Cyrtodactylus septentrionalis, 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 : 514-517

Cyrtodactylus septentrionalis sp. nov.

Figs. 9–11 .

Holotype. Adult female ( BNHS 1990 ), collected from near Abhayapuri town , Bongaigaon district , Assam state, India (26.345417°N, 90.677875°E, 40 m asl.) by Varad Giri and Kedar Bhide on 13 November 2009.

Paratype. Adult male ( BNHS 1989 ), bears the same collection details as holotype .

Etymology. The specific epithet is a nominative, masculine, singular, Latin adjective meaning “northern”, as this species is the only known member of the lowland clade ( Agarwal et al. 2014) that is found north of the Brahmaputra River, the other five known species of the clade are found south of the Brahmaputra River.

Diagnosis. Cyrtodactylus septentrionalis sp. nov. can be distinguished from all congeners by its moderate body size (SVL to at least 65.2 mm); nine or 10 supralabials; nine infralabials; 23 or 24 longitudinal rows of bluntly conical, feebly keeled dorsal tubercles; tubercles extend onto first three tail segments; 38–42 paravertebral tubercles; 35–38 ventral scales between ventrolateral folds; no precloacal groove; 14 fine precloacal pores and no femoral pores on males; 15–20 total subdigital lamellae beneath toe IV of pes; subcaudal scalation of original tail without enlarged plates; dorsal colour pattern of 6–9 rows of paired dark blotches, tail with alternating dark and lighter bands.

Description of holotype. Holotype generally in good preservation condition: trunk curved to left, folds of skin along either side of ventrolateral aspect, constriction just anterior to hind limb insertion due to overzealous tag tying. Adult female, SVL 65.2 mm. Head long (HL/SVL 0.30), slightly wide (HW/HL 0.70), not depressed (HD/ HW 0.63), distinct from neck; loreal region somewhat inflated, interorbital region flat, canthus rostralis not prominent; snout short (SE/HL 0.50), twice as long as orbital diameter (ED/SE 0.50); scales on snout and canthus rostralis granular, juxtaposed, homogenous in shape with scales on dorsum of snout being slightly larger; scales on interorbital region, forehead and occipital region slightly smaller, granular, juxtaposed; forehead sparsely and occipital region densely interspersed with larger tubercles that are rounded, smooth, and two times the size of adjacent granules. Eye small (ED/HL 0.20); pupil vertical with crenulated margins; supraciliaries flat, smooth, roughly triangular, decreasing in size towards posterior and anterior ends of orbit, largest about one-third the way from anterior edge of orbit; a single row of enlarged tubercles bordering supraciliaries present on dorsal surface of upper eyelid. Ear opening oval, obliquely oriented, large. Eye to ear distance slightly larger than diameter of eye (ED/EE 0.70). Rostral wider (2.7 mm) than deep (1.7 mm), divided dorsally by a weakly developed rostral groove; single much enlarged rounded supranasal on either side, separated by two rows of three granular scales; rostral in contact with supralabials I, nostrils, supranasals and three scales separating supranasals; nostrils oval, laterally oriented, posterior half covered by a conspicuous nasal pad, each nostril in broad contact with rostral and surrounded by internasal, supralabial I, and four smaller, granular postnasal scales; three rows of granular scales separate orbit from supralabials; mental wider (2.3 mm) than deep (2.0 mm) triangular, two well-developed pairs of 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); each inner postmental bordered by mental, infralabial I, outer postmental and three gular scales, outermost of which is largest; outer postmentals bordered by inner postmentals, infralabials I and II, a large, roughly hexagonal scale posteriorly and four gular scales; seven supralabials to midorbital position on each side; supralabials to angle of jaw, nine on right side and 10 on left side, bordered by a row of flat, somewhat elongated scales slightly larger than adjacent granular scales; nine infralabials on each side, infralabials II–V bordered by one or two rows of enlarged scales, anteriormost largest.

Body slender (BW/TRL 0.4), short (TRL/SVL 0.40); dorsal scales heterogeneous with mostly rounded granules intermixed with irregularly arranged, enlarged tubercles that are rounded, slightly conical, feebly keeled; a distinct ventrolateral fold on either side with enlarged, rounded, flat tubercles interspersed by one or two slightly enlarged, flat, juxtaposed scales; tubercles extend from forehead posteriorly onto base of tail; tubercles on nape smaller than those of dorsum; 23 or 24 dorsal tubercles across mid-dorsum; 38 paravertebral tubercles; ventral scales much larger than dorsals, smooth, cycloid, juxtaposed; slightly smaller in size under thighs; a row of slightly enlarged, flat, subimbricate scales along posterior border of precloacal scales; 36–38 ventral scales between ventrolateral folds; gular region with small granular scales throughout, except for one or two rows originating from posterior margin of outer postmentals, bordering infralabials, which are larger, flat, juxtaposed. A continuous series of 14 indistinct depressions in precloacal scales, no pores, no precloacal groove.

