Calotes sinyik, Patel & Thackeray & Sheth & Khandekar & Agarwal, 2024

Patel, Harshil, Thackeray, Tejas, Sheth, Chintan, Khandekar, Akshay & Agarwal, Ishan, 2024, A new small-sized Calotes Cuvier (Squamata: Agamidae: Draconinae) from the Subansiri river basin, Arunachal Pradesh, India, Zootaxa 5523 (2), pp. 151-170 : 156-166

publication ID	https://doi.org/ 10.11646/zootaxa.5523.2.1
publication LSID	lsid:zoobank.org:pub:E032D32F-0F67-45D6-901B-704E79D1EB10
DOI	https://doi.org/10.5281/zenodo.13970710
persistent identifier	https://treatment.plazi.org/id/4EAFC175-AE18-4A92-B9E5-DA1CAB1D607F
taxon LSID	lsid:zoobank.org:act:4EAFC175-AE18-4A92-B9E5-DA1CAB1D607F
treatment provided by	Plazi
scientific name	Calotes sinyik
status	sp. nov.

Treatment

Calotes sinyik sp. nov.

urn:lsid:zoobank.org:act:4EAFC175-AE18-4A92-B9E5-DA1CAB1D607F

( Figures 3 View FIGURE 3 , 4A–C View FIGURE 4 , 5A View FIGURE 5 , 6A View FIGURE 6 , 7A View FIGURE 7 , 8 View FIGURE 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. GoogleMaps

Paratype. NRC-AA-8425 (AP 077), juvenile, same collection data as holotype except (28.26868°N, 94.1590°E) GoogleMaps .

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 View FIGURE 5 View FIGURE 6 View FIGURE 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 View FIGURE 3 )—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 View FIGURE 4 ). 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 View FIGURE 4 ), 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 View FIGURE 4 ). Tympanum small in size (TD 1.1 mm), covered with a single scale ( Fig. 4C View FIGURE 4 ). 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 View FIGURE 4 ), 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 View FIGURE 4 ). 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 View FIGURE 4 ). 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 View FIGURE 4 ). 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 View FIGURE 4 ). 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 View FIGURE 4 ). 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 View FIGURE 6 , 7A View FIGURE 7 ). 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 View FIGURE 4 ) but with a pronounced median keel providing a serrated appearance in profile ( Fig. 6A View FIGURE 6 ); 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 View FIGURE 5 , 6A View FIGURE 6 ); keels on those of upper flanks mostly oriented obliquely upward, horizontal or obliquely upward on midflanks and horizontal on lower flanks ( Fig. 6A View FIGURE 6 ); 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 View FIGURE 3 ); 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 View Materials ; UAL 11.0; LAL 11.1; HaL 13.3; 4FL 10.1; ULL 14.1 ; LLL 16.1; FOL 23.3; 4TL 14.3; TD 1.1; OD 5.6; SnS 10; HeadSTr 13; CS 7 ; SL (L/ R) 10/10; IL (L/ R) 10/11; VS 43; MSR 55; 4Flam 25; 4TLam 28.

Coloration in life ( Fig. 8A, C View FIGURE 8 ). Coloration in life variable, primarily in mottled shades of light and darker brown with black variegation dorsally, tip of some scales on flank white, lower flanks lighter in colour. Forelimbs and hindlimbs darker than dorsum, with buff markings on the back side of upper arms and thighs, forelimbs with a whitish patch on the elbow. Region below orbit and lateral surface of snout and head with indistinct narrow light and dark brown radial stripes extending from eye, upper and lower lips greenish with white and brown mottling, eyelids light brown, orbital spine lemon green in colouration. Tail brown with faint light and darker brown bands. Venter with numerous dark brown or grey streaks and spots, a mid-ventral line runs from behind throat to above vent Ventral scales yellow on middle of throat and pectoral region; light brown from centre of belly to vent; sides of throat with dark variegations and orange scales; sides of belly light brown to grey with a light purple tinge. Several scales on the belly have a white tip. While photographing this individual it initially appeared dark greenish brown dorsally with green labials and the characteristic black or dark brown variegation. However, within a six seconds the lizard changed to a light brown shade with dark variegations and several seconds later to a dark brown colouration. This shows that the individual was capable of changing colour to suit its dark surroundings. The juvenile however, did not exhibit this behaviour.

Coloration in preservative ( Fig. 3A, 3B View FIGURE 3 ). Coloration in preservation more or less similar to colouration in life but faded and predominantly brownish with upper arm and thighs slightly bluish in shade. Transverse stripes on body, limbs and tail are darker than in life.

