Cyrtodactylus guwahatiensis, Agarwal & Mahony & Giri & Chaitanya & Bauer, 2018

Agarwal, Ishan, Mahony, Stephen, Giri, Varad B., Chaitanya, R. & Bauer, Aaron M., 2018, Six new Cyrtodactylus (Squamata: Gekkonidae) from northeast India, Zootaxa 4524 (5), pp. 501-535 : 503-509

Cyrtodactylus guwahatiensis sp. nov.

Figs. 3–5 .

Holotype. Adult male ( BNHS 2146 , field number CES09/1127), collected from Hengrabari Road , Guwahati City , Kamrup Metropolitan district, Assam state, India (26.16193°N, 91.78298°E, elevation <100 m asl.) by Ishan Agarwal, 11 June 2009.

Diagnosis. Cyrtodactylus guwahatiensis sp. nov. can be distinguished from all congeners by: its moderate body size (SVL up to at least 67.8 mm); 10 supralabials; nine infralabials; 23 or 24 longitudinal rows of bluntly conical, feebly keeled dorsal tubercles; tubercles extending till third segment of tail; 35 paravertebral tubercles; ~34 ventral scales between ventrolateral folds; no precloacal groove; 26 precloacofemoral pores in a discontinuous series interspersed by 11 unpored scales; a row of enlarged scales above and below precloacal pore-bearing scales, slightly larger than pore-bearing scales; 16 total subdigital lamellae beneath toe IV of pes; subcaudal scalation of original tail without enlarged plates; dorsal pattern of 8–10 transverse rows of two or three pale buff blotches outlined by thick dark reticulations. Tail with alternating dark and lighter bands.

Etymology. The specific epithet is a toponym for the type locality of the species, Guwahati, the largest city in Assam and northeast India.

Description of holotype. Holotype in generally good preservation condition except folds on abdomen, head bent towards right, tail tip removed as tissue voucher, constriction just anterior to hind limb insertion due to overzealous tag tying. Adult male, SVL 67.8 mm. Head long (HL/SVL 0.26; HW/HL 0.67), dorsoventrally depressed (HD/HW 0.58), distinct from neck; loreal region somewhat inflated, interorbital area flat, canthus rostralis not prominent; snout short (SE/HL 0.43), twice as long as orbit diameter (ED/SE 0.51); scales on forehead, canthus rostralis and snout homogeneous, those on forehead smaller, roughly hexagonal, juxtaposed, weakly pointed; scales on interorbital and occipital region heterogeneous, granular, intermixed with larger, rounded, conical tubercles which are two to three times larger than adjacent granules, enlarged tubercles sparse on interorbital region and dense on occiput, single row of enlarged pointed tubercles on the eyelids, one or two scale rows from supraciliaries on each side. Eye small (ED/HL 0.22); pupil vertical with crenulated margins; supraciliaries small, mucronate, decreasing in size towards posterior and anterior end of orbit, largest about onethird the way from anterior edge of orbit; ear opening oval, obliquely oriented; eye to ear distance approximately half eye diameter (ED/SE 0.51). Rostral wider (2.7 mm) than deep (1.7 mm), partially divided dorsally by weakly developed rostral groove; single much enlarged supranasal on either side, separated by single small internasal, approximately same size as enlarged scales on snout; rostral in contact with supralabials I, nostrils, supranasals and an internasal; nostrils semicircular, laterally oriented, posterior half covered by nasal pad, each in broad contact with rostral and surrounded by supranasal, supralabial I, and 3–4 postnasals; three or four rows of scales separate orbit from supralabials; mental wider (2.3 mm) than long (2.0 mm), triangular, two well-developed postmentals on either side, inner pair in broad contact (1.2 mm) behind mental, twice the size (2.1 mm) of and separating outer pair (1.0 mm); inner postmentals bordered by mental, infralabial I, outer postmental and eight gular scales; outer postmental bordered by inner postmental, infralabials I and II, and five gular scales of dissimilar sizes on either side; eight supralabials to midorbital position and 10 supralabials to angle of jaw on each side, bordered by a row of large, flat, keeled, elongate scales; nine infralabials on each side, infralabials II to VI bordered by one or two rows of enlarged scales, increasing in size anteriorly.

Body slender, short (TRL/SVL 0.47) with ventrolateral folds; dorsal scales heterogeneous, mostly rounded granules, intermixed with irregularly arranged, enlarged tubercles, bluntly conical and keeled throughout, becoming more conical and slightly smaller towards flanks, ventrolateral folds with single row of scattered enlarged, smooth tubercles; tubercles extend from occipital region posteriorly onto tail base; tubercles on nape smaller than those of dorsum; enlarged tubercles on tail flat, weakly pointed and feebly keeled; 23 or 24 dorsal tubercles across mid-dorsum; 35 paravertebral tubercles; ventral scales much larger than dorsals, smooth, cycloid, imbricate to subimbricate; slightly smaller in size under thighs, two rows of enlarged scales between precloacal pores and vent; ~34 ventral scales between ventrolateral tubercle rows; gular region with small granular scales throughout except a few anterior scales bordering the postmentals that are larger, juxtaposed. Eleven distinct porebearing precloacal scales in a continuous series, separated on each side by one unpored scale from a discontinuous series of smaller pore-bearing femoral scales; six femoral pores on the right and nine on the left with five and four unpored scales in each series, respectively; no precloacal groove; hemipenal bulge distinct.

