Dasia johnsinghi, Vasudevan, Karthikeyan, Silva, Anslem De, Kar, Niladri Bhusan, Naniwadekar, Rohit, Lalremruata, Albert, Prasoona, Rebekah & Aggarwal, Ramesh K, 2012

Vasudevan, Karthikeyan, Silva, Anslem De, Kar, Niladri Bhusan, Naniwadekar, Rohit, Lalremruata, Albert, Prasoona, Rebekah & Aggarwal, Ramesh K, 2012, Phylogeography of Dasia Gray, 1830 (Reptilia: Scincidae), with the description of a new species from southern India, Zootaxa 3233, pp. 37-51 : 40-44

Dasia johnsinghi sp. nov.

Suggested common English name: Barred tree skink

Holotype. ZSIC 25946, adult male, collected from Servalar, Kani Kudi (latitude N 8.65354°, longitude E 77.31387°; WGS 84 datum) in a riverine forest habitat, Mundanthurai plateau, Tamil Nadu, India, on January 25, 2005 by the second author (KV).

Paratype. BNHS 1391 Collected from Kalakkad-Mundanthurai Tiger Reserve in the riverine forest of Tamaraparani River in Mundanthurai, in the southern Western Ghats, Tamil Nadu, India. The specimen was collected on August 18, 1984 by Justus Joshua and deposited by A. J. T. Johnsingh.

Diagnosis. The specimens are placed in the genus Dasia Gray, 1839 on account of possession of the following characters: palatal notch not extending forwards to between the front of the eyes; eyelids well developed; lower eyelid scaly; nostril within the nasal; supranasals present; prefrontals, frontoparietals and interparietal distinct; ear opening small and tympanum sunk.

The new species is characterized by the following combination of characters: second pair of genials widely separated from each other; a single large anterior temporal in contact with supralabials and parietal; vertical slitlike ear opening with a projecting flap-like scale on its anterior inner border; 17 or 18 subdigital lamellae under fourth toe; scales on posterior dorsal body strongly keeled; body colour greenish brown with seven or eight broken, narrow, black cross-bands, each of which is one scale wide and spotted with white; no cross-bands on the neck which has two dorsal and two lateral black stripes; dorsal stripes start on the frontal shield and extend backward up to 13th vertebral scale; lateral stripes starting on the posterior part of anterior loreal and extend backward to the same level as the dorsal stripes

Description of holotype. A medium sized skink (SVL 91.2 mm); head longer than broad (HL/HW ratio 1.16); body elongate (HL/SVL ratio 0.16); snout pointed; head not distinct from neck; rostral shield in contact with first supralabial, anterior nasal, supranasal and frontonasal; supranasals separated from each other; frontonasal about twice as long as prefrontals; prefrontals large and just separated from each other; frontal almost twice as long as frontonasal and longer than its distance from the tip of the snout; frontoparietals about half as long as frontal; interparietal more than half the length of the frontal; parietals separated by interparietal; seven supralabials and six infralabials on both side; nasal divided vertically with nostril in the middle; anterior loreal shorter than posterior loreal; two preoculars and a presubocular on either side; four small postoculars; 7–8 supraciliaries on either side, anterior most being the largest; three smooth cycloid temporal scales; single anterior temporal just touching the parietal with its lower edge wedged between the last two supralabials; a pair of transversely enlarged smooth nuchal scales; mental followed by a single postmental shield; an anterior pair of chin shields in broad contact with each other; posterior pair of chin scales widely separated by a scale; tympanum small and sunken; ear opening a vertical slit with a small projecting flap-like scale on its anterior border; mid-body scales in 22 transverse rows, smooth on the anterior body and ventrals while distinctly keeled on posterior dorsal body and dorsal part of base of tail; posterior dorsal scales with three distinct keels; scales on the dorsal part of base of tail and hind limbs also with two or three strong keels; 48 vertebral scales on a line from nuchal scales to level of cloaca; 57 ventral scales on a line from the scale separating the posterior genial to the enlarged scale row on the anterior border of cloaca; six enlarged preanal scales in a row bordering the anterior margin of the cloaca; 61 enlarged scales under the tail; vertebral scales about 1.7 times larger than ventrals; 18/17 (right/left) subdigital lamellae on the fourth toe; palms with two distinctly enlarged rounded tubercles; heels with five enlarged rounded tubercles; relative length of fingers 4>3>5≥2>1; relative length of toes 4>3>5>2>1.

Colouration in life. The body was bronze-brown dorsally, becoming greenish on the sides. The ventrals were pale bluish white and the lower jaw and sides of the neck were bright yellowish green in life. There were two black stripes on the head, each one scale wide, starting on the third supraocular and adjacent edge of frontal scale and extending parallel to each other, to the level of 13th vertebral scale (fig. 2). Additionally, there was a lateral black stripe about two scale rows wide starting on the posterior part of anterior loreal, passing through the eye, tympanum and extending to the level of 13th vertebral scale along the side of the neck (fig. 3). The lateral and dorsal stripes did not meet. There were no black cross-bands on the neck. The body had seven broken black cross-bands, each of which was one scale wide (fig. 4). Each black scale had a white spot on its posterior edge. These bands were present only on the dorsal and lateral parts of the body and did not continue around the belly. The tail had more than eight similarly colored bands.

