Scincella ouboteri, Pham & Pham & Le & Ngoc & Ziegler & Nguyen, 2024

Pham, Anh Van, Pham, Cuong The, Le, Minh Duc, Ngoc, Hai Ngo, Ziegler, Thomas & Nguyen, Truong Quang, 2024, A new skink of the genus Scincella Mittleman, 1950 (Squamata: Scincidae) from Hoa Binh Province, northern Vietnam, Zootaxa 5428 (1), pp. 91-106 : 96-102

Scincella ouboteri sp. nov.

( Figs. 3 , 4 )

Holotype. IEBR R.5042 (Field number HB 2014.166), adult male, collected on 8 October 2014 by T. Q. Nguyen, C. T. Pham, M.D. Le, and H.N. Ngo in karst forest near Cho Village (20 o 25.457’N, 105 o 19.096’E, at an elevation of 409 m a.s.l.), Tu Do Commune , within Ngoc Son– Ngo Luong Nature Reserve, Lac Son District, Hoa Binh Province, Vietnam.

Paratypes. IEBR R.5043 (Field number HB 2014.165), adult male, IEBR R.5044 (HB 2014.167), adult male, IEBR R.5045 (HB 2014.173), adult male, IEBR R.5046 (HB 2014.178), adult male, IEBR R.5047 (HB 2014.168), adult female, IEBR R.5048 (HB 2014.174), adult female, IEBR R.5049 (HB 2014.175), adult female, IEBR R.5050 (HB 2014.176), adult female, and IEBR R.5051 (HB 2014.177), adult female, bear the same data as the holotype.

Diagnosis. The new species can be distinguished from other species of Scincella by a combination of the following characteristics: size medium (SVL up to 58.6 mm); primary temporals 2; external ear opening present, with 3 or 4 lobules on anterior margin; loreals 2; supralabials 7; infralabials 6 or 7; nuchals in 2–4 pairs; midbody scales in 30–32 rows; dorsal scales smooth, in 6 rows across the back; paravertebral scales 65–73, not widened; ventral scales in 65–71 rows; 10–12 smooth lamellae beneath finger IV and 18–20 beneath toe IV; toes overlapping fingers when limbs adpressed along body; dorsal surface of body and tail bronze brown with a black vertebral stripe, in width of two dorsal scales, two bright dorsolateral stripes from behind the head to middle of tail, a dark stripe running from nostril to eye and extending from posterior corner of eye along upper part of flank and tail.

Description of holotype. Size medium (SVL 43.5 mm, TaL 74.2 mm, SVL/TaL 0.58); head longer than wide (HL 8.35 mm, HW 6.17 mm, SVL/HL 5.21); snout obtuse, round anteriorly; rostral wider than high, distinctly visible from above; supranasals absent; frontonasal wider than long, in contact with rostral, nasals, anterior loreals, and frontal; prefrontals not in contact with each other; frontal narrowing posteriorly, about 1.1 times longer than the distance to the tip of snout, in contact with prefrontals, first and second supraoculars, and frontoparietals; frontoparietals in contact with each other anteriorly, bordered by frontal, three supraoculars, parietals, and interparietal; interparietal lozengeshaped with indistinct transparent spot posteriorly; parietals in contact posteriorly, posterolateral border surrounded by three scales on each side; nuchal scales in two pairs; nostril in center of nasal, in contact with rostral, frontonasal, loreal, first supralabial; loreals 2, anterior loreal higher but narrower than posterior one; preocular 1; presuboculars 2, in contact with lower preocular, third and fourth supralabials; supraciliaries 7; supraoculars 4, the first longest, the second widest, fourth supraocular followed by a small postsupraocular; postoculars 3, anterior one in contact with seventh supraciliary, postsupraocular, and upper postsubocular; postsuboculars 2, lower one in contact with sixth supralabial; primary temporals 2, lower one in contact with sixth and seventh supralabials; secondary temporals 2, upper very large, in contact with posterolateral, border of parietal, overlapped by lower one; lower eyelid with an undivided opaque window (central disc), separated from supralabials by 3 rows of granular scales; supralabials 7, fifth below the eye; external ear opening present, anterior margin with 4 distinct lobules, tympanum deeply sunk; mental wider than long, round anteriorly, in contact with anterior infralabials and postmental; infralabials 6, first small; postmental undivided, in contact with mental, first and anterior portion of second infralabials on each side, and first pair of chinshields; chinshields in 3 pairs, first pair in contact with each other medially, second pair separated from each other by a gular scale, and third pair separated from each other by 3 scales; midbody scales in 32 rows; dorsal scales smooth, in 6 rows across the back; paravertebral scales 65, not widened; ventral scales smooth, in 66 rows; precloacals 4, inner scales overlapping outer ones, central two enlarged, left one overlapped by right one; tail thick at base, medial subcaudals widened vertical length of tail. Limbs relatively developed (SVL/FlL 3.77, SVL/HlL 2.67), pentadactyl, dorsal surface of digits covered by two scale rows on basal and by a single row on terminal phalanges; subdigital lamellae keeled, in one row under the digits, 10 under fourth finger and 18 under fourth toe; toes and fingers overlapping when adpressed along body, adpressed forelimb reaching to eye ( Fig. 4 , Table 3 ).

