Scincella tenuistriata, Xu & Gong & Nguyen & Deng & Bragin & Weng & Zhang & Poyarkov & Peng, 2025

Xu, Yuhao, Gong, Zhonghao, Nguyen, Tan Van, Deng, Jundong, Bragin, Andrey M., Weng, Shiyang, Zhang, Tierui, Poyarkov, Nikolay A. & Peng, Lifang, 2025, A new species of the genus Scincella Mittleman, 1950 (Squamata, Scincidae) from Guizhou Province, southwest China, ZooKeys 1258, pp. 9-33 : 9-33

Scincella tenuistriata sp. nov.

Tables 4 , 5 , Figs 4 , 5 , 6 , 7 , 8

Type material.

Holotype. • QHU R 2025009 , adult male, from Qixingguan District , Bijie City, Guizhou Province, China ( 27.2166°N, 105.0015°E; elevation ca. 1,850 m a. s. l.) collected by ZHG on April 15, 2025 . Paratypes ( n = 7). • QHU R 2025008 and QHU R 2025010 –015, seven adult males, with the same collecting information as the holotype .

Diagnosis.

Scincella tenuistriata sp. nov. can be diagnosed from other Scincella species by the following unique combination of characters: (1) medium body size in adult male, with a maximum SVL of 42.4 mm; (2) supraciliaries six; (3) supralabials seven, separated from the eye by a row of small scales; (4) infralabials six, rarely five; (5) tympanum deeply recessed and without lobules, with a tympanum diameter significantly larger than the palpebral disc (ear opening diameter / palpebral disc diameter ratio 1.84–2.25; (6) primary temporal single; (7) midbody scale rows 24; (8) ventral scale rows (excluding gulars) 40–43, gulars 21–23, with total ventral + gular scale rows numbering 61–66; (9) toes nearly or just touching fingers when limbs are adpressed; (10) 9 or 10 enlarged lamellae beneath finger IV, and 11 or 12 beneath toe IV; (11) the dark dorsolateral stripes narrow and wavy, covering 0.5–1 scale rows on the trunk, with four scale rows in between on the dorsum; (12) dorsal surface of body brassy, scattered with small dark sports; (13) in life, the ventral surface of the trunk is yellow, scattered with irregular dark spots.

Description of the holotype.

Adult male in a good state of preservation with size medium, ( SVL 40.3 mm); tail relatively long ( TAL 63.7 mm, TAL / SVL ratio 1.58). Axilla-groin distance 22.2 mm, AGD / SVL ratio 0.55. Head elongated, indistinct from the neck ( HL 8.41 mm, HW 4.75 mm, HH 3.11 mm). Snout short, obtuse, round anteriorly ( ESD 2.31 mm, EN 2.00 mm). Eye large ( ED 2.13 mm), lower eyelid with an undivided transparent palpebral disc (window), PDD 0.80 mm. Ear nearly circular; tympanum recessed and distinctly larger than the palpebral disc ( EL 1.47 mm, EL / PDD ratio 1.84). Limbs relatively short, toes nearly touching fingers when limbs are adpressed ( FLL 9.78 mm, HLL 11.77 mm, F 4 L 2.11 mm, T 4 L 3.88 mm, FLL / SVL ratio 0.24, HLL / SVL ratio 0.29). Digits moderately long and slender, each ending in a clearly visible, slightly curved claw. Relative digit lengths of the manus: IV > III > II > V > I, and of the pes: IV > III > V > II > I.

Head scalation (Fig. 4 ). Head scales smooth. Rrostral convex, wider than high, distinctly visible from above, in contact with the 1 st supralabials, nasals, and frontonasal; supranasals absent; frontonasal one, approximately boat-shaped, width ~ 2 × the height., in contact with the rostral, nasals, anterior loreals, prefrontals and frontal; prefrontals two, not in contact with each other, separated medially by frontal; frontal slender, longer than wide, diamond-shaped, in contact with the 1 st superciliary, 1 st and 2 nd supraoculars laterally; a pair of frontoparietals, in contact with each other anteriorly, bordered by frontal, 2 nd to 4 th supraoculars, interparietal and parietals; interparietal diamond-shaped, width less than height; parietals large, in contact posteriorly, posterolateral border surrounded by the upper secondary temporals, prenuchals, and enlarged nuchals; a single pair of prenuchals, and three pairs of enlarged nuchals.

