Hemiphyllodactylus dalatensis, Do & Nguyen & Le & Pham & Ziegler & Nguyen, 2021

Do, Quyen Hanh, Nguyen, Khoi Vu, Le, Minh Duc, Pham, Cuong The, Ziegler, Thomas & Nguyen, Truong Quang, 2021, A new species of Hemiphyllodactylus Bleeker, 1860 (Squamata: Gekkonidae) from Da Lat Plateau, Vietnam, Zootaxa 5023 (1), pp. 93-106 : 97-103

Hemiphyllodactylus dalatensis sp. nov.

( Figs. 3 , 4 )

Holotype. IEBR R.4830 (Field number ASU/RWV 10843), adult male, collected on 10 May 2015 by K. V. Nguyen , near Giang Ly Ranger Station (12 o 10.954’N, 108 o 40.805’E, at an elevation of 1442 m a.s.l.), Bidoup - Nui Ba National Park , Da Chai Commune, Lac Duong District, Lam Dong Province, the Central Highlands of Vietnam.

Paratypes. Three specimens collected from the same locality as the holotype : IEBR R.4831 (Field number ASU/ RWV 10895) , IEBR R.4832 (Field number ASU/RWV 10913), adult males , IEBR R.4833 (Field number ASU/ RWV 10844), adult female; the same collection data as for the holotype .

Diagnosis. The new species from southern Vietnam differs from the remaining congeners of the genus Hemiphyllodactylus by a combination of the following characters: a bisexual taxon; a maximum SVL of 45.9 mm; dorsal scale rows 16; ventral scale rows 8 or 9; chin scales 7–10; postmental scales enlarged; femoral and precloacal pores in a continuous series, 23–25 in total in males, absent in the female; digital lamellae formula 4-5-5/6-5 (forefoot) and 5-6-6-6/5 (hind foot); cloacal spurs 2 or 3 on each side in both males and female; enlarged subcaudal scales absent; dorsal trunk pattern with two paravertebral stripes, formed by two rows of dark spots; dark lateral head stripe distinct; postsacral mark cream or orange and bearing anteriorly projecting arms.

Description of the holotype. Adult male, size small (SVL 43.4 mm); body compressed, trunk length (TrunkL 20.7 mm); tail regenerated (TailL 30.8 mm); head triangular in dorsal profile, longer than wide (HeadL 10.8 mm, HeadW 7.6 mm), distinct from neck; lores and interorbital regions flat; rostrum relatively long (NarEye/HeadL 0.33); eye large, pupils vertical (EyeD 2.6 mm), eye to ear distance longer than diameter of eye (EyeEar/EyeD 1.42); ear oval shaped, small (EarD 0.8 mm); nare-eye distance (NarEye 3.6 mm); snout moderate, round in dorsal profile, longer than eye diameter (EyeD/SnEye 0.54), snout-eye distance (SnEye 4.8 mm), internarial distance (SnW 1.5 mm). Proportions: Trunk/SVL 0.48, HeadL/SVL 0.25, HeadW/SVL 0.18, HeadW/HeadL 0.71, SnEye/HeadL 0.45, NarEye/HeadL 0.33, EyeD/HeadL 0.24, SnW/HeadL 0.14, EyeD/NarEye 0.72, SnW/HeadW 0.20.

