Scincella alia, Bragin & Zenin & Dang & Dinh & Nguyen & Poyarkov, 2025

Bragin, Andrey M., Zenin, Evgeniy S., Dang, Cuong Hung, Dinh, Tu Vu Anh, Nguyen, Tan Van & Poyarkov, Nikolay A., 2025, A new mountain species of the genus Scincella Mittleman, 1950 (Squamata: Scincidae) from Ha Giang Province, northern Vietnam, Zootaxa 5636 (2), pp. 201-236 : 212-229

Scincella alia sp. nov. Bragin, Zenin, Nguyen & Poyarkov

http://zoobank.org/ urn:lsid:zoobank.org:act:E6A4DBCD-E2C8-474F-8C64-F93B39956936

( Figures 3–6 ; Table 3)

Holotype. ZMMU Re-18147 (field no. NAP-15700) ( Figs. 3–6 ), adult male, from Chieu Lau Thi (also Kieu Lieu Ti) Mountain within Tay Con Linh range in Ho Thau Commune, Hoang Su Phi District, Ha Giang Province, northeastern Vietnam (22.65997°N, 104.60969°E; elevation 2094 m asl.) collected by A. M. Bragin on March 14, 2024.

Paratypes (n=8). Eight individuals were collected from the same locality as the holotype, including four adult males VRTC NAP15694 (field no. NAP-15694), VRTC NAP15699 (field no. NAP-15699), ZMMU Re-18150 (field no. NAP-15701) and VRTC NAP15702 (field no. NAP-15702); and four adult females ZMMU Re-18148 (field no. NAP-15695), VRTC NAP15696 (field no. NAP-15696), ZMMU Re-18149 (field no. NAP-15697), and VRTC NAP15698 (field no. NAP-15698) .

Referred materials (n=6). Six individuals, including adult male VRTC NAP14089 (field no. NAP-14089); two adult females VRTC NAP14081 (field no. NAP-14081) and VRTC NAP14092 (field no. NAP-14092); and three subadult individuals VRTC NAP14084 (field no. NAP-14084), VRTC NAP14085 (field no. NAP-14085), and VRTC NAP14087 (field no. NAP-14087) from Tay Con Linh Mountain within Tay Con Linh Range in Cao Bo Commune, Vi Xuyen District, Ha Giang Province of northeastern Vietnam (22.80169°N, 104.8068°E; elevation 2369 m asl.)

collected by A. M. Bragin and N. A. Poyarkov on April 20–24, 2023. Six individuals, including adult male ZMMU Re-18154 (field no. NAP-14090); three adult females ZMMU Re-18153 (field no. NAP-14088), ZMMU Re-18155 (field no. NAP-14091), and ZMMU Re-18156 (field no. NAP-14093); and two subadult individuals ZMMU Re- 18151 (field no. NAP-14082) and ZMMU Re-18152 (field no. NAP-14083) from Tay Con Linh Mountain within Tay Con Linh Range in Cao Bo Commune, Vi Xuyen District, Ha Giang Province of northeastern Vietnam (22.80169°N, 104.8068°E; elevation 2369 m asl.) collected by A. M. Bragin and N. A. Poyarkov on April 20–24, 2023.

Etymology. The specific epithet of the new species is formed from the Latin adjective “ alius ” ( “ alia ” in feminine gender), meaning “another” or rather “different one.” This name is given in reference to the fact that this species represents yet another representative of the Scincella potanini - monticola complex, which all are morphologically quite similar to each other. We propose the following common names for this species: “ Tay Con Linh Ground Skink ” in English, “ Thằn lằn cổ Tây Côn Lĩnh ” in Vietnamese, and “ Teikonlinskiy malyi stsink ” (« ТэйкОнЛиньский мАЛЫй сцинк ») in Russian.

Diagnosis. Scincella alia sp. nov. can be easily distinguished from all other congeners by the following unique combination of morphological features: (1) slender, medium-sized body, snout-vent length 38.2–48.2 mm; (2) prefrontals separated from each other; (3) infralabials seven; (4) supraciliaries six; (5) two preoculars, three presuboculars, two postoculars, three postsuboculars; (6) supralabials separated from the eye by a row of small scales; (7) tympanum deeply recessed without lobules; (8) midbody scale rows 26 (rarely 28); (9) dorsal scales smooth, slightly enlarged, with 56–63 paravertebral scale rows, 66–76 ventral scale rows (including gulars); (10) upper edge of the lateral longitudinal stripes relatively straight, with four rows of dorsal scales in the middle; (11) enlarged, undivided lamellae beneath finger IV 7–10; (12) enlarged, undivided lamellae beneath toe IV 11–13; (13) ventral surface of head and belly lacking black spots, ventral surface of tail ornamented with dark spots; (14) dorsal surface of body grayish brown with small dark and pale spots; (15) ventral surface of throat, belly, and base of tail ranging from cream yellow in females to lemon yellow in males.