Nostril oval, located at the center of the nasal; nasal entire, diamond-shaped, width approximately equal to height, in contact with the rostral, frontonasal, 1 st loreal, and 1 st supralabial; loreals 2, subequal in size; supraoculars 4 / 4, the 1 st contacts the frontal, the 2 nd is the largest and contacts both the frontal and frontoparietals, and the 3 rd and 4 th contact the frontoparietals; superciliaries 6 / 6, the 1 st is the largest; the palpebral disc is bordered by a series of small scales; temporals 1 + 2, the anterior one subrectangular, the upper secondary temporal is the largest, while the lower one is smaller and broadly contacts the upper; supralabials 7 / 7, 1 st smallest, 5 th below the window, 6 th largest.

Mental wider than long, round anteriorly, in contact with the 1 st infralabials and postmental; postmental large and subpentagonal, contacting the mental, the first two infralabials on each side, and the first pair of chin shields; infralabials 5 / 6, 1 st smallest, 4 th / 6 th largest; three pairs of chin shields, the first pair in contact medially, the second pair separated by one gular scale, and the third pair separated by three gulars; gulars 22.

Body scalation (Fig. 5 ). Body scalation smooth, scales around midbody in 24 rows; distinctly larger than lateral scales and slightly larger than ventrals; paravertebral scale series composed of 51 scales; dorsal scales between dorsolateral stripes 1 / 2 + 4 + 1 / 2. Ventral scales slightly enlarged medially, decreasing toward the flanks; ventral scale rows (excluding gulars) 41, GS + VS 63; medial pair of precloacal scales enlarged, the left one overlapping the right one. Tail complete; tail scales imbricate and generally uniform in shape, except for the markedly widened subcaudals. Limbs pentadactyl; dorsal surface of fingers and toes covered with two interdigitating scale rows; 10 enlarged lamellae beneath finger IV and 11 beneath toe IV.

Coloration of the holotype in life (Fig. 6 ). In life, dorsal surface of the head is brassy, scattered with small, irregular dark spots. The upper lateral margins of the head also copper-colored, gradually fading to light brown ventrally, and densely covered with small, ink splatter-like dark spots. The ventral surface of head is creamy white, marked with irregular dark blotches. Each blotch is smaller than a single scale and composed of clusters of over a dozen minute dots.

The dorsal surface of the body and tail is brassy, scattered with small, irregular dark spots. A dark dorsolateral stripe is slightly wavy and very narrow, covering ~ 0.5–1 scale row on the trunk. The stripe originates at the snout, follows the upper edges of the nasal and loreals, is interrupted at the eye, then resumes posterior the eye and extends along the flanks above the forelimbs and hindlimbs, reaching the tip of the tail. The ground color of the upper flanks is dark brown, bearing scattered black spots that occasionally coalesce into broken, irregular longitudinal streaks. Further ventrally, the brown gradually fades, with the surface marked by small cream and blackish-brown speckles. Near the ventral edge, the brown coloration breaks up further and merges gradually into the lighter ventral coloration. The ventral surface of the trunk is yellow, with a few small, irregular dark spots. The ventral surface of the tail is yellow basally, transitioning to gray posteriorly and densely covered with small dark spots throughout.

Coloration of the holotype in preservation (Fig. 7 ). After one month in ethanol, the coloration remains similar to that in life, except that the lateral body appears paler, the ventral surface of the trunk faded to a very light cream yellow, and the ventral surface of the tail has turned grayish white.

Variation.