Scalation: Rostral very large, wider than high, partially divided dorsally, bordered by first supralabial, nostril, and large supranasal on each side; supranasals separated from each other by two small scales; supralabials 11/11, enlarged from rostral to below eye, smaller in subocular rictus; nares round, surrounded by rostral anteriorly, first supralabial ventrally, supranasal dorsally and three nasals posteriorly on each side; pupil vertical, upper eyelid with small supraciliaries; ear opening oblique, oval, approximately 31% of the eye diameter, without bordering enlarged scales; infralabials 9/10; mental triangular, slightly wider than rostral, bordered laterally by first infralabials and posteriorly by two large postmentals, nine chin scales (5 left, 4 right) touching internal edge of infralabials and mental between the juncture of the second and third infralabials on each side of the head, anterior pair enlarged; dorsal scales granular, in 16 rows at midbody on dorsum (contained within one eye diameter); ventrolateral folds absent; enlarged tubercles absent; ventral scales smooth, larger than dorsal scales, in 9 rows at midbody on venter (contained within one eye diameter); femoral and precloacal pores 25, in a continuous series; cloacal spurs 2 on each side; dorsal surface of fore and hind limbs covered by granular scales; terminal two phalanges free, claws absent on first finger and on first toe, present on second to fifth digits of fore and hind feet; pads of digits II–V each with large triangular lamellae, digital formula 4-5-6-5 (forefoot) and 5-6-6-6 (hind foot); lamellae three on first finger, four on first toe; tail regenerated; dorsal caudal scales granular; subcaudals flat, slightly larger than dorsal caudal scales.

Coloration in life: Dorsal surface of head and limbs greyish brown with dark markings; dark stripe from anterior of the eye to snout distinct; dark lateral stripe on head distinct, from behind the eye to shoulder, edged above by a narrow white stripe; upper and lower lips with dark bars; dorsum greyish brown with two paravertebral stripes formed by two rows of dark spots; postsacral mark cream in U-shape and bearing anteriorly projecting arms; regenerated tail light greyish brown with dark markings; throat, venter, and precloacal region cream with small dark brown dots; testis white, unpigmented.

Coloration in preserved specimens is similar to coloration in life but with a paler venter; the orange color on tail disappeared.

Sexual dimorphism and variation.

Measurements and scalation characters of the paratypes are given in Table 1. The female differs from the males in the absence of hemipenial swellings at the tail base. The scale counts vary among the type series: scales between supranasals 2 or 3; supralabials 10 or 11; infralabials 9 or 10; chin scales 7–10; ventral scale rows 8 or 9, cloacal spurs 2 or 3 on each side in both males and female. The males have 23–25 femoral and precloacal pores (absent in the female). Ground color on upper surface of head, body, and tail is also different among individuals, varying from greyish brown to dark brown; some individuals with orange spots on dorsum and flanks. Original tail marks of orange color.

Distribution. Hemiphyllodactylus dalatensis sp. nov. is currently known only from the type locality in Da Lat Plateau, Lam Dong Province, Vietnam.

Etymology. The specific epithet dalatensis is a toponym in reference to the type locality of the species in Da Lat Plateau of the Central Highlands of Vietnam. As common names we suggest Dalat Slender Gecko (English) and Thạch sùng dẹp đà lạt (Vietnamese).

Natural history. Specimens were found on the tree, approximately 1 m above the ground near Giang Ly Ranger Station. The surrounding habitat was disturbed evergreen forest of medium hardwood and shrub ( Fig. 5 ).

Comparisons: We compared the new species from southern Vietnam with other members of the genus Hemiphyllodactylus from Vietnam and the H. aurantiacus group (see Table 2) and data obtained from the literature ( Beddome 1870; Boulenger 1903; Zug 2010; Nguyen et al. 2013, 2020; Ngo et al. 2014; Agarwal et al., 2019, 2020; Do et al. 2020).

