Cyrtodactylus arunachalensis, Mirza & Bhosale & Ansari & Phansalkar & Sawant & Gowande & Patel, 2021

Mirza, Zeeshan A., Bhosale, Harshal, Ansari, Faizan, Phansalkar, Pushkar, Sawant, Mandar, Gowande, Gaurang & Patel, Harshil, 2021, A new species of geckos of the genus Cyrtodactylus Gray, 1827 from Arunachal Pradesh, India, Evolutionary Systematics 5 (1), pp. 13-23 : 13

Cyrtodactylus arunachalensis sp. nov. Figs 1 , 2 , 3 , 4 , Tables 1, 2

Cyrtodactylus sp. Agarwal et al. (2014): 147

Type material.

Holotype. male, BNHS 2775, Seijosa near Pakke Tiger Reserve, East Kameng District, Arunachal Pradesh (26.966819°N, 93.01332°E, elevation 179 m) collected by Mandar Sawant, Pushkar Phansalkar, Harshal Bhosale and Zeeshan A. Mirza on 1 July 2019.

Paratypes. three males BNHS 2776 & NCBS NRC-AA-0006-NRC-AA-0007, one female BNHS 2777, from the same locality collected on 3 July 2019.

Material referred.

three males, NCBS NRC-AA-0008-NRC-AA-0009 & BNHS 2778, from near Parshuram Kund near Kamlang Wildlife Sanctuary (27.887369°N, 96.376617°E, elevation 560 m) and Hawa Pass (27.916699°N, 96.332303°E, elevation 1217 m) collected by Mandar Sawant, Pushkar Phansalkar, Harshal Bhosale, Gaurang Gowande and Zeeshan A. Mirza; one female, BNHS 2779 from near Dakte - Hoj, Papum Pare District, Arunachal Pradesh (27.332567°N, 93.83775°E, elevation 980 m) collected by Mandar Sawant, Pushkar Phansalkar and Harshal Bhosale.

Etymology.

The specific epithet is refers to the state of Arunachal Pradesh in northeast India where the species was discovered.

Diagnosis.

Cyrtodactylus arunachalensis sp. nov. can be distinguished from members of the Cyrtodactylus khasiensis group by its: moderate body size (SVL 64.9-81.7, mean 70.6); 8-11 supralabials; 8-10 infralabials; 24-26 rows of bluntly conical, feebly keeled dorsal tubercles; 50-60 paravertebral tubercles; ~38 ventral scales between ventrolateral folds; no precloacal groves; 6-10 precloacofemoral pores in a continuous series; three to four rows of enlarged scales below pored scales, slightly larger than pored scales; 10-16 distal subdigital lamellae on IV of pes; subcaudal scalation of original tail without enlarged plates.

Comparison.

Molecular data for ND2 gene suggests that Cyrtodactylus arunachalensis sp. nov. is a member of the clade of species distributed south of Brahmaputra River ( Agarwal et al. 2014) and is here compared with members of the clade. Intraspecific uncorrected pairwise sequence divergence (p -distance) for samples across the state in 0-5% and an interspecific divergence of 19-30% calculated for ND2 gene. Precloacal pores 6-10, and no femoral pores (vs. 10-28 in C. ayeyarwadyensis Bauer, 16-29 in C. gansi Bauer, 29-37 in C. tripuraensis Agarwal, Mahony, Giri, Chaitanya and Bauer, 14 in C. septentrionalis Agarwal, Mahony, Giri, Chaitanya and Bauer, 11-12 in C. jaintiaensis Agarwal, Mahony, Giri, Chaitanya and Bauer, 26-39 precloacofemoral pores in C. guwahatiensis Agarwal, Mahony, Giri, Chaitanya and Bauer); 24-26 dorsal tubercle rows (vs. 19-23 in C. khasiensis (Jerdon), 19-21 in C. tripuraensis Agarwal, Mahony, Giri, Chaitanya and Bauer, 16 in C. chrysopylos Bauer, 19-20 in C. jaintiaensis , 21-23 in C. montanus Agarwal, Mahony, Giri, Chaitanya and Bauer, 16-18 in C. nagalandensis Agarwal, Mahony, Giri, Chaitanya and Bauer); supralabials 8-11 (vs. 11-12 in C. kazirangaensis Agarwal, Mahony, Giri, Chaitanya and Bauer); 37-38 mid-ventral scale rows across belly (vs. 32-37 in C. ayeyarwadyensis , 30-34 in C. urbanus Purkayastha, Das, Bohra, Bauer & Agarwal, 41-49 in C. aunglini Grismer, Wood, Thura, Win, Grismer, Trueblood & Quah, 57 in C. myaleiktaung Wood, Thura, Win, Grismer, Trueblood & Quah); 50-57 paravertrbral tubercles (30-35 in C. guwahatiensis , 37-43 in C. kazirangaensis , 34-42 in C. khasiensis , 38-42 in C. septentrionalis , 37-40 in C. urbanus ).