Description of the holotype ( Figs. 3–6 ). Adult male in a good state of preservation with 20 mm long midventral incision; hemipenes fully everted to determine sex and for description; specimen preserved in linear manner; tail curved to right (SVL 46.1 mm; TaL 84.8 mm; total length 130.9 mm); snout rounded and acute in dorsal and lateral aspects (EED/END 1.88); nostril with lateral orientation, slightly oval, posterior edge oriented diagonally upward, situated much closer to the snout tip than to the eye (END/SNL 0.71); head robust, longer than wide (HL2/HW 1.2). Body slender (MBW/SVL 0.15); head widened posteriorly; border between head and neck clearly visible. Forelimbs and hindlimbs relatively short and stout (FLL/SVL 0.22; HLL/SVL 0.28), normally developed, each with five digits; tips of digits of adpressed forelimbs and hindlimbs do not meet; adpressed forelimbs do not reach eye; forearm very short (ForL/SVL ratio 0.09) 4.3 mm; tibia shorter than forearm (TBL/ForL 0.7), and than femur (TBL 3.4 mm, FML 5.1 mm; TBL/SVL 0.07; TBL/FML ratio 0.66); digits moderately long, slender, ending with distinctly visible, sharp, thin, slightly curved and pointed claws ( Figs. 4 , 5 A, B ). Subdigital lamellae smooth on manus and pes, entire; number of subdigital lamellae (without taking into account claw sheaths): on right manus 4-6-9-10-6; on right pes 5-8-10-12-10. Relative lengths of digits: left manus IV> III> V> II> I; left pes IV> III> V> II> I. Scales on dorsal and ventral surfaces of limbs smooth and imbricate; femoral scales large with longitudinal orientation. Scales on palmar and plantar regions much smaller than the associated digital lamellae and scales on ventral surfaces of limbs; rounded, smooth, slightly convex ( Fig. 4 D, E ). Other measurements and ratios are given in Table 3.

Rostral wider (1.7 mm) than high (0.7 mm), in contact with first supralabials, nasals, and frontonasal ( Figs. 4 A, B ; 6 A, B ); nasals not in contact; nasal posteriorly in contact with slightly smaller anterior loreal; laterally widely in contact with first supralabial and slightly contacting second supralabial. A large single frontonasal in broad contact with rostral anteriorly and frontal posteriorly; widely in contact with nasals, anterior loreal, and prefrontal laterally. Prefrontals separated by frontal. Prefrontals anteriorly in contact with frontonasal, posteriorly in contact with frontal, first supraocular, and first supraciliary scale, laterally in contact with anterior and posterior loreals. Frontal large, nearly twice as long as wide, irregularly shaped, pentagonal with slightly rounded tapering posterior margin, contacting frontonasal, prefrontals, and first supraciliaries anteriorly, in wide contact with first and second supraoculars laterally, in wide contact with frontoparietals posteriorly. Frontoparietals widely in contact with parietals and interparietal scale posteriorly, contacting frontal and second, third, and fourth supraoculars anterolaterally. Interparietal rhomboidal in shape, posteriorly in contact with parietals; parietal eye clearly visible. Parietal anteriorly in contact with frontoparietal, interparietal, and in slight contact with fourth supraocular; laterally touching upper secondary temporal, upper and lower pretemporals; in contact with one (right parietal) and two (left parietal) nuchals posteriorly. Parietal overlapping upper secondary temporal ( Fig. 6 A, B ).

