Calotes sinyik Patel, Thackeray, Sheth, Khandekar & Agarwal, 2024, sp. nov.

Calotes sinyik sp. nov. urn:lsid:zoobank.org:act: 4EAFC175-AE18-4A92-B9E5-DA1CAB1D607F (Figures 3, 4A–C, 5A, 6A, 7A, 8) Holotype. NRC-AA-8424 (AP 078), adult female, from near Lingbuk Riamukh (28.26210°N, 94.15900°E; ca. 1270 m asl.), Payeng Circle, Upper Subansiri District, Arunachal Pradesh, India; collected by Harshil Patel, Ishan Agarwal and Chintan Sheth on 7 th October 2023. Paratype. NRC-AA-8425 (AP 077), juvenile, same collection data as holotype except (28.26868°N, 94.1590°E). Etymology. The specific epithet is the local name of the Subansiri River in the Tagin language, used as a noun in apposition. The Tagin are one of the major tribes of Arunachal Pradesh and mainly inhabit Upper Subansiri District. Suggested common name is Sinyik or Subansiri dragon lizard. Agamids are commonly referred to as /sopin/ in Tagin. Diagnosis. A small-sized Calotes, snout to vent length up to 65 mm (n = 2). Body feebly compressed laterally with a weak dorsal crest; scales on top of head highly heterogeneous, keeled, those above orbit and surrounding parietal are among the largest in size; three spines on each side of head, a short one above orbit, one above tympanum and one on temporal region; dorsolateral scales of body heterogeneous in size, composed of medium-sized, weakly pointed, strongly keeled scales, intermixed with similar but slightly larger scales which are distinct on flanks, upper rows directed backwards and upwards and a few lower rows directed backwards; 54 or 55 midbody scale rows; 42 or 43 vertebral scales; a weakly developed antehumeral fold; tympanum very small in adult; tail rounded in crosssection; nine or 10 supralabials and 10–12 infralabials; lamellae bicarinate, 24 or 25 on fourth finger and 26–28 on fourth toe. Comparisons with regional congeners. The new species can be easily separated from all regional congeners except C. bhutanensis, C. paulus and C. zolaiking by its small body size (maximum SVL up to 65 mm versus 91– 158 mm) and from all regional congeners except C. paulus and C. zolaiking by the presence of heterogeneous scales on the dorsolateral aspect of body, a weakly developed antehumeral fold, and a weakly developed dorsal crest. The new species is most similar to C. paulus and C. zolaiking but differs from both species with respect to the following: greater number of midbody scale rows (54 or 55 versus 42–46 in C. paulus and 49–52 in C. zolaiking), greater number of vertebral scales (42 or 43 versus 24–32 in C. paulus and 32–35 in C. zolaiking), and in dorsolateral scales of the body being heterogeneous only in size (versus dorsolateral scales of body heterogeneous in both size and shape in C. paulus and C. zolaiking) (see Figs. 5–7). Description of the holotype. An adult female in generally good condition except tail bent toward left in a sigmoid manner; left and right manus slightly adpressed with third and fourth fingers curved; second, third and fourth toe of the right pes curved; eyes sunken, orbital spine on left side and tips of temporal spines on both sides curved; a 7.8 mm long incision in sternal region for tissue collection (Fig. 3A, 3B)—all artefacts of preservation. Mensural and meristic data is summarised at the end of the description. SVL 64.6 mm, head relatively long (HL/ SVL 0.33), broad (HW/HL 0.71), not depressed (HD/HL 0.55), noticeably broader than neck (Fig. 4A, 4B). Snout short (SE/HL 0.39), longer than orbit diameter (OD/SE 0.67). Orbit large (OD/HL 0.26); pupil round, eyelids covered with small rounded scales, a single row of scales bordering eyelids slightly elongate, eight supraciliaries on each side, slightly elongate, subimbricate, slightly protruding laterally on supraorbital ridge, similar in size. Snout obtusely pointed; rostral wider (2.3 mm) than deep (1.1 mm), contacted laterally by first supralabial, an elongated large prenasal, and two large scales dorsally. Canthus rostralis and supraciliary edge sharp. Nostril circular, oriented slightly downwards, laterally positioned and placed at centre of a large, undivided, protrudent nasal plate (Fig. 4C), which is bordered by eight scales on both sides, including one prenasal, two supranasal, three postnasals, and two subnasals on both sides; separated on both sides from rostral and first supralabial by prenasal and first subnasal. Supralabials ten, roughly rectangular, more or less equal sized, posterior most being longest. Supralabials separated from the border of orbit by three rows of scales at midorbital position; middle row distinctly enlarged consisting of equal sized, roughly rectangular scales; scales on lower and upper rows heterogeneous in shape and size. Loreal region concave, scales of loreal region heterogeneous in shape and size, weakly tuberculate. Scales on postorbital and temporal region heterogeneous in shape and size, subimbricate, tuberculate; a row of four much larger longitudinally keeled scales, second longest and first widest, extending