Lipinia sekayuensis, Grismer, L. Lee, Ismail, Lukman H. B., Awang, Muhammad Taufik, Rizal, Syed A. & Ahmad, Amirrudin B., 2014

Grismer, L. Lee, Ismail, Lukman H. B., Awang, Muhammad Taufik, Rizal, Syed A. & Ahmad, Amirrudin B., 2014, A new species of lowland skink (genus Lipinia Gray, 1845) from northeastern Peninsular Malaysia, Zootaxa 3821 (4), pp. 457-464 : 459-463

Lipinia sekayuensis sp. nov.

Sekayu Striped Skink Figs. 2 , 3

Holotype. Adult male ( LSUHC 11593) collected by Nur Afny Syazwany Abu Zarim on 30 March 2013 at 1200 hrs at Hutan Lipur Sekayu, Terengganu, Peninsular Malaysia (4° 58.127 N, 102° 57.433 E at 33 m asl).

Diagnosis. Lipinia sekayuensis sp. nov. can be distinguished from all other species of Lipinia by having the combination of an adult SVL of 42.3 mm; six supralabials; five infralabials; four supraoculars; prefrontals widely separated; two loreals; fused frontoparietals; lower eyelids bearing a large, transparent disc; 21 midbody scale rows; 56 paravertertebral scale rows; 65 ventral scale rows; enlarged, precloacal scales; 10 subdigital lamellae on the third finger; 11, 15, and seven lamellae on the third, fourth, and fifth toes, respectively; distal subdigital lamellae keeled; a median row of slightly enlarged, subcaudal scales; a generally unicolor, dark-brown dorsum bearing nine very faint, diffuse, darker stripes; and an external ear opening replaced by a scaly, auditory depression ( Table 1 ).

Lipinia sekayuensis sp. nov. Lipinia surda Lipinia surda LSUHC BM LSUHC 11593 1946.8.16.52 (syntype) 4801 snout to forelimb (Sn-ForeL) 13.0 / / Description of holotype ( Figs. 2 , 3 ). Adult male reaching 41.2 mm SVL; head somewhat elongate, triangular and pointed in dorsal profile; rostral wider than high, in broad contact with frontonasal; frontonasal wider than long; prefrontals moderate in size, separated; frontal elongate, triangularly shaped, in contact with first two supraoculars; four supraoculars; frontoparietals fused, contacting posterior portion of second and all of third and fourth supraoculars, contacting parietals and interparietal posteriorly; interparietal diamond-shaped, slightly projecting posteriorly, parietal eyespot in posterior portion of scale; parietals large, in contact posterior to interparietal, making point contact with posterior margin of fourth supraocular anteriorly; single pair of large, nuchal scales; nasals moderate in size, widely separated, trapezoidal, contacting lateral margin of frontonasal and rostral anteriorly, first loreal posteriorly, first supralabial ventrally; nostril located in center of nasal scale; anterior loreal rectangular, posterior loreal square; two similarly sized preoculars in contact with second loreal; eight supraciliaries, anteriormost in contact with prefrontal; two similarly sized pretemporals; single primary temporal below pretemporals; external ear opening replaced by a scaly, auditory depression; four suboculars, subocular row interrupted by large fifth supralabial contacting eye; six supralabials; two postsupralabials; single, large, secondary temporal contacting parietal; no small, granular scales at posterior corners of eye; lower eyelid bearing an enlarged transparent disc; mental wider than long; single, large, squarish postmental contacting first and second infralabials; two enlarged sublabials following postmental contacting medially; sublabials contacting second and third infralabials; second pair of large sublabials making point contact medially; six infralabials; external ear opening absent.

Body scales smooth, cycloid, imbricate; dorsal scales transversely elongate, ventral scales not so; 21longitudinal scale rows around midbody; 56 paravertebral scale rows; 65 ventral scale rows; limbs widely separated when adpressed; hind limbs slightly larger than forelimbs; scales of dorsal surface of limbs same size as those of ventral surface; palmar and plantar scales, rounded, smooth, slightly raised; scales of dorsal surfaces of digits in a double row; subdigital lamellae on proximal one-half of digits transversely expanded and raised; distal lamellae bearing a single keel; numbers of subdigital lamellae of fingers I–V are 6, 9, 10, 10, 7, respectively; numbers of subdigital lamellae of toes I–V are 8, 9, 11, 15, 7, respectively; tail moderate, cylindrical; median subcaudal row bearing slightly enlarged scales.

Coloration in alcohol and life ( Fig. 3 ). The dorsal ground color of the head, body, limbs and tail dark-brown; three faint, diffuse darker brown stripes on flanks and three similar stripes on dorsum (totaling nine stripes); labial scales and mental scale bearing a central, light-colored spot; ventral surfaces beige with faint, dark stippling in longitudinal rows.

Distribution. Lipinia sekayuensis sp. nov. is known only from the type locality of Hutan Lipur Sekayu, Terengganu, Peninsular Malaysia ( Fig. 1 ). It is likely this species has a much broader range throughout the lowlands of northeastern Peninsular Malaysia.