Four supraoculars, second the largest, decreasing in size in both directions. Scales on lateral aspect of head with small pits (likely for sensory papillae), scattered all over their surface ( Fig. 4 A –С). Nostrils with lateral orientation, slightly oval, posterior edge oriented diagonally upward, located in center of nasal. Nasal undivided. Postnasals absent. Anterior and posterior loreals roughly quadrangular, posterior loreal wider than anterior loreal; anterior loreal anteriorly in contact with nasal and frontonasal, posteriorly in contact with posterior loreal and prefrontal, laterally in contact with second supralabial. Posterior loreal anteriorly in contact with anterior loreal and prefrontal, posteriorly in contact with first enlarged supraciliary scale, preoculars, and presubocular, laterally slightly touching second and widely in contact with third supralabials. Two preoculars, the upper one smaller than the lower one; two presuboculars. Anterior presubocular located between the lower edge of anterior preocular, posterior margin of posterior loreal, and upper edge of third supralabial. Middle presubocular located between the anterior presubocular and the upper edges of third and fourth supralabials. Posterior presubocular located between the posterior margin of the middle presubocular and the upper edges of fourth and fifth supralabials. Middle and posterior presuboculars separated from postsuboculars by protruding upper edge of fifth supralabial. Upper eyelid bordered by six supraciliaries and ten ciliary scales; supraciliary row not interrupted. An enlarged scale located between first two supraciliaries, upper preocular and first two ciliary scales. Lower eyelid with 16 ciliary scales; scales covering lower eyelid slightly oval or diamond-shaped, tightly adjacent, overlapping neighboring scales. Lower eyelid with oval, horizontally oriented, large transparent window (PDD 0.58 mm). Upper edge of transparent window in contact with lower edge of ciliaries, comprising almost half of horizontal diameter of orbit in length. Seven supralabials, gradually increasing in size, sixth and seventh supralabials the largest; fifth supralabial located below center of eye; fourth, fifth and sixth supralabials separated from lower edge of eye by presuboculars, postsuboculars, and by a row of small scales. Two postoculars; upper one three times larger than lower one, anteriorly in contact with last supraciliary and last supraocular, posteriorly in contact with upper pretemporal, laterally in contact with lower postocular and last ciliary scale; lower postocular anteriorly in contact with upper one and small scales, separating it from eyelid, posteriorly in contact with upper and lower pretemporals, laterally in contact with upper postsubocular and last ciliary scale. Three postsuboculars, upper one the smallest, posteriorly in contact with lower pretemporal and primary temporal, laterally in contact with middle postsubocular; middle postsubocular in contact with primary temporal posteriorly and with fifth and sixth supralabials laterally; lower postsubocular located between upper edges of fifth and sixth supralabials, middle postsuboculars and a row of small scales under lower eyelid. One large rhomboidally shaped primary temporal anteriorly in contact with lower pretemporal, two postsuboculars and sixth supralabial, posteriorly in contact with upper and lower secondary temporals, and seventh supralabial. Two secondary temporals, upper one the largest, parietal and lower secondary temporal overlap upper secondary temporal, secondary temporals anteriorly in contact with parietal, lower pretemporal, primary temporal and seventh supralabial, posteriorly in contact with nuchal, upper and lower tertiary temporals and upper postsupralabial. Two tertiary temporals; lower one two times larger than upper one; lower one overlapping upper one. Two equally sized, posteriorly elongated postsupralabials posterior to seventh supralabial. Two rows of enlarged scales between postsupralabials and anterior edge of ear opening. Ear opening large, tympanum deeply sunk, not covered with scales, with no projecting ear lobules on its anterior edge ( Fig. 4 A, B ; 6 A, B ).

Seven infralabials, sixth the largest. Mental scale wider than long, with concave posterior margin. Anterior postmental single, large, nearly three times the length of mental, laterally postmental widely in contact with first and second infralabials on both sides. First pair of chin shields medially in contact each other, laterally in contact with second and third infralabials, slightly touching anterior edge of fourth infralabials. Second pair of chin shields in contact with fourth infralabials, separated by one subequal rhomboidally shaped gular scale. Third pair of chin shields touching fourth and widely in contact with fifth infralabials, separated by three subequal rhomboid gular scales ( Figs. 4 C ; 6 C ).

Dorsal scalation heterogeneous, composed of smaller cycloid, imbricate scales laterally and a series of slightly enlarged, broad vertebral scales; the latter include four pairs of nuchals starting from behind parietals followed by four full and half on each side rows of scales (0.5-4-0.5) between dark dorsolateral stripes on the upper lateral edges of the body, each nearly half the size of a nuchal scale ending slightly beyond the groin; roughly two to four times larger than adjoining dorsolateral scales. Paravertebral scale series composed of 60 scales, including nuchals. Scales around midbody in 26 rows. Dorsal scales smooth and glossy. Scales on lateral aspects of neck and limbs much smaller and similar in shape to those on body flanks. Ventral scales similar in size and shape to those on flanks; midventral scale series composed of 72 scales when counted from first pair of chin shields (including gulars) to precloacal scales. Medial pair of precloacal scales enlarged; outer scales overlapping medial ones. Tail complete; tail scales smooth, imbricate; all equal in shape except subcaudals, which are greatly widened (twice the size of vertebral row) ( Figs. 4 F, G ; 5 A, B ).

Hemipenes ( Fig. 5 C, D ) slightly curved in dorsolateral aspect, short, rose-shaped, bilobed, and symmetrical, divided into two lobes approximately in middle of their length. Hemipenal lobes well-developed, rounded, showing prominent fleshy extensions at their distal ends. Lobes and truncus with smooth surfaces, lacking ornamentation, cup-shaped, papillary, or spiny structures. Truncus slightly widens from its base to the bifurcation point. Two large fleshy folds present at the bifurcation point of truncus. Sulcus spermaticus visible at truncus base, distally concealed in folds at base of lobes. Lobes with lateral orientation, each curved outward from organs’ central axis. Lobes well-developed, rounded, showing prominent fleshy extensions at distal ends. Sulcus opening wide, arytenoid, directed ventrally. Terminal awns short, large, fleshy, and directed inward. On dorsal side of each lobe (on the opposite side from the base of the sulcus opening), two large expansions with papillary apices and two ventrally oriented expansions without papillary apices. Total length of hemipenis: 4.1 mm; length of each lobe: 2.3 mm; length of truncus: 1.8 mm; width of lobe: 1.9 mm; width of truncus in its middle point: 1.0 mm (measured on the left side).