Coloration in life. Dorsal surface of body and tail bronze brown with a black vertebral stripe, in width of two dorsal scales, extending from nuchal region to tail base, discontinuous posteriorly; two bright dorsolateral stripes from behind the head to middle of tail; a dark stripe running from nostril to eye and extending from posterior margin of eye along upper part of flank and tail; lateral side of the head and flank with white spots; lower part of flank and tail base reddish brown; chin, throat and venter cream, outer edge of ventral scales dark grey, forming a network; underside of fore and hind limbs brown; ventral surface of tail greyish cream ( Figs. 3 , 4 ).

Variation. Prefrontals are in contact with each other in seven paratypes ( IEBR R.5043–5049). The paratype IEBR R . 5047 has an external ear opening with three auricular lobules. The paratype IEBR R . 5046 has 30 midbody scale rows. Nuchal scales in 3 pairs in four paratypes ( IEBR R.5044, 5047–5049), 3/ 2 in two paratypes ( IEBR R.5043, 5046), and 4 pairs in one paratype ( IEBR R.5045) .

Distribution. Scincella ouboteri sp. nov. is currently known only from the type locality in Hoa Binh Province, Vietnam ( Fig. 1 ).

Natural history. The skinks were found in leaf litter on the ground of karst forest between 18:40 and 22:00. The surrounding habitat was limestone karst forest with large, medium and small hardwoods mixed with shrubs and vines ( Fig. 5 ). Air temperatures at the sites ranged from 20.5–28.5 oC and relative humidity was 60–80%. Other reptile species found at the sites included Acanthosaura lepidogaster (Cuvier) and Gekko cf. palmatus Boulenger.

Etymology. We name the new species in honor of Dr. Paul E. Ouboter, Institute for Neotropical Wildlife and Environmental Studies ( Suriname), who provided the first comprehensive taxonomic revision of the genus Scincella of Asia. As common names, we suggest Ouboter’s Smooth Skink (English) and Thằn lằn cổ ouboter (Vietnamese).

Comparisons. We compared the new species with other known taxa in the genus Scincella from Asia based on examination of specimens (see Appendix) and data obtained from the literature.

Morphologically, the new species resembles Scincella ochracea , another species known from northern Vietnam. However, they are distinguished from each other by having a larger size in the new species (males with maximum SVL 52.43 mm, mean ± SD 46.9 ± 4.3 mm, n = 5 vs. 45.4 mm, mean ± SD 44.0 ± 1.42 mm, n = 7 and females with maximum SVL 58.56 mm, mean ± SD 49.9± 6.6 mm, n = 5 vs. 51.0 mm, mean ± SD 46.7± 2.88 mm, n = 8); more lamellae beneath toe IV (18–20 vs. 15–17); and different dorsal color pattern (dorsum with a black vertebral stripe, in width of two dorsal scales vs. a discontinuous stripe, in width of one-third dorsal scales).

Scincella ouboteri sp. nov. has two primary temporals and thus differs from the following species in the genus Scincella : S. apraefrontalis , S. baraensis , S. darevskii , S. devorator , S. melanosticta , S. monticola , S. punctatolineata (Boulenger) , and S. rara , which have only one primary temporal. The new species has toes overlapping fingers when limbs adpressed along body, that differs from the following species, where toes and fingers do not overlap: S. apraefrontalis , S. darevskii , S. devorator , S. huanrenensis Zhao & Huang , S. monticola , S. nigrofasciata Neang, Chan & Poyarkov , S. potanini (Günther) , S. punctatolineata , and S. rara . In addition, the new species has 3 or 4 lobules on external ear opening and thus differs from the following taxa (external ear opening without lobules): S. apraefrontalis , S. badenensis , S. baraensis , S. barbouri (Stejneger) , S. boettgeri (van Denburgh) , S. capitanea Ouboter , S. devorator , S. doriae , S. formosensis (van Denburgh) , S. macrotis (Steindachner) , S. melanosticta , S. modesta (Günther) , S. monticola , S. nigrofasciata , S. potanini , S. rufocaudata , S. rupicola , S. schmidti (Barbour) , and S. tsinlingensis (Hu & Zhao) .