Natural history. Lipinia sekayuensis sp. nov. was observed crawling during the day near chalets built along Sungai (river) Peres in the lowland dipterocarp forest of Hutan Lipur Sekayu. In this regard, it is similar to L. surda which has also been found near human habitations in disturbed forests on both Pulau Tioman and Pulau Aur in the Seribuat Archipelago ( Grismer 2011; Fig. 1 ). The elongate body, reduced limbs and toes, and the lack of an external ear opening suggest L. sekayuensis sp. nov. probably spends much of its time underground in soft soils and beneath surface debris.

Etymology. The specific epithet, sekayuensis is an adjective in reference to the type locality of Hutan Lipur Sekayu.

Comparisons. Lipinia sekayuensis sp. nov. can be differentiated from L. albodorsalis (Vogt) , L. auriculata (Taylor) , L. leptosoma , L. longiceps (Boulenger) , L. macrotympanum (Stoliczka) , L. miangensis (Werner) , L. nototaenia (Boulenger) , L. occidentalis Günther , L. pulchella (Gray) , L. quadrivitatta (Peters) , L. semperi (Peters) , L. venemai , L. vittigera (Boulenger) , L. vulcania Girard , and L. zamboangensis (Brown & Alcala) in lacking as opposed to having an external ear opening. From the remaining 11 species, L. sekayuensis sp. nov. differs from 10 of them ( L. cheesmanae Parker , L. infralineolata [Günther], L. nitens [Peters], L. noctua [Lesson], L. rabori [Brown & Alcala], L. relicta [Vinciguerra], L. rouxi Hediger , L. septentrionalis Günther , and L. subvittata [Guunther]), in lacking a boldly marked, lineate, dorsal pattern. Lipinia sekayuensis sp. nov. closely resembles L. surda in ear morphology and color pattern but is separated from it by having fewer paravertebral scale rows (56 vs. 64 or 65); fewer ventral scale rows (65 vs. 75); fewer subdigital lamellae on the third and fourth fingers (10 vs. 13 or 14) and the third, fourth, and fifth toes (11 vs. 14 or 15, 15 vs. 17–20, and seven vs. 13 or 14, respectively); a median row of slightly enlarged subcaudals as opposed to not having enlarged subcaudals; a dark-brown vs. beige ground color in life; and nine diffuse, faint darker brown stripes on the flanks and dorsum as opposed to no striping.

The numbers of infralabials; midbody scale rows; first, second, and fifth sudigital finger lamellae; and first and second subdigital toe lamellae currently separate Lipinia sekayuensis sp. nov. from L. surda but these ranges will most likely overlap with the acquisition of additional material of both species and are thus not considered diagnostic ( Table 1 ). However, owing to the degree of difference in the size of the transversely enlarged subcaudals and the wide range in numbers of paravertebral and ventral scale rows; third and fifth finger subdigital lamellae; and third, fourth, and fifth subdigital toe lamellae ( Table 1 ), it is likely that the acquisition of additional material will not preclude the discrete, diagnostic value of these characters. Additionally, a nearly unicolor color pattern and the absence of an external ear opening—character states that separate L. sekayuensis sp. nov. from 26 of the 27 remaining species of Lipinia —are highly unlikely to vary with the discovery of additional specimens.

Figures

FIGURE 1. Distribution of Lipinia sekayuensis sp. nov. and L. surda in Peninsular Malaysia and the islands of the Seribuat Archipelago. Stars indicate type localities.

FIGURE 2. Upper: dorsal view of holotype of Lipinia sekayuensis sp. nov. (LSUHC 11593) from Hutan Lipur Sekayu, Terengganu, Peninsular Malaysia. Lower: dorsal view of L. surda (LSUHC 4801) from Pulau Aur, Johor, Peninsular Malaysia.

FIGURE 3. Illustrations of the head of the holotype of Lipinia sekayuensis sp. nov. in dorsal (upper) and lateral (lower) views showing the transparent disc (TD) on the lower eyelid, the condition of the prefrontals (PF) and fronoparietals (FP), and the location of the scaly, auditory depression (red circle) — some of the key features used in the identification of the genus.

Tables

TABLE 1. Diagnostic characters separating Lipinia sekayuensis sp. nov. from L. surda. Abbreviations are listed in the Materials and Methods.

	Hutan Lipur Sekayu	Sungai Buloh	Pulau Aur
sex	male	/	female
infralabials	5	6	7
midbody scale rows	21	20	20
paravertebral scale rows	56	65	64
ventral scale rows	65	75	75
1st finger	6	7	7
2nd finger	9	11	11
3rd finger	10	14	13
4th finger	10	13	13
5th finger	7	8	8
1st toe lamellae	8	7	7
2nd toe lamellae	9	11	10
3rd toe lamellae	11	15	14
4th toe lamellae	15	17	20
5th toe lamellae	7	14	13
median subcaudals	slightly enlarged	not enlarged	no tail
dorsal pattern	faint stripes	no stripes	no stripes
dorsal ground color in life	dark-brown	not recorded	beige
snout-vent length (SVL)	42.3	50.0	52.1
tail length (TL)	42.3	100.0	/
axilla-groin length (AxGnL)	24.5	/	31
head length (HeadL)	7.8	/	/
head width (HeadW)	4.1	/	/