Hemiphyllodactylus dalatensis sp. nov. differs from H. arakuensis Agarwal, Khandekar, Giri, Ramakrishnan & Karanth by having a larger size (maximum SVL 45.9 mm vs. 39 mm in H. arakuensis ), the presence of enlarged postmentals (vs. absence in H. arakuensis ), digital lamellae formula 4-5-5/6-5 (forefoot) and 5-6-6-6/5 (hind foot) (vs. 2-2-2-2 and 2/3-3-3-3, respectively, in H. arakuensis ), more precloacal and femoral pores in males (23–25 vs. 12–14 in H. arakuensis ), pore bearing precloacal and femoral scales in a continuous row (vs. separated by poreless scales in H. arakuensis ), and the presence of anteriorly projecting arms on postsacral region (vs. absence in H. arakuensis ); from H. aurantiacus Beddome by having a larger size (maximum SVL 45.9 mm vs. 37.9 mm in H. aurantiacus ), the presence of enlarged postmentals (vs. absence in H. aurantiacus ), digital lamellae formula 4-5- 5/6-5 (forefoot) and 5-6-6-6/5 (hind foot) (vs. 2-2-2-2 and 2-2-3-2/3, respectively, in H. aurantiacus ), and pore bearing precloacal and femoral scales in a continuous row (vs. separated by poreless scales in H. aurantiacus ), and the presence of anteriorly projecting arms on postsacral region (vs. absence in H. aurantiacus ); from H. banaensis Ngo, Grismer, Pham & Wood by having fewer scales between supranasals (2–3 vs. 4–11 in H. banaensis ), fewer dorsal scale rows (16 vs. 17–20 in H. banaensis ), fewer subdigital lamellae 3–4 (1FingLm) and 3–4 (1ToeLm) (vs. 5 and 5, respectively, in H. banaensis ), digital lamellae formula 5-6-6-6/5 (hind foot) (vs. 4-5-5- 5 in H. banaensis ), more precloacal and femoral pores in males (23–25 vs. 18–21 in H. banaensis ), and more cloacal spurs on each side (2–3 vs. single in H. banaensis ); from H. bonkowskii Nguyen, Do, Ngo, Pham, Pham, Le & Ziegler by having fewer dorsal scale rows (16 vs. 24–27 in H. bonkowskii ), fewer ventral scale rows (8–9 vs. 13–15 in H. bonkowskii ), digital lamellae formula 4-5-5/6-5 (forefoot) and 5-6-6-6/5 (hind foot) (vs. 3-4-4-4 and 4-5-5-5, respectively, in H. bonkowskii ), more precloacal and femoral pores in males (23–25 vs. 19 in H. bonkowskii ), and more cloacal spurs on each side (2–3 vs. single in H. bonkowskii ); from H. jnana Agarwal, Khandekar, Giri, Ramakrishnan & Karanth by having fewer ventral scale rows (8–9 vs. 11–15 in H. jnana ), digital lamellae formula 4-5-5/6-5 (forefoot) and 5-6-6-6/5 (hind foot) (vs. 2-2-2-2 and 2-2-2-2, respectively, in H. jnana ), fewer precloacal and femoral pores in males (23–25 vs. 26–28 in H. jnana ), and pore bearing precloacal and femoral scales in a continuous row (vs. separated by poreless scales in H. jnana ); from H. kolliensis Agarwal, Khandekar, Giri, Ramakrishnan & Karanth by having a larger size (maximum SVL 45.9 mm vs. 39.3 mm in H. kolliensis ), fewer ventral scale rows (8–9 vs. 10–13 in H. kolliensis ), digital lamellae formula 4-5-5/6-5 (forefoot) and 5-6-6-6/5 (hind foot) (vs. 2-2-2-2 and 2-2-2-2, respectively, in H. kolliensis ), and pore bearing precloacal and femoral scales in a continuous row (vs. separated by poreless scales in H. kolliensis ); from H. nahangensis Do, Pham, Phan, Le, Ziegler & Nguyen by having fewer scales between supranasals (2–3 vs. 4–6 in H. nahangensis ), fewer dorsal scale rows (16 vs. 18–23 in H. nahangensis ), digital lamellae formula 4-5-5/6-5 (forefoot) and 5-6-6-6/5 (hindfoot) (vs. 2/3/4-4-5-4 and 3-5-4- 4, respectively, in