from posterior midorbital region to just before scales bordering the supra-tympanic spine (Fig. 4C). Tympanum small in size (TD 1.1 mm), covered with a single scale (Fig. 4C). Canthal scales enlarged, overlapping, keeled or weakly tuberculate, becoming slightly larger along supraciliaries. Scales on dorsal surface of snout and forehead heterogeneous in shape and size (Fig. 4A), smaller scales weakly tuberculate, larger with distinct keels except those on internarial region which are roughly rounded, uniformly large and weakly tuberculate. Supraorbitals increase in size from supraciliaries to inner edge of orbit, of which enlarged scales follow curvature of orbits posterolaterally, larger scales are keeled and smaller scales tuberculate with one or two tubercles on each scale, forming two or three rows adjacent to supraciliaries (Fig. 4A). Two small scale rows divide enlarged scales of inner orbits at narrowest point of frontal. Scales on occipital region heterogeneous in shape and size; smaller scales weakly tuberculate, larger ones with keels. Parietal scale roughly rectangular, with a pineal eye (Fig. 4A). Parietal scale bordered laterally by two or three enlarged, roughly elongated keeled scales, with much smaller scales anteriorly and posteriorly. Single temporal spine on each side, as long as the nuchal spines; very short orbital spine and a supra-tympanic spine, as long as the temporal spine, also present on each side (Figs. 4A, 4C). Mental subtriangular, wider (1.8 mm) than long (1.3 mm), bordered posterolaterally by a row of five elongated postmental chin shields on either side, gradually changing shape and size posteriorly to blend with surrounding rows of gular scales (Fig. 4B). Infralabials roughly rectangular, more or less similar in size, posterior most being largest, ten on the left side and 11 on the right side. First pair of postmental chin shields in contact laterally with first infralabials, remaining shields separated from infralabials by one or two rows of small gular scales. Posterior gular region with considerably enlarged, flat, strongly keeled, pointed, imbricate scales, those on jowls slightly larger in size; anterior gular scales smaller, rounded, weakly keeled and subimbricate; all gular scales directed posteromedially except a few median rows which are directed posteriorly. No distinct gular pouch present, transverse gular fold absent (Fig. 4B). Ventral scales similar to those on posterior gular region, enlarged, flat, strongly keeled, pointed, imbricate, homogenous in shape but heterogeneous in size, generally increasing in size laterally; arranged in regular longitudinal rows that are directed posteriorly, those on lateral aspect are directed posteromedially (Figs. 6A, 7A). Approximately 55 scales around midbody. Nuchal crest most prominent on neck, composed of nine or ten long, erect, laterally compressed, spines; remaining scales in vertebral row slightly enlarged relative to adjacent dorsal scale rows, much more flattened than spines in the nuchal crest (Fig. 4C) but with a pronounced median keel providing a serrated appearance in profile (Fig. 6A); 43 middorsal scales from first raised nuchal scale to above level of cloaca. Dorsal scales rectangular, heterogeneous in size on dorsolateral aspect; all scales with a moderate median keel, slightly pointed, roughly arranged in transverse rows (Figs. 5A, 6A); keels on those of upper flanks mostly oriented obliquely upward, horizontal or obliquely upward on midflanks and horizontal on lower flanks (Fig. 6A); scales bordering middorsal vertebral scales pointed with weak keels. A shallow oblique skin fold in front, and curving around anterior forelimb insertion. Scales of forelimbs and ventral hindlimbs form approximate rows, those on dorsal hindlimbs do not form regular rows and are heterogeneous in size. Dorsal scales larger than ventral scales on forelimbs and hindlimbs, all moderately keeled dorsally, very weakly keeled ventrally, scales on the posterior side of the thigh much smaller, weekly keeled and pointed. Forelimbs long ((UAL +LAL+HaL)/SVL 0.55); hindlimbs considerably long ((ULL+LLL+FoL)/SVL 0.82). Digits slender, elongate and ending in a strong, slightly curved claw. Lamellae entire, bicarinate; 25 on fourth finger, 28 on fourth toe. Relative finger lengths in mm: IV (10.1)> III (9.5)> II (7.4)> V (5.9)> I (4.6) and relative toe lengths: IV (14.3)> III (11.2)> V (8.7)> II (7.4)> I (4.9). Tail entire, rounded, more than twice head-body length (TL/SVL 2.35), not swollen at base (Figs. 3A, 3B); uniformly covered with similar sized, strongly keeled, weakly pointed, regularly arranged, posteriorly directed imbricate scales, except for the tip, which is covered with six rows of small, strongly keeled, laterally compressed, erected scales. Mensural (in mm) and meristic data for the holotype: SVL 64.6; TrL 29.5; TL 152; TaD 6.1; TW 7.6; HL 21.2; HW 15.1; HD 11.6; SE 8.3; NE 4.4; EE 5.7; IO 9.5; SFI 23.4; UAL 11.0; LAL 11.1; HaL 13.3; 4FL 10.1; ULL 14.1; LLL 16.1; FOL