Coloration in life ( Figs. 3 , 5 ). The dorsal surface of the body olive-brown with irregularly scattered streak-like dark spots, no longer than one dorsal scale; the dorsal surface of the head and tail colored a richer dark-brown; limbs deep-brown dorsally, densely covered with yellow-brown spots. The dorsolateral stripe originates from the snout, traverses the upper edge of the nasal and loreals, is interrupted by the eye, and continues immediately behind the eye, continuing along flanks above forelimbs and hindlimbs, reaching the caudal terminus. The dorsolateral stripe is very narrow (however, this is visible only on preserved specimens; in life, its upper edge is contrasting, and the lower one merges with the color of the flanks), one scale wide, dark, without light spots; the upper part of the flanks dark-brown without contrasting white spots, sometimes with small pale cream speckles; the brown coloration of the flanks becomes paler towards the lower edge, giving way to a lighter color of the belly along the lower edge, blurring the dark-brown color into separate irregularly scattered dark spots. Ciliaries gold, creating a golden rim around the eye; in females, this coloring is more contrasting. Iris deep-brown. The parietal eye is dark-brown and blends with the dark-brown coloration of the upper surface of the head. The venter is lemon yellow; the belly, limbs, base, and first quarter of the tail are colored. The ventral surface of the head and most of the tail are gray-white. Venter lacking black spots, but contrasting black speckles outline the head along the outer edge of the chin shields, the edges of the belly, and black spots are scattered along the ventral surface of the tail.

Coloration in preservative ( Fig. 4 ). In preservative, dorsal surfaces fade to dark grayish brown; the dorsolateral stripe and dark spots on the body become more contrasting; the dorsolateral stripe acquires a light acanthus along the upper edge. The parietal eye becomes contrasting and visible. The lemon coloration of the ventral surface of the neck, belly, and base of the tail is completely faded. The ventral surfaces of the head, throat, belly, limbs, and tail become grayish with a bluish tint; palmar surfaces of hands, fingers, and toes pale gray.

Variation. The paratypes are similar to the holotype in most morphometric and meristic characters and color pattern, with the following character variations: (1) PVSR and VSR: 56–63 and 66–76, respectively; (2) AGSR: 45–54; (3) MBSR from 26 to 28; (4) the prefrontals are generally separated, rarely touching each other; in VRTC NAP14092 a pholidosis anomaly is observed—the space between the prefrontals is occupied by a shield duplicating the left prefrontal (three tightly contacting prefrontal scales); (5) pairs of nuchal scales from three to four; (6) FL4 and TL4: 7–10 and 11–13, respectively; (7) the rim around the eye, formed by a ring of gold-colored ciliaries, is more contrasting in females; (8) the venter is lemon yellow in males and cream yellow in females; (9) the regenerated tail is orangish and lacks black spots. Other minor variations are summarized in Table 3.

No significant morphological differences were observed between the Chieu Lau Thi and Tay Con Linh populations, both from Ha Giang Province, northern Vietnam. Specimens from the type locality at Chieu Lau Thi Mt. (n=9) differ from those from Tay Con Linh Mt. (n=6) by their generally smaller body size (mean SVL 43.7 mm [48.2– 38.2 mm] vs. 45.9 mm [47.8– 44.3 mm]), generally shorter acetabulum to groin distance (mean AGD 24.3 mm [28.2– 20.6 mm] vs. 27.1 mm [29.4– 23.3 mm]), and a slightly broader tail base (mean TD 1.1 mm [1.3– 0.9 mm] vs. 1.2 mm [1.2– 1.1 mm]). However , the ranges of these characters overlap significantly, and the observed differences are most likely explained by the predominance of males in the Chieu Lau Thi Mt. sample. The ranges of meristic characteristics among the two populations also exhibited substantial overlap. Notable differences between the population from the type locality and Tay Con Linh Mt. include a generally higher number of midbody scale rows (26–27 vs. always 26), ventral scale rows (44–52 vs. 44–49), and generally fewer numbers of paravertebral scale rows (mean PVSR 58.8 [62–56] vs. 59.7 [62–58]) and fewer numbers of subdigital lamellae on toe IV (mean TL4 11.9 [13–11] vs. 12.7 [13–12]) (see Table 3) .

