The female (IEBR R.4933) differs from the males by the absence of hemipenal swellings. All male specimens have 6 precloacal pores but the females has 6 pitted scales only. Three males (IEBR R.4930, ZFMK 103910, ZFMK 103911) and the female lack femoral pores (IEBR R.5077, IEBR R.4933). For further morphological characters see Table 3 .

Comparisons

The new species can be distinguished from all other member of Cyrtodactylus irregularis group from Vietnam by morphological characteristics (see Table 4 ).

Cyrtodactylus arndti sp. nov. differs from C. badenensis by having the presence of enlarged femoral scales (5–11 vs absent in C. badenensis ), the presence of precloacal pores in males (6 vs absent in C. badenensis ), the presence of pitted precloacal pores in females (6 vs absent in C. badenensis ), and different dorsal pattern (irregular bands vs banded in C. badenensis ); differs from C. bidoupimontis by having the presence of pitted precloacal pores in females (6 vs absent in C. bidoupimontis ), having moderately broad nuchal band, continuous or discontinuous band (vs well developed, widened posteriorly in C. bidoupimontis ), different dorsal pattern (6 or 7 irregular transverse bands, colouration dark-brown on light-brown background vs 4–5 dark irregular transverse dorsal bands, usually with light borders), and the presence of transversely enlarged subcaudals vs absent in C. bidoupimontis ; differs from C. bugiamapensis by having fewer precloacal pores in males (6 vs 7–11 in C. bugiamapensis ), different dorsal color pattern (irregular, dark-brown transverse bands vs unclear transversal bands formed by irregular roundish to oblong, dark brown spots in C. bugiamapensis ), moderately broad nuchal band, continuous or discontinuous bands (vs dark nuchal band, which can be medially divided, narrow, U-shape in C. bugiamapensis ), and the presence of transversely enlarged subcaudals vs absent in C. bugiamapensis ; differs from C. buchardi by having a lagger size (SVL of 73.4–80.9 vs 60–65 in C. buchardi ), the presence of enlarged femoral scales (5–11 vs absent in C. buchardi ), more subdigital lamellae on first finger (15–20 vs 14 in C. buchardi ), more subdigital lamellae on first toe (17–22 vs 12 in C. buchardi ) and the presence of transversely enlarged subcaudals vs absent in C. buchardi ); differs from C. caovansungi by having a smaller size (SVL of 73.4–80.9 vs 90.4–94.0 mm), fewer femoral pores (0–2 vs 6 in C. caovansungi ), fewer precloacal pores in males (6 vs 9 in C. caovansungi ), the presence of pitted precloacal pores in females (6 vs absent in C. caovansungi ), and fewer subdigital lamellae under the fourth toe (17–22 vs 23–25 in C. caovansungi ); differs from C. cattienensis by having a larger size (73.4–80.9 mm vs 43.5–69.0 mm in C. cattienensis ), the presence of pitted precloacal pores in females (6 vs absent in C. cattienensis ), and the presence of transversely enlarged subcaudals (vs absent in C. cattienensis ); differs from C. chungi by having a larger size (73.4–80.9 mm vs 66.6– 68.5 mm in C. chungi ), fewer precloacal pores in males (6 vs 7 in C. chungi ), fewer enlarged precloacal scales (17–23 vs 41–45 in C. chungi ), and the presence of transversely enlarged subcaudals (vs absent in C. chungi ); differs from C. cryptus by having fewer ventral scale rows (26–38 vs 47–50 in C. cryptus ), the presence of enlarged femoral scales (5–11 vs absent in C. cryptus ), fewer precloacal pores in males (6 vs 9–11 in C. cryptus ), the presence of pitted precloacal pores in females (6 vs absent in C. cryptus ), and the presence of transversely enlarged subcaudals (vs absent in C. cryptus ); differs from C. cucdongensis by having a larger size (SVL 73.4–80.9 mm vs 55.8–65.9 mm in C. cucdongensis ), fewer ventral scale rows (26–38 vs 41–44 in C. cucdongensis ), more subdigital lamellae under the first toe (11–14 vs 8–11 in C. cucdongensis ), and the presence of transversely enlarged subcaudals (vs absent in C. cucdongensis ); differs from C. culaochamensis by having fewer ventral scale rows (26–38 vs 45– 50 in C. culaochamensis ), the presence of enlarged femoral scales (5–11 vs absent in C. culaochamensis ), fewer precloacal pores in males (6 vs 7–8 in C. culaochamensis ), and the presence of pitted precloacal pores in females (6 vs absent in C. culaochamensis ); differs from C. dati by having fewer ventral scale rows (26–38 vs 42–48 in C. dati ), fewer femoral pores (0–2 vs 3–4 on each side in C. dati ), different dorsal color pattern (irregular bands vs blotches in C. dati ), and the presence of transversely enlarged subcaudals (vs absent in C. dati ); differs from C. gialaiensis by having a larger size (73.4–80.9 mm vs 50.1–62.8mm in C. gialaiensis ), the presence of enlarged femoral scales (5–11 vs absent in C. gialaiensis ), fewer precloacal pores in males (6 vs 9–10 in C. gialaiensis ), and more subdigital lamellae under the fourth finger (15–20 vs 14–15 in C. gialaiensis ); differs from C. huynhi by having fewer ventral scale rows (26–38 vs 43–46 in C. huynhi ), more enlarged femoral scales (5–11 vs 3–5 in C. huynhi ), fewer precloacal pores in males (6 vs 7–9 in C. huynhi ), and the presence of transversely enlarged subcaudals (vs absent in C. huynhi ); differs from C. irregularis by having the presence of precloacal pores in males (1–2 vs absent in C. irregularis ), different dorsal color pattern (irregular bands vs blotched in C. irregularis ), and the presence of transversely enlarged subcaudals (vs absent in C. irregularis ); differs from C. kingsadai by having a smaller size (SVL 73.4–80.9 mm vs 83.0–94.0 mm in C. kingsadai ), fewer ventral scale rows (26–38 vs 39–46 in C. kingsadai ), and fewer precloacal pores in males (6 vs 7–9 in C. kingsadai ); differs from C. orlovi by having a larger size in males (SVL 73.4–80.9 mm vs 61.0– 68.2 mm in C. orlovi ), the presence of pitted precloacal pores in females (6 vs absent in C. orlovi ), and the presence of transversely enlarged subcaudals(vs absent in C. orlovi ); differs from C.phnomchiensis by having fewer ventral scale rows (26–38 vs 45–54 in C. phnomchiensis ), more precloacal pores in males (6 vs 4–5 in C. phnomchiensis ), fewer AG/SVL ratio (0.34–0.43 vs 0.45–0.48 in C. phnomchiensis ), and the presence of transversely enlarged subcaudals (vs absent in C. phnomchiensis ); differs from C. phumyensis by having a larger size (SVL 73.4–80.9 mm vs 63.6–66.8 mm in C. phumyensis ), and the presence of transversely enlarged subcaudals (vs absent in C. phumyensis ); differs from C. phuocbinhensis by having a larger size (SVL 73.4–80.9 mm vs 46.0– 60.4 mm in C. phuocbinhensis ), fewer ventral scale rows (26–38 vs 43–47 in C. phuocbinhensis ), fewer precloacal pores in males (6 vs 7 in C. phuocbinhensis ), the presence of pitted precloacal pores in females (6 vs absent in C. phuocbinhensis ); differs from C. pseudoquadrivirgatus by having fewer ventral scale rows (26–38 vs 41–57 in C.pseudoquadrivirgatus ), the presence of enlarged femoral scales (5–11 vs absent in C. pseudoquadrivirgatus ), different dorsal color pattern (irregular bands vs blotched in C. pseudoquadrivirgatus ), and the presence of transversely enlarged subcaudals (vs absent in C. pseudoquadrivirgatus ); differs from C. raglai by having a smaller size (SVL 73.4–80.9 mm vs 95–111.7 mm in C. raglai ), more precloacal pores in males (6 vs 5 in C. raglai ) and the presence of pitted precloacal pores in females (6 vs absent in C. raglai ); differs from C. sangi by having a larger size (SVL 73.4–80.9 mm vs 49.9–56.3 mm in C. sangi ), more enlarged femoral scales (5–11 vs 4 in C. sangi ), fewer precloacal pores in males (6 vs 7 in C. sangi ), and more pitted precloacal pores in females (6 vs 4 in C. sangi ); differs from C. takouensis by having more enlarged femoral scales (5–11 vs 3–5 in C. takouensis ), more precloacal pores in males (6 vs 3–4), the presence of pitted precloacal pores in females (6 vs absent in C. takouensis ), and the different dorsal color pattern (irregular bands vs banded in C. takouensis ); differs from C. taynguyenensis by having more ventral scale rows (26–38 vs 42–49 in C. taynguyenensis ), the presence of enlarged femoral scales (5–11 vs absent in C. taynguyenensis ), the different dorsal color pattern (irregular bands vs blotched in C. taynguyenensis ), and the presence of transversely enlarged subcaudals (vs absent in C. taynguyenensis ); differs from C. yangbayensis by having the presence of pitted precloacal pores in females (6 vs absent in C. yangbayensis ), more subdigital lamellae under the fourth toe (17–22 vs 15–17), and fewer subdigital lamellae on first toe (11–14 vs 18–20 in C. yangbayensis ); differs from C. ziegleri by having a smaller size (SVL 73.4–80.9 mm vs 84.6–93.0 mm in C. ziegleri ), the presence of transversely enlarged subcaudals (vs absent in C. ziegleri ), and dark-brown transverse bands of the tail narrower than the light-brown interspaces (vs dark transverse bands wider than the light interspaces in C. ziegleri ).