H. nahangensis ), and more cloacal spurs on each side (2–3 vs. single in H. nahangensis ); from H. ngocsonensis Nguyen, Do, Ngo, Pham, Pham, Le & Ziegler by having fewer dorsal scale rows (16 vs. 19–21 in H. ngocsonensis ), fewer ventral scale rows (8–9 vs. 13–15 in H. ngocsonensis ), fewer subdigital lamellae 3–4 (1ToeLm) (vs. 5–6 in H. ngocsonensis ), digital lamellae formula 4-5-5/6-5 (forefoot) and 5-6-6-6/5 (hind foot) (vs. 3-4-4-4 and 4-5-5-4, respectively, in H. ngocsonensis ), more precloacal and femoral pores in males (23–25 vs. 20 in H. ngocsonensis ), and more cloacal spurs on each side (2–3 vs. single in H. ngocsonensis ); from H. nilgiriensis Agarwal, Bauer, Pal, Srikanthan & Khandekar by having a larger size (maximum SVL 45.9 mm vs. 35 mm in H. nilgiriensis ), the presence of enlarged postmentals (vs. absence in H. nilgiriensis ), fewer ventral scale rows (8–9 vs. 12–15 in H. nilgiriensis ), digital lamellae formula 4-5-5/6-5 (forefoot) and 5-6-6-6/5 (hind foot) (vs. 2-2-2-2 and 2-2-2-2, respectively, in H. nilgiriensis ), and pore bearing precloacal and femoral scales in a continuous row (vs. separated by poreless scales in H. nilgiriensis ); from H. peninsularis Agarwal, Bauer, Pal, Srikanthan & Khandekar by having a larger size (maximum SVL 45.9 mm vs. 34 mm in H. peninsularis ), fewer chin scales (7–10 vs. 12 in H. peninsularis ), the presence of enlarged postmentals (vs. absence in H. peninsularis ), fewer dorsal scale rows (16 vs. 20 in H. peninsularis ), fewer ventral scale rows (8–9 vs. 14 in H. peninsularis ), digital lamellae formula 4-5-5/6-5 (forefoot) and 5-6-6-6/5 (hind foot) (vs. 2-2-2-2 and 2-2-2-2, respectively, in H. peninsularis ), more precloacal and femoral pores in males (23–25 vs. 17–19 in H. peninsularis ), and pore bearing precloacal and femoral scales in a continuous row (vs. separated by poreless scales in H. peninsularis ); from H. yunnanensis Boulenger by having digital lamellae formula 4-5-5/6-5 (forefoot) and 5-6-6-6/5 (hind foot) (vs. 3-3-3-3 and 3-4-4-4, respectively, in H. yunnanensis ), the presence of anteriorly projecting arms on postsacral region (vs. absence in H. yunnanensis ); the dark lateral stripe in the loreal region and on the head is more distinct in H. yunnanensis , and the presence of two paravertebral stripes formed by two rows of dark spots (vs. absence in H. yunnanensis ); from H. zugi Nguyen, Lehmann, Le, Duong, Bonkowski & Ziegler by having fewer dorsal scale rows (16 vs. 19–22 in H. zugi ), fewer ventral scale rows (8–9 vs. 14–16 in H. zugi ), digital lamellae formula 4-5-5/6-5 (forefoot) and 5-6-6-6/5 (hind foot) (vs. 3-4-4-4 and 3-4-5-5-5, respectively, in H. zugi ), more precloacal and femoral pores in males (23–25 vs. 18–21 in H. zugi ), and more cloacal spurs on each side (2–3 vs. 0–1 in H. zugi ).

Figures

FIGURE 3. The male holotype of Hemiphyllodactylus dalatensis sp. nov. (IEBR R.4830):A) Dorsal view in life, B) Precloacal region with precloacal and femoral pores in a continuous series, C) Subdigital view of right hand, and D) Subdigital view of right foot. Photos: K.V. Nguyen and Q.H. Do. Scale bar = 1 mm.

FIGURE 4. Hemiphyllodactylus dalatensis sp. nov. in life: A) male paratype (IEBR R.4831) and B) female paratype (IEBR R.4833). Photos: K.V. Nguyen.

FIGURE 5. Habitat of Hemiphyllodactylus dalatensis sp. nov. in Bidoup - Nui Ba National Park, Lam Dong Province. Photo: K.V. Nguyen.