Cyrtodactylus montanus, 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 : 524-528

Cyrtodactylus montanus sp. nov.

Figs. 9 and 15–17

Holotype. Adult female ( BNHS 2235 , field number CES09/1215), collected from near Phuldungsei village in the southern Jampui Hills , Kanchanpur subdivision, North Tripura district, Tripura state, India (23.82257°N, 92.26034°E, 850 m asl.) by Tarun Khichi, N.P.I. Das, Aniruddha Datta-Roy and Ishan Agarwal on 3 November 2010.

Paratypes. Adult males ( BNHS 2232–2234 ) and an adult female ( BNHS 2231 ), bear the same collection data as the holotype .

Etymology. The specific epithet is a nominative, masculine, singular, Latin adjective meaning “pertaining to a mountain” as this species is a member of the mountain clade, and is restricted to a mountainous region in northwestern Tripura.

Diagnosis. Cyrtodactylus montanus sp. nov. can be distinguished from all congeners by its moderate body size (SVL to at least 78.2 mm); eight or 10 supralabials; 8–10 infralabials; 21–23 longitudinal rows of rounded, conical, feebly keeled dorsal tubercles; tubercles extending posteriorly to at least third tail segment; 37–43 paravertebral tubercles; 21–23 ventral scales between ventrolateral folds; no precloacal groove; 8–10 precloacal pores in males, no femoral pores; a row of enlarged scales posterior to precloacal pore-bearing scales, slightly larger than porebearing scales; 13–18 total subdigital lamellae beneath toe IV of pes; subcaudal scalation lacking enlarged median plates; dorsal colour pattern of thick dark reticulations enclosing lighter blotches; tail with alternating dark and lighter bands.

Description of holotype. Holotype in good preservation condition: tail tip removed for tissue voucher, toe V of pes missing, constriction just above hind limb insertion due to overzealous tag tying, small abrasion on gular region, and folds of skin on dorsal surface of head, all artefacts of preservation and storage. Adult female, SVL 58.8 mm. Head long (HL/SVL 0.28), slightly wide (HW/HL 0.66), dorsoventrally depressed (HD/HW 0.58), distinct from neck; loreal region inflated, interorbital region flat, canthus rostralis not prominent; snout short (SE/ HL 0.39), twice as long as orbital diameter (ED/SE 0.57); scales on snout and canthus rostralis, granular, juxtaposed, homogenous in shape with scales on snout being slightly larger; scales on interorbital region, forehead and occipital region slightly smaller, granular, juxtaposed; forehead and occipital region interspersed with larger tubercles that are rounded, smooth and two to four times size of adjacent granules; dense enlarged tubercles slightly smaller on forehead and larger on occipital region. Eye small (ED/HL 0.22); pupil broad, vertical with crenulated margins; supraciliaries only slightly larger than adjacent scales, weakly pointed; upper eyelids covered with small granular scales, row of enlarged tubercles bordering supraciliaries absent. Ear opening oval, obliquely oriented, large; eye to ear distance less than twice diameter of eye (ED/EE 0.69). Rostral wider (2.3 mm) than deep (1.1 mm), partially divided dorsally by a weakly developed rostral groove; single enlarged rounded supranasal on either side, separated from each other by two rows of two smaller granular internasal scales; rostral in contact with supralabials I, nostrils, supranasals and two small internasals separating supranasals; nostrils oval, laterally oriented, posterior half covered by a distinct nasal pad, each in broad contact with rostral and surrounded by supranasal, supralabial I, and five small granular postnasal scales; five rows of granular scales between mid-orbit and supralabials; mental wider (1.8 mm) than deep (1.2 mm), triangular, two well-developed postmentals on either side, inner pair in broad contact (1.4 mm) behind mental, twice as large (1.8 mm) and separating outer pair from each other (0.9); each inner postmental bordered by mental, infralabial I, outer postmental and a row of two or three gular scales; outer postmentals bordered by inner postmental, infralabial I and II, a large, roughly hexagonal scale posteriorly and three gular scales that are twice size of other gular scales; seven supralabials at midorbital positionand 10 to angle of jaw, bordered by a row of flat, somewhat elongated scales slightly larger than their adjacent granules; eight infralabials on left side, ten on right side, infralabials I–V bordered by one or two rows of enlarged scales, anteriormost largest.

Body slender (BW/TRL 0.39), short (TRL/SVL 0.49); dorsal scales heterogeneous, mostly rounded granules intermixed with enlarged tubercles that are irregularly arranged, rounded, feebly keeled to slightly conical, and more or less homogenous in shape and size throughout dorsum; an indistinct ventrolateral fold on either side comprises a single row of small conical tubercles; tubercles extend anteriorly onto eyelids and frontal region; tubercles on nape smaller than those of dorsum; 21 or 22 dorsal tubercles across mid-dorsum; 40 paravertebral tubercles; ventral scales much larger than dorsals, smooth, cycloid, subimbricate; slightly smaller in size under thighs; a row of enlarged subimbricate scales along posterior border of precloacal scales; 42 ventral scales between ventrolateral folds; gular region with much smaller granular scales throughout, except two rows bordering infralabials originating from posterior margin of outer postmentals, which are larger, flat and juxtaposed. A continuous series of eight enlarged precloacal scales, each with a shallow depression, no precloacal or femoral pores, no precloacal groove.