Morphometric and meristic data of the type series of Scincella tenuistriata sp. nov. are provided in Table 4 . The paratypes exhibit coloration generally similar to the holotype, with minor individual variation. Notably, QHU R 2025010 has an almost spotless ventral surface at midbody, whereas QHU R 2025011 , QHU R 2025012 , and QHU R 2025013 bear numerous large, dark spots scattered across the venter (Fig. 8 ). The main differences in morphometric and scalation characters among the type series ( n = 8) are as follows: TAL / SVL ratio 1.58–1.75; toes can touch the fingers when limbs are adpressed in specimens QHU R 2025010 , QHU R 2025014 , and QHU R 2025015 ; PVSR 51–61; VS 40–43; GS 21–23, GS + VS 61–65; prefrontals in contact in specimens QHU R 2025012 , QHU R 2025013 , QHU R 2025014 , and QHU R 2025015 ; NU 3–4; and F 4 S 9–10, T 4 S 11–12.

Distribution and natural history notes.

To date, Scincella tenuistriata sp. nov. is currently known only from its type locality. All specimens were collected in April 2025 at elevations ranging from 1,850 m a. s. l., under leaf litter and beneath rocks along a shaded mountain trail. The surrounding habitat is characterized by well-preserved forest dominated by coniferous tree species, with some broad-leaved trees mixed in, indicative of a cool, moist montane environment. (Fig. 9 ).

During the survey, daytime temperatures averaged ~ 24 ° C, dropping to ~ 15 ° C at night. The skinks were noticeably more active during daylight hours, particularly in the morning and late afternoon, when they were frequently observed actively moving across the forest floor. At night, individuals retreated beneath cover objects and could only be located through careful searching. Fecal analysis revealed small beetle elytra and partially digested crickets, indicating a diet primarily composed of small, non-venomous arthropods, particularly insects.

Comparisons.

Based on both morphological and molecular evidence, Scincella tenuistriata sp. nov. is closely related to S. alia , S. chengduensis , S. devorator (Darevsky, Orlov & Cuc) , S. fansipanensis , S. liangshanensis , S. monticola , S. potanini , S. qianica and S. truongi Pham, Ziegler, Pham, Hoang, Ngo & Le. Detailed morphological comparisons between Scincella tenuistriata sp. nov. and its closely related congeners are shown in Table 5 .

Scincella tenuistriata sp. nov. can be distinguished from S. alia by MBSR 24 (vs 26–28); VS 40–43 (vs 44–52); GS + VS 61–66 (vs 66–76); and by the presence of dark spots on the middle of the ventral surface (vs absence). It can be distinguished from S. chengduensis by EL / PDD 1.84–2.25 (vs 1.05–1.58); F 4 S 9–10 (vs 8–9); MBSR 24 (vs 23); and dorsolateral stripes being narrow and wavy, covering ~ 0.5–1 scale rows on the trunk (vs stripes with relatively straight upper margins, covering ~ 1–2.5 scale rows). It can be distinguished from S. devorator by MBSR 24 (vs 30); SCI 6 (vs 8); T 4 S 11–12 (vs 17); and PVSR 51–61 (vs 68). It can be distinguished from S. fansipanensis by smaller body size, SVL 37.6–42.4 mm (vs 43.5–59.0 mm); F 4 S 9–10 (vs 7–9); PVSR 51–61 (vs 60–68); and presence of dark spots on the ventral surface (vs absence). It can be distinguished from S. liangshanensis by smaller body size, SVL 37.6–42.4 mm (vs 43.1–61.9 mm); EL / PDD ratio 1.84–2.25 (vs 0.14–0.22); PVSR 51–61 (vs 69–80); VS 40–43 (vs 43–57); dorsolateral stripes being narrow and wavy, covering ~ 0.5–1 scale rows on the trunk (vs stripes with relatively straight upper margins, covering ~ 1.5–2.5 scale rows); and presence of dark spots on the ventral surface (vs absence). It can be distinguished from S. monticola by PVSR 51–61 (vs 62–80); VS 40–43 (vs 45–52); (3) GS + VS 61–66 (vs 67–77); FLL / SVL 0.22–0.26 (vs 0.13–0.19); HLL / SVL 0.29–0.35 (vs 0.20–0.22); EL / PDD 1.84–2.25 (vs 0.62–1.11); dorsolateral stripes being narrow and wavy, covering ~ 0.5–1 scale rows on the trunk (vs stripes with relatively straight upper margins, covering ~ 1.5–2 scale rows); and presence of dark spots on ventral surface (vs absence). It can be distinguished from S. potanini by a comparatively longer tail, TAL / SVL ratio 1.58–1.75 (vs 1.02–1.12); a greater EL / PDD ratio (1.84–2.25 vs 0.79–1.25); PVSR 51–61 (vs 69–73); the dorsolateral stripes narrow and wavy, covering ~ 0.5–1 scale rows on the trunk (vs stripes with relatively straight upper margins, covering ~ 1.5–3 scale rows); and presence of dark spots on the ventral surface (vs absence). It can be distinguished from S. qianica by MBSR 24 (vs. 26); PVSR 51–61 (vs. 61–66); VS 40–43 (vs. 46–53); GS + VS 61–66 (vs. 66–75); and T 4 S 11–12 (vs. 13–14) Furthermore, it can be distinguished from S. truongi by smaller body size, SVL 37.6–42.4 mm (vs 49.0– 59.4 mm); MBSR 24 (vs 28); TEMP 1 + 2 (vs 2 + 2); EL / PDD ratio 1.84–2.25 (vs 1.33–1.52); and presence of dark spots on the ventral surface (vs absence).

