Dasia subcaeruleum Boulenger 1891, sp. nov.
Creators: name: Vasudevan, Karthikeyan
name: Silva, Anslem De
name: Kar, Niladri Bhusan
name: Naniwadekar, Rohit
name: Lalremruata, Albert
name: Prasoona, Rebekah
name: Aggarwal, Ramesh K
Publisher: name: Zenodo
Year: 2012
Subjects: Biodiversity
Taxonomy

description: Redescription of Dasia subcaeruleum (Boulenger, 1891)
Suggested common English name: Boulenger’s tree skink
Dasia subcaerulea Smith, 1935, 1949
Dasia subcaeruleum Das, 1996
Holotype. BM 1946.8.15.55 from Bodinaikanur, presently in Madurai district, Tamil Nadu, India at an altitude of 1,100 feet (ca. 335 m asl)
Paratype. BMNH 1949.1.8.51 collected by Angus F. Hutton from High Wavy Mountains, Madurai district, Tamil Nadu State, India at an altitude of 5,700 feet (ca. 1,700 m asl).
Diagnosis. Specimen is placed in genus Dasia Gray, 1839 by a combination of following characters: palatal notch not extending forwards to between the front of the eyes; eyelids being well developed; lower eyelid scaly; nostril in the nasal; supranasal present; prefrontals, frontoparietals and interparietal being distinct; ear opening small and tympanum sunk. A relatively small and slender species of the genus, characterized by feebly keeled dorsal scales on posterior body, 28 scale rows around the body; 14–16 lamellae under the fourth toe.
The redescription is based on a new specimen, and the details of which are as follows: ZSIC 25945; male collected by M. S. Chaitra, on 19 November 2005, from Singsar game road (elevation 750 m asl), Kudremukh Range (latitude N 13.21339°, longitude E 75.18583°; WGS 84 datum), Kudremukh National Park, Karnataka State, India.
Redescription. A small sized skink (SVL 64.3 mm); head longer than broad (HL/HW ratio 1.17); snout pointed; rostral broad, wider than high; a pair of separated internasals, almost as long as nasals; a rhomboid frontonasal, wider than long, and in contact with anterior loreal scale; a pair of prefrontals not in contact with each other; prefrontals medially in contact with frontonasal, anterior and posterior loreals, first supraciliary, first supraocular and frontal; frontal lanceolate (divided in our specimen); a pair of frontoparietals in contact with each other; frontoparietals in contact with frontal, 2nd, 3rd and 4th supraoculars, parietal and interparietal; interparietal lanceolate and barely separated from nuchals; four supraoculars, second one largest; the second supraocular is posterior most supraocular in contact with frontal (Greer & Broadley 2000); eight supraciliaries, first one largest; nostril in the middle of the nasal; a single postnasal present only on the left side; two loreals, anterior and posterior loreals longer than high; lower eyelid scaly; eight supralabials on right side and seven on the left side; sixth supralabial largest and in contact with the eye on the right side while fifth is largest and in contact with the eye on the left side; seven infralabials on both the sides; three pretemporal scales and three temporal scales; temporal scales imbricate, smooth and cycloid; ear opening elliptical and small; a single post mental scale and two pairs of chin shields; the anterior pair in contact with each other; posterior pair separated by a scale; gular scales similar to ventrals in size; a pair of wide nuchal scales; the neck scales are smaller laterally; dorsal scales cycloid, imbricate and almost smooth anteriorly; posterior body scales very feebly keeled, almost smooth; ventrals similar to dorsals; no distinct boundary between dorsals, laterals and ventrals; 52 vertebral scales, not enlarged; 54 ventral scales; 26 scales around the mid–body; a pair of enlarged preanal scales; fore- and hind limbs touch each other when adpressed against the body; palms covered in slightly enlarged tubercles with approximately 10 enlarged tubercles on the heels; toe length in the following order 1 <2 <5 ≈ 3 <4; 16 lamellae under the fourth toe.
Variation in new specimen. The specimen ZSIC 25945 was asymmetrical in the number of supralabials on each side; the right side had eight while the left side had seven supralabials. Also the post nasal was absent on the right side but present on the left side. In this case the prefrontals were well separated from one another. Thus, it shows that both the characters (number of supralabials and prefrontals in contact with one another) could not be used to differentiate this species. It had 26 scale rows around the body, compared to 28 in the holotype.
Wickramasinghe et al. (2011) used the paratype of D. johnsighi sp. nov. to redescribe D. subcaeruleum, overlooking the fact that the D. subcaeruleum holotype had a count of 28 midbody scale rows whereas, the specimen they used had only 24. They have overlooked: (i) the smooth nature of dorsal scales in D. subcaeruleum; (ii) the scattered black and white spots in the type of D. subcaeruleum, and no dorsal cross-bars as seen in D. johnsinghi sp. nov.
Colouration in life. Dorsum was grayish brown. There was a dark stripe extending from rostral to eye and then going beyond the eye to the front of the shoulder (fig. 5). Posterior to the eye, the edges of the stripe are dark. Two distinct broad stripes extended from the second supraocular to behind the neck. The dark bands are approximately two scales wide on the torso. There was a series of black spots along the lateral side of the body extending from the forelimbs to the tail and then going further down the tail. Belly colour is pale bluish. Rostral, supralabials, infralabials and mental are light yellow in color. Palm and sole are brown in color. Both the presence of blue color on the belly and the two bands extending from the head to nape are similar as in the holotype.
Distribution. The holotype (fig. 6) was collected from Bodinaikanur (Boulenger 1891) and the paratype was collected from High Wavy Hills (Smith 1949), both presently in Madurai district of State of Tamil Nadu. Although the two locations are in southern Western Ghats and not far from each other, there is an altitudinal difference of about 1,400 m between the two. The present specimen is from Kudremukh National Park, situated in the state of Karnataka, in the central Western Ghats. This greatly extends the known range of this species, as the current locality is ca. 450 km north of the previous collection localities (fig. 1). This specimen was collected from middle elevations (ca. 750 m asl). Among the congeners, D. olivacea occupies riverine forests, coconut plantations and coastal forests in Southeast Asia (Grismer et al. 2001, 2004; Escobar et al. 2003). D. grisea is found throughout the Sunda Shelf and the Philippines (Brown & Alcala 1980), where it too occupies riverine forests (Brown et al. 2000). D. nicobarensis is found in the coastal lowland forests of the Nicobar Islands, and are common in coconut plantations (Das 1999; Pers. Obs.). D. subcaeruleum is the only species that occupies evergreen forest at high elevations> 750 m asl adjoining grasslands. When compared the other species that were associated with riparian forest or costal low land forest, D. subcaeruleum contrasts in its distribution and habitat use.
Comparison with congeners. D. subcaeruleum can be distinguished from all other congeners by a combination of characters; body scales nearly smooth, 26–28 in number around the mid-body; 14–16 lamellae on the fourth toe; a pattern of two black dorsal stripes running from second supraocular to behind the shoulder. From D. haliana and D. johnsinghi sp. nov., it is easily distinguished by its higher mid-body scale count (26–28 as opposed to 22–24 in the other two species) and its relatively smooth posterior dorsal scales.
description: Published as part of 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, pp. 37-51 in Zootaxa 3233 on pages 44-46, DOI: 10.5281/zenodo.211627