Fore and hind limbs slender; forearm (FL/SVL 0.20) and tibia (CL/SVL 0.20) short; digits short, strongly inflected at each joint, all bearing robust recurved claws that are slightly longer than claw sheath; six subdigital lamellae in basal series and nine in distal series with three non-lamellar granules at inflection (digit IV, right manus); five basal and 10 distal lamellae with four non-lamellar granules at inflection (digit IV, right pes); slight inter-digital webbing between toes I–III, absent between fingers; 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, juxtaposed, with those on sole being slightly larger; scales on fore limbs heterogeneous, composed of large, granular, juxtaposed scales becoming flatter, smooth and subimbricate anteriorly, sparsely interspersed with slightly enlarged rounded, feebly keeled tubercles; ventral portion covered mostly with granular, rounded, juxtaposed scales; scales on hind limbs heterogeneous, with large, subimbricate, flat scales, scattered densely with rounded, enlarged, conical, strongly keeled tubercles; ventral aspect of hind limbs with enlarged, smooth, subimbricate scales.

Tail original with regenerated tip, somewhat rounded, slender, tapering, not divided into segments; about ten rows of enlarged, rounded, feebly keeled tubercles on tail base and 1–4 rows on the first three segments; remaining dorsal caudal scales smooth, roughly rectangular, subimbricate throughout without a single row of tubercles along the posterior edge of the first three segments; subcaudal scales larger, smooth, imbricate; no distinct mid-ventral series; three enlarged smooth post cloacal spurs on each side.

Colouration in life. Not documented.

Colouration in preservative ( Figs. 10 & 11 ). Dorsal ground colour of body, head, limbs and tail light brown; top of head scattered with few dark brown markings including longitudinal streak extending from occiput to nape; labials pale cream with fine black stippling; dark postorbital streak flanked by lighter markings that extend to ear openings, dark preorbital streak present extending to nostrils; neck with three longitudinal dark markings; dorsal pattern of six or seven pairs of dark elongated blotches from fore limb insertion to tail base; ventral surfaces immaculate; limbs with dark blotches; original portion of tail with eight dark and light markings that circle tail; regenerated portion of tail light brown, with a few dark spots.

Variation ( Fig. 9 ). BNHS 1989 is a male with 13 fine precloacal pores and nine pairs of dark dorsal markings; six dark and light markings on incomplete but original tail; broadly agreeing in scalation with the holotype ( Table 4) .

Distribution and Natural History. Cyrtodactylus septentrionalis sp. nov. is only known from the vicinity of Abhayapuri town, close to the base of Bamun Gaon Pahar (a small hill). Nine individuals of this species were observed during a single night of search. They were found on open rocks along a small stream running through degraded forest near a human settlement.

Comparisons. Cyrtodactylus septentrionalis sp. nov. is a member of the lowland clade and differs from other members of the clade by 11.3–18.6 % uncorrected genetic distance. Cyrtodactylus septentrionalis sp. nov. can be diagnosed by the presence of 14 precloacal pores and the absence of femoral pores on males from C. ayeyarwadyensis (10–28 PcP–PcFP), Cyrtodactylus guwahatiensis sp. nov. (26 PcFP in discontinuous series), Cyrtodactylus kazirangaensis sp. nov. (10 or 11 PcP), C. khasiensis (10–12 PcP), and C. tripuraensis (29–37 PcFP). Cyrtodactylus septentrionalis sp. nov. further differs from C. khasiensis in having more dorsal tubercle rows (23 or 24 vs. 19–23). Major diagnostic characters for the new species and regional congeners are summarized in Table 3.

Figures

FIGURE 9. Paratypes of the new species described in this paper. From left to right, top panel: Cyrtodactylus kazirangaensis sp. nov. (BNHS 2147, 2149), Cyrtodactylus jaintiaensis sp. nov. (BNHS 2246), Cyrtodactylus montanus sp. nov. (BNHS 2234), and Cyrtodactylus jaintiaensis sp. nov. (BNHS 2247); bottom panel: Cyrtodactylus nagalandensis sp. nov. (BNHS 2254), Cyrtodactylus septentrionalis sp. nov. (BNHS 1989), and Cyrtodactylus montanus sp. nov. (BNHS 2231–2233).

FIGURE 10. Dorsal view (A), ventral view (B), and details of dorsal pholidosis (C) of adult female holotype (BNHS 1990) of Cyrtodactylus septentrionalis sp. nov. Scale bars 10 mm.

FIGURE 11. Head of Cyrtodactylus septentrionalis sp. nov. (adult female holotype, BNHS 1990), dorsal (A), lateral (B), and ventral (C) view. Scale bars 10 mm.