The new species differs from S. apraefrontalis by having more midbody scale rows (30–32 vs. 18), more paravertebral scales (65–73 vs. 52), more ventral scales (65–71 vs. 50), dorsal scales not enlarged (vs. distinctly enlarged), more lamellae beneath toe IV (18–20 vs. 8–9), and the presence of prefrontal (vs. absent); from S. baraensis by having fewer dorsal scale rows on back (6 vs. 8), and different dorsal color pattern (dorsum with a wide black vertebral stripe vs. with black dots); from S. badenensis by having more nuchal pairs (2–4 vs. 0–1); from S. barbouri by having more midbody scale rows (30–32 vs. 26–28) and more lamellae beneath toe IV (18–20 vs. 15–17); from S. boettgeri by having more lamellae beneath toe IV (18–20 vs. 15–16); from S. capitanea by having different dorsal color pattern (dorsum with a wide black vertebral stripe vs. with small black spots); from S. darevskii by having more paravertebral scale (65–73 vs. 62), more lamellae beneath toe IV (18–20 vs. 17), and fewer supraoculars (4 vs. 5); from S. devorator by having more midbody scale rows (30–32 vs. 28); from S. doriae by having different dorsal color pattern (dorsum with a wide black vertebral stripe vs. with brown spots); from S. huanrenensis by having more midbody scale rows (30–32 vs. 26–28), more lamellae beneath toe IV (18–20 vs. 13–16), and fewer ventral scales (65–71 vs. 75–89); from S. melanosticta by the presence of nuchal scales (2–4 pairs vs. absent), fewer midbody scale rows (30–32 vs. 34–38), fewer dorsal scale rows on back (6 vs. 10), and different dorsal color pattern (dorsum with a wide black vertebral stripe vs. with irregular dark spots); from S. modesta by having more lamellae beneath toe IV (18–20 vs. 10–15) and different dorsal color pattern (dorsum with a wide black vertebral stripe vs. with black spots); from S. monticola by having more midbody scale rows (30–32 vs. 22–26), more lamellae beneath toe IV (18–20 vs. 10–13), more paravertebral scales (65–73 vs. 52–59), and more ventral scales (65–71 vs. 52–58); from S. nigrofasciata by having more nuchal scales (2–4 pairs vs. 0 or 1 pair), fewer dorsal scale rows on back (6 vs. 8), and different dorsal color pattern (dorsum with a wide black vertebral stripe vs. with 5–7 discontinuous stripes); from S. potanini by having more midbody scale rows (30–32 vs. 27) and more lamellae beneath toe IV (18–20 vs. 17); from S. przewalskii (Bedriaga) by having more supralabials (7 vs. 6) and more lamellae beneath toe IV (18–20 vs. 17); from S. punctatolineata by having more midbody scale rows (30–32 vs. 24–26) and more lamellae beneath toe IV (18–20 vs. 13–15; from S. rara by having more midbody scale rows (30–32 vs. 24), more paravertebral scales (65–73 vs. 53), and a single row of lamellae beneath toes II–IV (vs. double rows); from S. reevesii by having more nuchals scales (2–4 pairs vs. 0 or 1) and fewer dorsal scale rows on back (6 vs. 8); from S. rufocaudata by the presence of nuchal scales (2–4 pair vs. absent), fewer dorsal scale rows on back (6 vs. 10), and more lamellae beneath toe IV (18–20 vs. 15); from S. rupicola by having fewer midbody scale rows (30–32 vs. 34–36), fewer dorsal scale rows on back (6 vs. 8); and the presence of nuchals scales (2–4 pairs vs. 0 or 1); from S. schmidti by having more midbody scale rows (30–32 vs. 26) and more lamellae beneath toe IV (18–20 vs. 11); from S. tsinlingensis by having more lamellae beneath toe IV (18–20 vs. 11–16); from S. vandenburghi (Schmidt) by having more midbody scale rows (30–32 vs. 28) and more lamellae beneath toe IV(18–20 vs. 12); and from S. victoriana (Shreve) by having more midbody scale rows (30–32 vs. 26), dorsal scales smooth (vs. keeled), and more lamellae beneath toe IV (18–20 vs. 15).

Figures

FIGURE 1. Map showing the type locality of Scincella ouboteri sp. nov. in Hoa Binh Province, Vietnam (black circle).

FIGURE 3. Holotype of Scincella ouboteri sp. nov. (IEBR 5042) in life: A) Dorsal view and B) Ventral view. Photos: T.Q. Nguyen.

FIGURE 4. Holotype of Scincella ouboteri sp. nov. (IEBR 5042) in preservative: Head: A) Lateral view, B) Dorsal view, C) Ventral view; D) Ventral view of toes and E) Ventral view of fingers. Photos: A.V. Pham.

FIGURE 5. Habitat of Scincella ouboteri sp. nov. in Ngoc Son–Ngo Luong Nature Reserve, Hoa Binh Province, Vietnam. Photos: T.Q. Nguyen.