Among the other three Chinese congeners (including S. tsinlingensis , S. huanrenensis , and S. schmidti ) that share the character of having four dorsal scale rows between the dorsolateral stripes, Scincella tenuistriata sp. nov. can be distinguished from S. tsinlingensis by MBSR 24 (vs 26–28); PVSR 51–61 (vs. 70–90); GS + VS 61–66 (vs 83–98); EL / PDD ratio 1.84–2.25 (vs 0.80–1.14); and TAL / SVL ratio 1.58–1.75 (vs 1.24–1.42). It can be distinguished from S. huanrenensis by having MBSR 24 (vs 25–28); PVSR 51–61 (vs 66–79); T 4 S 11–12 (vs 13–16); EL / PDD ratio 1.84–2.25 vs (0.61–1.14); and TAL / SVL ratio 1.58–1.75 (vs 1.19–1.47). And it can be distinguished from S. schmidti by having MBSR 24 (vs 26); PVSR 51–61 (vs 68–91); GS + VS 61–66 (vs 71–87); and TAL / SVL ratio 1.58–1.75 (vs 1.9). In comparison with the remaining congeners in China, Scincella tenuistriata sp. nov. can be easily distinguished from S. barbouri , S. doriae , S. formosensis , S. modesta , S. przewalskii , S. reevesii , and S. wangyuezhaoi by having four dorsal scale rows between the dorsolateral stripes (vs 6–8). Moreover, it can be distinguished from S. barbouri by having T 4 S 11–12 (vs 15–17); from S. doriae by having MBSR 24 (vs 30–32), T 4 S 11–12 (vs 15–18); from S. formosensis by having MBSR 24 (vs 28–29), and T 4 S 11–12 (vs 14–18); from S. modesta by having TAL / SVL ratio 1.58–1.78 (vs 1.2–1.4), MBSR 24 (vs 26–28), and T 4 S 11–12 (vs 13–15); from S. przewalskii by having SO 4 (vs 3) and T 4 S 11–12 (vs 17); from S. reevesii by having T 4 S 11–12 (vs 15–18); and from S. wangyuezhaoi by having MBSR 24 (vs 27–30), and VS 40–43 (vs 46–59).