Fore and hind limbs slender; forearm (FL/SVL 0.15) and tibia (CL/SVL 0.18) short; digits short, strongly inflected at each joint, all bearing robust recurved claws that are only slightly longer than their respective claw sheaths; four subdigital lamellae in basal series and eight in distal series with one non-lamellar granule at inflection (digit IV, right manus); six basal and 10 distal lamellae with one non-lamellar granule at inflection (digit IV, right pes); inter-digital webbing absent; relative length of digits: I <II <V <III <IV (left manus) and I <II <V <III <IV (left pes); scales on the palms and soles smooth, flat, juxtaposed; scales on fore limbs heterogeneous, composed of rounded, granular, juxtaposed scales, becoming flat, smooth and subimbricate anteriorly; granules of upper arms and forearms densely interspersed with slightly enlarged rounded tubercles; ventral portion covered mostly with flat, granular, juxtaposed scales; scales on hind limbs heterogeneous, dorsal part of thighs and shanks with small slightly pointed granular scales, intermixed with scattered, enlarged, weakly pointed tubercles; ventral aspect of hind limbs with enlarged, smooth, subimbricate scales.

Tail original with tip removed, somewhat rounded, slender, tapering, divided into indistinct segments; about ten rows of enlarged keeled sub-trihedral tubercles scattered on tail base; 2–5 conical tubercles at end of first to third segments; remaining dorsal caudal scales smooth, rounded, subimbricate, similar in size dorsally and on lateral aspect; subcaudal scales larger than dorsal, smooth, imbricate; no distinct mid-ventral series of enlarged subcaudals; three enlarged smooth post cloacal spurs on each side.

Colouration in life. Not documented for holotype.

Colouration in preservative ( Figs. 16 & 17 ). Dorsal ground colour of head, body, limbs and tail brown; top of head with indistinct darker markings; labials darker than head dorsum with about one light brown blotch per labial; a discontinuous light postorbital streak extends to above ear opening; neck with two longitudinal discontinuous dark streaks; dorsum and dorsolateral aspect with about eight rows of four dark paravertebral blotches; limbs with light grey and tan spots; seven dark and light caudal bands, dark bands twice as wide as light bands; rest of ventral surfaces off-white, immaculate.

Variation ( Fig 9 ). Compared to the holotype, BNHS 2231 has much thicker dark dorsal markings, regenerated tail without spots, an inverted light chevron shaped marking on occiput flanked on either side by a similar coloured spot; postorbital streaks interrupted but meet on base of head; dark and light bands on tail of approximately equal width in some types. The male paratypes have a continuous series of 8–10 precloacal pores ( Table 4), except BNHS 2233 which has four pores on each side separated by a median unpored scale.

Distribution and Natural History. Cyrtodactylus montanus sp. nov. is known only from its type locality, in the Jampui Hills. We collected the type series from rocky roadside cuttings on a mountain-top in approximately one-half of an hour of searching after dark. This high elevation region has a small patch of montane evergreen forest, as opposed to deciduous forest at lower elevations where C. tripuraensis is distributed. A couple of additional populations were observed but not collected in other parts of the Jampui Hills. These populations are provisionally referred to this species due to overall morphological similarity with the type series. One female was found near the peak (~ 23.8098°N, 92.2610°E, ~ 920 m asl.) of Betalongchhip (or Thaidawr: highest peak in Tripura state) approximately 1 km south of Phuldungsei. The individual was located during dusk emerging from a tree hole at approximately 1.5 m above ground level within a forest patch. Two additional populations photographed but not collected were observed ~ 20 km north of the type locality near Vanghmun (~ 24.0055°N, 92.2817°E, ~ 600 m asl.). Eight adult individuals (three males and five females) were observed on an old brick wall after dusk on consecutive nights during the months of June to mid August, after which this population appeared to have dispersed from the wall, as none were observed on the wall during several visits in late August. Nearby the old brick wall was a large dense bamboo brake. Adults spent the day concealed within holes in the wall, emerging only after dusk where they were observed in the open, typically spaced> 1.5 m apart. This population had considerable variation in dorsal markings. Elsewhere near Vanghmun, a male and female were observed on a steep rocky roadside embankment about 1 h after night-fall. Three females observed during late August were gravid with a large pair of eggs (visible through the skin).

Comparisons. Cyrtodactylus montanus sp. nov. is a member of the mountain clade and is sister to C. sp. Mizoram from which it differs by 10.1% uncorrected ND2 p- distance, separated from other members of the clade by p- distance of 19.0–21.5%. Cyrtodactylus montanus sp. nov. can be diagnosed by the presence of 8–10 precloacal pores in a single series (or separated medially by a single scale) in males only from C. gansi (16–29 PcFP) and Cyrtodactylus jaintiaensis sp. nov. (11–12 PcP on both males and females), also distinguished from the latter by its slightly smaller size (SVL up to 78.2 mm vs. up to 96.2 mm); and by the number of dorsal tubercle rows (21–23) from C. brevidactylus (27 DTR) and C. chrysopylos (16 DTR). Cyrtodactylus montanus sp. nov. is distinguished from Cyrtodactylus nagalandensis sp. nov. after its description. 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 15. Cyrtodactylus montanus sp. nov. in life, adult females; top panel paratype BNHS 2231; lower panel uncollected female from the type locality.

FIGURE 16. Dorsal view (A), ventral view (B), and details of dorsal pholidosis (C) of adult female holotype (BNHS 2235) of Cyrtodactylus montanus sp. nov. Scale bars 10 mm.

FIGURE 17. Head of Cyrtodactylus montanus sp. nov. (adult female holotype, BNHS 2235), dorsal (A), lateral (B), and ventral (C) view. Scale bars 10 mm.