Comparisons. Scincella alia sp. nov. can be distinguished morphologically from closely related congeners from northern Vietnam and southern China; the diagnostic characters are as summarized in Table 4.

In our phylogenetic analysis, Scincella alia sp. nov. is closely related to S. devorator , S. liangshanensis , S. fansipanensis , S. wangyuezhaoi , S. monticola , and S. potanini . Nevertheless, Scincella alia sp. nov. can be readily distinguished from S. devorator by having fewer midbody scale rows (26–28 vs. 28–30), subdigital lamellae on toe IV (11–13 vs. 17–19), and dorsal scale rows between the dorsolateral stripes (0.5–4–0.5 vs. 0.5–6–0.5), by the absence of postnasal (vs. present), by prefrontals being usually separated (73%) (vs. in contact), and by a fundamentally different coloration (dark-brown without dorsal stripes vs. gray with a wide dorsal stripe). Scincella alia sp. nov. differs from S. liangshanensis by having a greater number of midbody scale rows (26–28 vs. 23–27) and fewer paravertebral scale rows (56–63 vs. 69–80), primary temporals (1 vs. 2), and by more often separated prefrontals (vs. prefrontals generally in contact). Scincella alia sp. nov. differs from S. fansipanensis by a smaller body size (SVL 38.2–48.2 mm vs. 43.5–59 mm), by having a greater number of midbody scale rows (26–28 vs. 22–24), ventral scale rows (66–76 vs. 58–64), and by the absence of large contrasting white spots on the sides of the body and head, and large wide black spots along the edges of belly (vs. present). Scincella alia sp. nov. cies differs from S. wangyuezhaoi by having fewer midbody scale rows (26–28 vs. 27–30), paravertebral scale rows (56–63 vs. 60–75), subdigital lamellae on finger IV (7–10 vs. 9–11) and on toe IV (11–13 vs. 14–15), dorsal scale rows between dorsolateral stripes (0.5–4–0.5 vs. 0.5–6–0.5), and primary temporals (1 vs. 2). Scincella alia sp. nov. further differs from S. potanini and S. monticola by a greater TD/PDD ratio (1.63–2.18 vs. 0.79–1.25 and 0.62–1.11, respectively), by a generally greater number of midbody scale rows (26–28 vs. 24–27 and 23–25, respectively), and a fewer number of paravertebral scale rows (56–63 vs. 62–80 and 65–74, respectively). Furthermore, the new species differs from S. potanini also in dorsal coloration pattern with irregularly shaped dark spots (vs. a median black line).