Variation in paratype. The paratype agrees well with the holotype except for the following characters: snoutvent length (SVL) 86.3 mm; tail length (TaL) 88.1 mm; head longer than broad (HL/HW ratio 1.31); frontonasal about twice as long as prefrontal; frontal about 1.5 times longer than frontonasal; frontoparietal about 3/4 the length of frontal; eight supralabials and eight infralabials on both sides; 8/9 (right/left) supraciliaries; midbody scales in 24 transverse rows; 43 vertebral scales; 51 ventral scales; 71 transversely enlarged subcaudal scales; and heels with five distinctly enlarged rounded tubercles. Table 1 gives the morphometric measurements of the holotype and the paratype. This specimen was erroneously identified as Dasia subcaeruleum by Wickramasinghe et al. (2011). They report 52 vertebral scales and 56 ventral scales, which differs from our data from the same specimen.

Etymology. Named after Dr. Asir Jawahar Thomas Johnsingh, who deposited the paratype in the collection of Bombay Natural History Society and has made numerous valuable contributions to natural history studies in India

Ecology and distribution. The holotype was observed at a height of ca. 10 m on a tamarind tree ( Tamarindus indicus ) in riparian habitat. Five other individuals were observed on five different trees. All were at heights of ca. 3/ 4 of the tree’s height. The highest trees in this habitat were ca. 15– 20m. All individuals tried to escape into tree holes when approached. Two of them, including the paratype, were basking on branches (10 and 13 m height), ca. 0 900 h and three of them were near tree holes, ca. 10, 8 and 13 m heights at ca. 1500 h. In August 1983, Ajai Desai of Bombay Natural History Society captured an individual of the species from a Vitex leucoxylon tree, but it escaped ( Vickram & Johnsingh 1985). A colour photograph of this individual was printed in page 156 of Johnsingh (2006). In May 1985, the paratype was found when it fell from a tree, and when it was chased, it hurriedly burrowed in the sand in a riverine forest along Tamaraparani River ( Vickram & Johnsingh 1985). It was collected and identified as D. haliana by Aloysius Gnana Shekar of Bombay Natural History Society ( Vickram & Johnsingh 1985). All the individuals of D. johnsinghi sp. nov. described here were found inside Kalakkad–Mundanthurai Tiger Reserve located in the southern Western Ghats.

Comparison with congeners. The new species is easily distinguished from all the other species inhabiting Southeast Asia ( D. olivacea , D. nicobarensis , D. grisea , D. griffini and D. semicincta ) by its lower midbody scale count (22–24 versus over 28 in all species inhabiting Southeast Asia) and its distinctive colour pattern. From D. subcaeruleum it is distinguished by having keeled posterior dorsal scales (smooth in D. subcaeruleum ); black cross-bands on the body (no cross-bands on body in D. subcaeruleum ); 22–24 scales around body (vs. 26–28 in D.

subcaeruleum ). The new species is most similar to D. haliana , which occurs in Sri Lanka. From D. haliana , it is distinguished by the following characters: posterior genials more separated from each other than in D. haliana ; a large anterior temporal in contact with the parietal and last two supralabials (temporal not touching parietal in D. haliana ); presence of a projecting flap-like scale on the anterior wall of the ear opening (no projecting scale in D. haliana ); dorsal black stripes starting on the head extending to the level of 13th vertebral scale (dorsal black stripes on head extending only to the level of the nuchals where they join each other to form a broken collar in D. haliana ); no black cross-bands on the neck (black cross-band on neck in D. haliana ); black cross-bands on body spotted with white (no white spots on black cross-bands in D. haliana ). The distinctive characters of South Indian and Sri Lankan species are listed in Table 2 .

Tables

TABLE 1. Morphometric measurements of Dasia johnsinghi sp. nov. and Dasia subcaeruleum. Abbreviations used are listed in the Materials and methods.

Morphometric characters (in Dasia johnsinghi sp. nov. mm) Holotype ZSIC 25946	Dasia johnsinghi sp. nov. Paratype BNHS 1391	Dasia subcaeruleum ZSIC 25945
SVL 91.2	86.3	64.3
TaL 86.0	88.1	--
HL 14.4	17.2	10.7
HW 12.4	13.1	9.1
AG 45.0	44.5	31.8
SO 7.5	6.8	5.9
NO 5.3	4.6	3.5
ED 3.2	4.3	3.1
ET 7.3	6.6	5.2

TABLE 2. Morphological differences between species of South Asian Dasia.

Morphological characters	Dasia johnsinghi sp. nov. Dasia haliana	Dasia subcaeruleum
Posterior genials	Widely separated Just separated	Just separated
Temporal scales	1st temporal touching suprala- 1st temporal not in contact bial and parietal with parietal	1st temporal not in contact with parietal
Lamellae under 4th toe	17–18 16–17	14–16
Dorsal body scales	22–24 22–24	26–28
Vertebral scales	Enlarged Enlarged	Not enlarged
Posterior dorsal scales	2 or 3 keels 2–4 keels	Smooth
Scales on hind limbs	2 or 3 keels 2–4 keels	Smooth
Tubercles on heels	5 4–6	10
Dorsal head stripe	Starts on 3rd supraocular Starts on 2nd supraocular	Starts on 2nd supraocular
Length of dorsal head stripe	Reaches 12–13th dorsal scale Ends at the nuchal scales row	Reaches 14–15th dorsal scale row
Lateral head stripe	Reaches as far as the dorsal stripe Ends before tympanum	Reaches as far as the dorsal stripe
Nuchal collar	Absent Present	Absent
Cross-bands on neck	Absent 3.5 scales wide	Absent
Cross-bands on body	7, each one scale wide 5, each 3–4 scales wide	Absent
Colour of cross-bands	Black; each scale with a white Black spot	Absent