In addition, Scincella tenuistriata sp. nov. can be easily distinguished from other Asian congeners as follows: from S. apraefrontalis Nguyen, Nguyen, Böhme & Ziegler , S. auranticaudata Nguyen, Nguyen, Le, Nguyen, Phan, Vo, Murphy & Che , S. badenensis Nguyen, Nguyen, Nguyen & Murphy , S. balluca Bragin, Zenin, Le, Nguyen, Nguyen & Poyarkov , S. baraensis Nguyen, Nguyen, Nguyen & Murphy , S. boettgeri , S. capitanea Ouboter , S. darevskii Nguyen, Ananjeva, Orlov, Rybaltovsky & Böhme , S. dunan , S. honbaensis Nguyen, Nguyen, Le, Nguyen, Phan, Vo, Murphy & Che , S. melanosticta , S. nigrofasciata Neang, Chan & Poyarkov , S. ochracea , S. ouboteri Pham, Pham, Le, Ngo, Ziegler & Nguyen , S. rara , S. rufocaudata (Darevsky & Nguyen) , S. rupicola (Smith) , S. truongi Pham, Ziegler, Pham, Hoang, Ngo & Le , S. vandenburghi (Schmidt) , and S. victoriana (Shreve) by having 24 MBSR (vs 18 in S. apraefrontalis , 34–36 in S. auranticaudata , 30–32 in S. balluca , 32–36 in S. badenensis , 30 in S. baraensis , 26–32 in S. boettgeri , 30–32 in S. capitanea , 28 in S. darevskii , 26–29 in S. dunan , 28 in S. honbaensis , 30–32 in S. melanosticta , 32–33 in S. nigrofasciata , 30–32 in S. ochracea , 30–32 in S. ouboteri , 24 in S. rara , 30–34 in S. rufocaudata , 33–36 in S. rupicola , 28–30 in S. vandenburghi , and 26 in S. victoriana ); and from S. punctatolineata Boulenger by nuchals present (vs absent) and T 4 S 11–12 (vs 13–15).

Etymology.

The specific name tenuistriata is a Latin adjective in the nominative singular (adjusted to the feminine gender of the genus name), derived from the Latin words tenuis (meaning narrow) and stria (meaning furrow, channel; striatus meaning striped). The name is given in reference to the narrow, dark dorsolateral stripes of the new species. We propose the following common names for this species: 细纹滑蜥 (Xì Wén Huá Xī) in Chinese, “Narrow-striped Ground Skink” in English, and “Tonkopolosyi malyi stsink” (Тонкополосый малый сцинк) in Russian.

Figures

Figure 4. Head scalation of Scincella tenuistriata sp. nov. (holotype, QHU R 2025009, adult male). A. Dorsal; B. Lateral; C. Ventral views. Notes: CH: chin-shield; F: frontal, FrN: frontonasal; FrP: frontoparietal; IL: infralabials; IP: interparietal; L: loreals; M: mental; NU: nuchals; P: parietal; PF: prefrontal; PM: postmental; R: rostral; SCI: supraciliaries; SL: supralabials; SO: supraoculars; TEM: temporals. Photographs and drawings by YHX. Scale bars: 5 mm.

Figure 5. Dorsal (A), lateral (B), and ventral (C) views of the body; D. Ventral view of the hand; E. Ventral view of the foot of Scincella tenuistriata sp. nov. (holotype, QHU R 2025009, adult male) in preservation. Photographs by YHX. Scale bars: 5 mm (A – C); 2 mm (D, E).

Figure 6. Dorsal (A) and ventral (B) views of the holotype (QHU R 2025009, adult male) of Scincella tenuistriata sp. nov. in life in situ. Photographs by YHX.

Figure 7. Dorsal (A) and ventral (B) views of the holotype (QHU R 2025009, adult male) of Scincella tenuistriata sp. nov. in preservation. Photographs by YHX. Scale bars: 10 mm.

Figure 8. Coloration of paratypes of Scincella tenuistriata sp. nov. in preservation. A. QHU R 2025010, adult male; B. QHU R 2025011, adult male; C. QHU R 2025012, adult male. Photographs by YHX. Scale bars: 10 mm.

Figure 9. Habitat of Scincella tenuistriata sp. nov. in Qixingguan District, Bijie City, Guizhou Province, China.