The morphological characteristics that set Scincella alia sp. nov. apart from its Asian congeners are as follows. The new species differs from S. schmidti ( Barbour, 1927) by fewer paravertebral scale rows (56–63 vs. 66), and more nuchals (3–4 pairs vs. 1 pair); from S. tsinlingensis (Hu & Zhao, 1966) by a greater TD/PDD ratio (1.63–2.18 vs. 0.80–1.14) and fewer ventral scale rows (66–76 vs. 83–98), and subdigital lamellae on toe IV (11–13 vs. 13–16); from S. huanrenensis ( Zhao & Huang, 1982) by a greater TD/PDD ratio (1.63–2.18 vs. 0.61–1.14); from S. barbouri ( Stejneger, 1925) , S. doriae , S. formosensis , S. modesta ( Günther, 1864) , S. przewalskii ( Bedriaga, 1912) , and S. reevesii by having fewer dorsal scale rows between dorsolateral stripes (4 vs. 6–8); from S. barbouri by a smaller number of paravertebral scale rows (56–63 vs. 70–79), fewer subdigital lamellae on toe IV (11–13 vs. 15–17), and in dorsal color pattern (with irregularly shaped dark spots vs. five indistinct lines); from S. doriae by smaller number of midbody scale rows (26–28 vs. 30–32), by fewer subdigital lamellae on toe IV (11–13 vs. 15–18), and by toes not in contact with fingers when limbs adpressed (vs. overlapping); from S. formosensis by lower HLL/ SVL ratio (0.25–0.34 vs. 0.34–0.39); from S. modesta by the number of subdigital lamellae on toe IV (11–13 vs. 12–17), by toes not in contact with fingers when limbs adpressed (vs. overlapping), and in dorsal color pattern (with irregularly shaped dark spots vs. indistinct lines of black dots); from S. przewalskii by more supraoculars (4 vs. 3) and fewer subdigital lamellae on toe IV (11–13 vs. 17); from S. reevesii by fewer subdigital lamellae on toe IV (11–13 vs. 15–18), midbody scale rows (26–28 vs. 28–34), and by having more nuchals (3–4 pairs vs. 0–1 pair); from S. apraefrontalis by more midbody scale rows (26–28 vs. 18), more paravertebral scale rows (56–63 vs. 52), more ventral scale rows (66–76 vs. 50), more infralabials (7 vs. 5), more subdigital lamellae on toe IV (11–13 vs. 8–9), and by the presence of prefrontals (vs. absent); from S. badenensis by fewer midbody scale rows (26–28 vs. 32–36), fewer dorsal scale rows between dorsolateral stripes (4 vs. 10), more nuchal pairs (3–4 vs. 0–1), fewer supraciliaries (6 vs. 8–9), fewer supralabials (7 vs. 7–8), fewer subdigital lamellae on toe IV (11–13 vs. 18–20), by having toes not in contact with fingers when limbs adpressed (vs. overlapping), and in dorsal color pattern with irregularly shaped dark spots (vs. no dark spots); from S. baraensis by fewer midbody scale rows (26–28 vs. 30), fewer dorsal scale rows between dorsolateral stripes (4 vs. 8), more ventral scale rows (66–76 vs. 58–64), fewer supraciliaries (6 vs. 8), fewer subdigital lamellae on finger IV (7–10 vs. 12–13) and on toe IV (11–13 vs. 18–20), and by the absence of auricular lobules (vs. present); from S. boettgeri ( Van Denburgh, 1912) by fewer subdigital lamellae on toe IV (11–13 vs. 15–16); from S. darevskii by smaller size (SVL 38.2–48.2 mm vs. 88.6 mm), by fewer dorsal scale rows between dorsolateral stripes (4 vs. 6), fewer supraoculars (4 vs. 5), fewer subdigital lamellae on toe IV (11–13 vs. 17), more ventral scale rows (66–76 vs. 64–66), and by the absence of auricular lobules (vs. present); from S. dunan by a greater number of ventral scale rows (66–76 vs. 55–67), fewer subdigital lamellae on toe IV (11–13 vs. 13–17), by unbroken dorsolateral stripes (vs. dorsolateral stripes broken by light spots), and by small dark irregular spots densely scattered ventrally from the dorsolateral stripes (vs. large dark spots); from S. melanosticta by fewer midbody scale rows (26–28 vs. 30–37), fewer dorsal scale rows between dorsolateral stripes (4 vs. 10), fewer subdigital lamellae on toe IV (11–13 vs. 16–22), fewer supraciliaries (6 vs. 8–9), by the presence of nuchals (vs. absent), and by having toes not in contact with fingers when limbs adpressed (vs. overlapping); from S. nigrofasciata by having more pairs of nuchals (3–4 vs. 0–1), fewer midbody scale rows (26–28 vs. 32–33), fewer paravertebral scale rows (56–63 vs. 69–74), fewer dorsal scale rows between dorsolateral stripes (4 vs. 8), fewer subdigital lamellae on toe IV (11–13 vs. 15–17), by having toes not in contact with fingers when limbs adpressed (vs. overlapping), and in dorsal color pattern (irregularly shaped dark spots vs. 5–7 regular discontinuous stripes); from S. ochracea by fewer midbody scale rows (26–28 vs. 30–32), fewer dorsal scale rows between dorsolateral stripes (4 vs. 6 or 8), fewer subdigital lamellae on toe IV (11–13 vs. 15–19), more supralabials (7 vs. 5), by having toes not in contact with fingers when limbs adpressed (vs. overlapping), by the absence of auricular lobules (vs. present), and in dorsal color pattern (irregularly shaped dark spots vs. a dark vertebral stripe); from S. punctatolineata ( Boulenger, 1893) by nuchals present (vs. absent); from S. rara by having a double row of lamellae beneath toes and fingers II– IV (vs. single row of lamellae); from S. rufocaudata by having more pairs of nuchals (3–4 vs. none), fewer midbody scale rows (26–28 vs. 30–34), fewer dorsal scale rows between dorsolateral stripes (4 vs. 10), fewer paravertebral scale rows (56–63 vs. 67–69), fewer supraciliaries (6 vs. 8), fewer subdigital lamellae on toe IV (11–13 vs. 15–20), and by having toes not in contact with fingers when limbs adpressed (vs. overlapping); from S. rupicola by fewer midbody scale rows (26–28 vs. 33–36), fewer paravertebral scale rows (56–63 vs. 68–73), fewer dorsal scale rows between dorsolateral stripes (4 vs. 8), fewer subdigital lamellae on toe IV (11–13 vs. 17–21), fewer supraciliaries (6 vs. 7–9), more pairs of nuchals (3–4 vs. 0–1), and by having toes not in contact with fingers when limbs adpressed (vs. overlapping); from S. vandenburghi ( Schmidt, 1927) by fewer dorsal scale rows between dorsolateral stripes (4 vs. 6) and by having unbroken dorsolateral stripes (vs. dorsolateral stripes broken by light spots); from S. victoriana ( Shreve, 1940) by scales on dorsum and tail smooth (vs. keeled); and from S. ouboteri by having fewer midbody scale rows (26–28 vs. 30–32), fewer dorsal scale rows between dorsolateral stripes (4 vs. 8), fewer paravertebral scale rows (56–63 vs. 65–73), fewer subdigital lamellae on toe IV (11–13 vs. 18–20), by having toes not in contact with fingers when limbs adpressed (vs. overlapping), by the absence of dark dorsal stripes (vs. present), and by the absence of auricular lobules (vs. 3 or 4 lobules present).