Variation ( Fig. 3C View FIGURE 3 , 8 View FIGURE 8 ). The paratype (juvenile, NRC-AA-8425), agrees with the holotype in general morphology and scalation with following exceptions: nine SL on both sides, IL 11 on the left side and 12 on the right side; 42 vertebral scales; approximately 54 scales around midbody; 24 lamellae under fourth finger and 26 under fourth toe; 11 scales between anterior supraciliaries. The live colouration is unlike the holotype with green, brown and blue coloured variegated markings on head and dorsum ( Fig. 8B View FIGURE 8 ). Dorsal scales light green or brown, brown scales have a fine brown peppering over a cream colour. Around nine brown stripes (1–3 scales broad) emerge radially from the orbit spaced apart by 1–4 scales. Scales from the upper labials to the sub-orbital edge are lime green with light edges. Dorso-anterior portion of the head mostly green with brown mottling, two dark greenish-brown stripes present on the dorsal scales of the head in line with the orbits. The distal portion of the head largely brown. Dorsal surface of the body has green, blue and brown scale colouration. Brown scales arranged in large blotches or diamonds spaced apart by one or two green or blue scales. This continues along the tail which is brown distally. A few dorsal scales are tipped white. An apical notch or pore present on all scales. Belly scales mostly cream coloured peppered with brown. Legs mostly with green and brown scales, except at the joint – forelimb joints with white scales and hindlimb joints with buff coloured scales. Further variation can be found in the mensural (in mm) and meristic characters in paratype documented here: SVL 26.5; TrL 9.9; TL 53.0; TaD 2.1; TW 2.1; HL 9.0; HW 6.8; HD 4.8; SE 3.7; NE 2.0; EE 2.7; IO 4.9; SFI 10.4; UAL 5.2; LAL 4.9; HaL 6.0; 4FL 4.5; ULL 5.7; LLL 5.9; FOL 9.6; 4TL 5.7; TD 0.7; OD 3.1; SnS 11; HeadSTr 13; CS 7.

Distribution and Natural History. Calotes sinyik sp. nov. is only known from the type locality near Lingbuk Riamukh in Upper Subansiri District at ~ 1270 m asl. ( Fig. 1 View FIGURE 1 ). The region has a temperate climate characterized by hot humid summers and cool to mild winters that is influenced by the southwest monsoon ( Kottek et al. 2006). Mean annual precipitation is ~ 1900 mm which is unequally distributed—precipitation of the driest quarter is only 42 mm and of the wettest quarter about 1000 mm ( Fick & Hijmans 2017). The mean temperature of the warmest quarter is 23°C and maximum temperature of the warmest month reaches about 27.6°C ( Fick & Hijmans 2017). The vegetation is largely recovering jhum (swidden or shifting cultivation areas that are periodically cleared of woody and shrubby vegetation for cultivation). The vegetation around these upland jhum habitats are not the typical sub-tropical evergreen or temperate broad-leaved forest vegetation that are observed in Western Arunachal ( Sheth 2021) but lies along a transition zone of these two comprising both sub-tropical evergreen and temperate broad-leaved vegetation types. Several species of bamboo (Bambusoideae), banana ( Musaceae ) and zingerables ( Zingiberaceae ), along with Eastern Himalayan Sago Palms ( Arecaceae - Arenga micrantha C. F. Wei ) were observed within the understorey indicating a long history of cultivation and food production by the indigenous Tagin tribe of the area (Blench 2012). The overstorey comprised large old-growth woody trees as well as recovering vegetation typical of regenerative jhum agricultural areas ( Fig. 9 View FIGURE 9 ). Lingbuk Riamukh is situated on the eastern side of the river Subansiri in a sub-basin of the Subansiri known as Sichi. The Sichi basin ranges from 320–4000m above sea level with a limited area lying within the 1200–1400m zone.

The holotype and paratype were collected <1 km apart on a single transect from ~1400–2030 hrs by three of us ( HP, CS, IA). Both lizards were spotted asleep at night, the holotype on a leafless twig and the paratype on a thin branch of a fallen dry tree, about 135–180 cm above the ground with the body roughly horizontally oriented and head directed slightly upwards. We did not record the new species at similar elevations immediately across the Subansiri River, nor were they observed further upstream or downstream from Lingbuk Riamukh. The only sympatric lizard we recorded at the type locality was Cyrtodactylus cayuensis Li on vegetation along road cuttings.