Differs from C. chumuensis sp. nov. by having a larger size (SVL 73.4–80.9 mm vs maximum 67.5 mm in C. chumuensis ), fewer ventral scale rows (26–38 vs 43–45 in C. chumuensis ), and the presence of transversely enlarged subcaudals (vs absent in C. chumuensis ).

Distribution

Cyrtodactylus arndti sp. nov. is currently known only from the Van Canh District, Binh Dinh Province, Vietnam ( Fig. 1 ).

Natural history

Specimens were found at night between 19:00 and 22:00, on trees or on granite rock, along rocky streams, about 0.6–1.5 m above the ground, at elevations between 150 and 300 m a.s.l. The surrounding habitat was evergreen forest of medium and small hardwoods mixed with shrubs and vines ( Fig. 9 ). The humidity was approximately 40–62% and the air temperature ranged from 28.9 to 33.1 ° C. Other reptiles species found at the sites included Acanthosaura coronata (Günther, 1861) Dixonius vietnamensis Das, 2004 , Gekko gecko (Linnaeus, 1758) , Gekko sp. , Eutropis multifasciata (Kuhl, 1820) , Boiga jaspidea (Duméril, Bibron & Duméril, 1854) , Psammodynastes pulverulentus (Boie, 1827) , and Trimeresurus sp.

Figures

Fig. 6. Cyrtodactylus arndti sp. nov., holotype, ♂ (IEBR R.4930), in life.

Fig. 7. Cyrtodactylus arndti sp. nov., paratypes ♂♂ (IEBR R.4931, IEBR R.4932), in life.

Fig. 8. Cyrtodactylus arndti sp. nov., type series in preservative (the holotype is the third from right).

Fig. 9. Habitat of Cyrtodactylus arndti sp. nov. in Hiep Ha Village, Van Canh District, Binh Dinh Province.

Fig. 1. Type locality of Cyrtodactylus chumuensis sp. nov. in Dak Lak Province (black circle) and Cyrtodactylus arndti sp. nov. in Binh Dinh Province (black triangle), Vietnam.