Fore and hind limbs slender, short (FL/SVL 0.14, CL/SVL 0.16); digits short, strongly inflected at each joint, all bearing robust recurved claws; five subdigital lamellae in basal series and nine in distal series with two nonlamellar granules at inflection (digit IV, right manus); seven basal and nine distal lamellae with three non-lamellar granules at inflection (digit IV, right pes), inter-digital webbing absent on manus, rudimentary between toes I to IV; relative length of digits: I <II <V <III <IV (right manus) and I <II <III <V <IV (right pes); scales on palms and soles smooth, flat, subimbricate; scales on fore limbs heterogeneous, composed of flat, weakly pointed, feebly keeled, subimbricate scales on upper arms, those on forearms heterogeneous, granular close to elbows with slightly enlarged tubercles, becoming flat, smooth and subimbricate anteriorly, ventral portion covered with small granular scales; scales on hind limbs heterogeneous, dorsal part of thighs and shanks with larger, conical granular scales, intermixed with scattered, enlarged, conical, feebly keeled tubercles; anterior portion of thighs and ventral aspect of hind limbs with much enlarged, smooth, imbricate scales.

Tail original, incomplete, rounded, slender, tapering; divided into indistinct caudal segments; two to three rows of enlarged, flat, weakly pointed, smooth, tubercles positioned transversely on first three segments of tail, remaining dorsal caudal scales smooth, rounded, subimbricate, similar in size dorsally but becoming larger on lateral aspect; subcaudal scales larger, smooth, imbricate and heterogeneous in size, no enlarged plates. Three enlarged, smooth, conical post cloacal spurs on each side of tail base.

Colouration in life ( Fig. 3 ) Dorsal ground colour of body, limbs and tail dark-brown, head brown; top of head with indistinct light yellow blotches forming larger indistinct paired markings on occiput; labials lighter than dorsum of head; two light yellow narrow postorbital streaks not extending as far as ear opening; neck with pair of light tan spots, 8–10 transverse rows of two or three indistinct pale buff coloured blotches outlined by thick dark reticulations extending from above fore limb insertions to tail base, mid-dorsal line confluent with central light spots; limbs with indistinct crossbars and a few lighter blotches; eight dark and seven light caudal bands, dark bands approximately twice as wide as light bands; iris grey-silver with dark reticulations, pupil bordered by brown.

Colouration in preservative ( Figs. 4 & 5 ). Dorsal ground colour of body, limbs and tail light-brown, head brown; top of head with indistinct light blotches forming larger indistinct paired markings on occiput; labials similar in shade to dorsum of head; two light narrow postorbital streaks not extending as far as ear opening; neck with pair of light tan spots, 8–10 transverse rows of two or three indistinct pale buff coloured blotches outlined by thick dark reticulations extending from above fore limb insertions to tail base, mid-dorsal line confluent with central light spots; limbs with indistinct crossbars and a few lighter blotches; eight dark and seven light caudal bands, dark bands approximately twice as wide as light bands.

Distribution and Natural History. This species is only known from a degraded moist deciduous forest on a small hill, completely surrounded by the urban sprawl of Guwahati, Assam. The holotype and only known specimen was collected near a seepage on a muddy wall along a hill road about 1.5 hours after sunset.

Comparisons. Cyrtodactylus guwahatiensis sp. nov. is a member of the lowland clade and is sister to C. septentrionalis sp. nov., the clade also including C. ayeyarwadyensis , C. tripuraensis , C. khasiensis and C. kazirangaensis sp. nov. The p- distance analysis demonstrated that the ND2 gene of the new species is 11.3% divergent from that of C. septentrionalis sp. nov. and 13.0–19.7% divergent from others in the clade ( Table 2). Cyrtodactylus guwahatiensis sp. nov. can be diagnosed by the total number of precloacofemoral pores (26 PcFP) on males from C. khasiensis (10–12 PcP) and C. tripuraensis (29–37 PcFP); further differs from C. tripuraensis by having slightly more DTR (23 or 24) and fewer MVSR (34) vs. (19̚21 DTR, 35–43 MVSR). The new species differs in colouration from C. ayeyarwadyensis (no white punctuations or narrow band following dark dorsal markings) Cyrtodactylus guwahatiensis sp. nov. is diagnosed from C. kazirangaensis sp. nov. and C. septentrionalis sp. nov. after the descriptions of the latter two species. Major diagnostic characters for the new species and other regional congeners are summarized in Table 3.

Figures

FIGURE 3. Cyrtodactylus guwahatiensis sp. nov. in life (adult male holotype, BNHS 2146).

FIGURE 4. Dorsal view (A), ventral view (B), and details of dorsal pholidosis (C) of adult male holotype (BNHS 2146) of Cyrtodactylus guwahatiensis sp. nov. Scale bars 10 mm.

FIGURE 5. Head of Cyrtodactylus guwahatiensis sp. nov. (adult male holotype, BNHS 2146), dorsal (A), lateral (B), and ventral (C) view. Scale bars 10 mm.