Species Scincella S. cf. S. cf. S. cf. S. S. cf. S. S. S. S. S. potanini S. truongi S.

alia monticola monticola monticola monticola monticola monticola fansipanensis liangshanensis wangyuezhaoi tsilingensis sp. nov.

PrC 2 2 n /a 2 2 n /a 2 2 2 2 2 2 2

FTSR 2 n/a n/a n/a n/a n/a n/a n/a 2 2 2 2 2

FL4 7–10 9 7 7 n /a n/a 8–10 7–9 8–11 9–11 7–10 10 9–10

TL4 11–13 11 11 11 12 10–13 10–12 10–12 10–15 14–15 10–13 13–15 13–16

F-H no n/a no no no n/a no no no\in contact no no no

References This study Nguyen et Nguyen et Pham et Schmidt Inger et al. Jia et al. Okabe et al. Jia et al. (2024) Jia et al. (2023) Jia et al. Pham et Jia et al. al. (2010a) al. (2010b) al. (2015) (1925) (1990) (2024) (2024) (2023) al. (2025) (2023)

Finally, the new species differs from the recently described S. truongi from Son La Province of northern Vietnam by having a smaller body size (SVL 38.2–48.2 mm vs. 49.0–59.0 mm), greater ear diameter (TD/PDD 1.6–2.2 vs. 1.3–1.5), fewer numbers of superciliary scales (6 vs. 7), postoculars (1 vs. 2), primary temporals (1 vs. 2), fewer dorsal scale rows between the dorsolateral stripes (4 vs. 6), fewer subdigital lamellae on toe IV (11–13 vs. 13–15), greater number of superciliary scales (6 vs. 7), postoculars (1 vs. 2), primary temporals (1 vs. 2), less dorsal scale rows between the dorsolateral stripes (4 vs. 6), fewer subdigital lamellae on toe IV (11–13 vs. 13–15), greater number of preoculars (2 vs. 1), presuboculars (3 vs. 2), postsuboculars (3 vs. 2), and by the absence of projecting ear lobules (vs. present).

Distribution. The new species is currently known only from Tay Con Linh Mt. and Chieu Lau Thi Mt., both summits are located in 26 km direct distance from each other and belong to the Tay Con Linh Range in Ha Giang Province, northeastern Vietnam, at high elevations ranging from 1,850 to 2,370 m asl. However, we anticipate that its distribution may extend much further, potentially encompassing adjacent mountainous regions on the left bank of the Red River (Sông Hồng) in Ha Giang, Tuyen Quang, and Cao Bang Provinces of northeastern Vietnam, as well as the Yunnan Province in China (e.g., Laojun Mt.).

Natural history notes and conservation status. The ecology of the new species remains largely unknown. On Chieu Lau Thi Mt. in Ha Giang Province, northeastern Vietnam, lizards were observed during February 2023 at elevations ranging from 1,850 –2,100 m asl. At elevations of 2,070 –2,100 m asl., skinks were found under large logs and in grass tussocks in a severely disturbed, low-canopy mountain forest ( Fig. 7 A, B ) fragment formed by representatives of families Lauraceae (Juss.) , Fagaceae (Dumort.) , and Meliaceae (Juss.) , located directly on the mountain ridge near Chieu Lau Thi peak. However, the specific locations where the lizards were encountered were deforested areas covered with shrub vegetation and mixed grasses, used as trails and livestock grazing grounds. At an elevation of 1,850 m asl., skinks were found under anthropogenic debris (cement bags) along roadsides within agricultural settlements. On Tay Con Linh Mt., skinks were observed within a similar elevation range. At elevation 1,920 m asl., skinks were found in leaf litter on deforested plots cleared for Chinese cardamom, Lanxangia tsaoko (Crevost & Lemarié) Newman & Škorničk. , plantations within broad-leaved evergreen high-canopy forest ( Fig. 7 C ) dominated by representatives of families Theaceae (Mirb.) , Lauraceae , Rutaceae (Juss.) , Rubiaceae (Juss.) , and Moraceae (Gaudich.) with sparse undergrowth and well-developed herbaceous vegetation from Urticaceae (Juss.) and ferns on clearings and ravines. At an elevation of 2,370 m asl., skinks were found burrowed in the soil in primary high-canopy evergreen and deciduous mountain forests ( Fig. 7 D ) with a thick leaf litter layer, dominated by trees from families Lauraceae , Fagaceae , Theaceae , Meliaceae , and Magnoliaceae (Juss.) , with a low undergrowth layer of bamboo Bambusa (Schreb.) . The lizards were hibernating burrowed in soil coiled into a tight ball at a depth of 10–15 cm.

During February 2024 on Chieu Lau Thi Mt., daytime temperatures reached 20°C, while nighttime temperatures remained around 8°C, likely dropping further at the surveyed elevations. During midday (12:00–13:00 h), skinks showed low activity and remained within the substrate but were not in hibernation. By late April on Tay Con Linh Mt. at lower elevations (up to 2000 m asl.), daytime temperatures reached 22°C, and nighttime temperatures stayed around 14°C. Within this elevation range, skinks were active both during the day (12:00–14:00 h) and at twilight (18:00–22:00 h). However, at elevations above 2000 m asl., daytime temperatures reached only 19°C, and nighttime temperatures remained around 10°C. At an elevation of 2,369 m asl., skinks were found in a state of hibernation, burrowed 5–10 cm deep within the substrate composed of small rocks, humus, and fine roots along a trail slope. The skinks were coiled in the substrate and remained inactive for an extended period after being uncovered.

Conservation status. Though our study suggests that Scincella alia sp. nov. is endemic to the Tay Con Linh Range in the Ha Giang Province of Vietnam, its occurrence in the adjacent parts of the Yunnan Province of China is expected. In the surveyed habitats in Ha Giang Province, the new species inhabits both primary ecosystems and human-altered environments, occurring close to human settlements. Despite the progressing deforestation, plantation development, and livestock overgrazing, the surveyed populations demonstrated high abundance. The new species does not appear to hold value for locals in terms of medicine or as a food resource. Therefore, we propose to classify this species as a Least Concern (LC) species following IUCN’s Red List categories ( IUCN Standards and Petitions Subcommittee 2019) and the specific recommendations for the Scincidae ( Chapple et al. 2021) .

Figures

FIGURE 3. Holotype of Scincella alia sp. nov. (ZMMU Re-18147, adult male) in situ. Photograph by A. M. Bragin.

FIGURE 4. Holotype of Scincella alia sp. nov. (ZMMU Re-18147, adult male, in preservative).A—Right lateral view of head; B–Ventral view of head; C. Dorsal view of head; D—Ventral view of left forelimb; E—Ventral view of left hindlimb; F—Dorsal view of body; G–Ventral view of body. Scale bars: A–E = 2 mm; F, G = 10 mm. Photographs by A. M. Bragin.

FIGURE 5. Holotype of Scincella alia sp. nov. (ZMMU Re-18147, adult male, prior to preservation).A—Dorsal view of body; B—Ventral view of body; C—Dorsal view of right hemipenis, fully everted; D—Ventral view of right hemipenis, fully everted. Scale bars: A, B = 10 mm; C, В = 2 mm. Photographs by A. M. Bragin.

FIGURE 6. Head scale nomenclature and their positional relationship and size illustrated by the adult male Scincella alia sp. nov. (holotype, ZMMU Re-18147). A. Right lateral view; B. Dorsal view; C. Ventral view. Terminology is modified from Ouboter (1986) and Grismer et al. (2019).AL—anterior loreal, C—ciliary, Cs—chin-shield; F—frontal, FN—frontonasal, FP— frontoparietal, IF—infralabial, IP—interparietal, LST—lower secondary temporal, LTT—lower tertiary temporal, LPT—lower pretemporal, LPSL—lower postsupralabial, M—mental, N—nasal, Nu—nuchal, P—parietal, PF—prefrontal, PL—posterior loreal, PM—postmental, PR—preocular, PRS—presubocular, PT—primary temporal, PSO—postsubocular, PO—postocular, R—rostral, SC—supraciliaries, SL—supralabial, SO—supraocular, UPT—upper pretemporal, UPSL—lower postsupralabial, UST—upper secondary temporal, and UTT—upper tertiary temporal, *—small scales separating supralabials from the lower eyelid. Illustration by A. M. Bragin.

FIGURE 7. Habitats of Scincella alia sp. nov. in Ha Giang Province, Vietnam: A, B—Severely disturbed low-canopy forest fragment at elevation 2,094 m asl. and microhabitat at the type locality on Chieu Lau Thi Moutain; C—Broad-leaved evergreen high-canopy forest with Chinese cardamom plantations at elevation 1,916 m asl. on Tay Con Linh Moutain; D—Primary highcanopy evergreen and deciduous forest at elevation 2,369 m asl. on Tay Con Linh Mountain. Photographs by A. M. Bragin.