Description of holotype male BNHS 2775.

Holotype in generally good condition except for minor folds of skin on flank and ventral scales, all artefacts of preservation; tail tip removed as tissue sample for molecular analyses; part of the scales on the left lower side of the trunk was damaged during capture (Fig. 4A ).

Adult male, SVL 71.6 mm. Head moderately long (HL/SVL ratio 0.25), and wide (HW/HL ratio 0.76), dorsoventrally depressed (HH/HW ratio 0.53), distinct from neck; loreal region slightly inflated, interorbital area flat, canthus rostralis not prominent; snout moderately short (SE/HL ratio 0.44), almost twice as long as OD (OD/SE ratio 0.75); scales on forehead, canthus rostralis and snout heterogenous, those in the interorbital region small, rounded and granular; scales on snout and canthus rostralis slightly larger than those on forehead; scales of interorbital and occipital region homogenous, granular, those in occipital region mixed with slightly larger, rounded, conical tubercles (Fig. 5A ). Eye large (OD/ HL ratio 0.33); pupil vertical with crenulated margins; supraciliaries mucronate, decreasing in size towards posterior edge of orbit; ear opening oval, obliquely oriented, large; eye to ear distance slightly more than eye diameter. Rostral wider (2.5 mm) than deep (1.7 mm), partially divided dorsally by weakly developed rostral groove; single large supranasal on either side, separated by two small scales (internasals), which are approximately twice the size of enlarged granular scales on snout; rostral in contact with SL I, nasals, supranasals and an internasal; nostrils semicircular, laterally oriented, posterior half covered by nasal pad, each in broad contact with rostral and also surrounded by supranasal, SL I, and three or four postnasals; three or four scale rows separate orbits from supralabials; mental slightly wider (2.5 mm) than long (1.8 mm), triangular, two pairs of well-developed postmentals, inner pair longer (maximum length 1.7 mm) than and separating outer pair (maximum length 1.0 mm), outer pair in contact with the inner postmentals for its entire length; inner postmentals bordered by mental, IL I, outer postmental and six gular scales; outer postmental bordered by inner postmental, IL I and IL II, and four gular scales on either side; supralabials 10/11 (8), bordered by a row of large, flat, slightly elongated scales (Fig. 5C ); infralabials 8/9, IL II to IL VII bordered by one row of chin shields, largest anteriorly; interorbital scale rows across narrowest point of frontal bone approximately 30. Body moderately slender, relatively short (TrL/SVL ratio 0.46) with weak ventrolateral folds; dorsal scales heterogeneous, mostly rounded granular, intermixed with irregularly arranged small (2-3 times granule size) circular tubercles, bluntly conical and feebly keeled throughout (Fig. 4 ), becoming more conical and smaller towards flanks, tubercles extend from frontal region to proximal one third of tail length; tubercles on nape smaller than those of dorsum, largest on flanks; enlarged tubercles on tail completely flat and weakly pointed and keeled; tubercles in approximately 24 irregular longitudinal rows at mid-body; 57-60 paravertebral tubercles; ventral scales much larger than dorsal scales, smooth, cycloid, imbricate to subimbricate, 37-38 mid-body ventral scale rows; gular scales smaller than ventrals and granular except a few rows of larger, flat and juxtaposed scales, including a single row of chinshields bordering mental, postmentals and infralabials (Fig. 5C ). Six pored precloacal scales in a continuous series; no precloacal groove. Three to four rows of enlarged post-precloacal scales between pitted precloacal scales and vent, as large as the largest ventrals and first as well as second row of scales much larger than pitted precloacal scales, the other two rows are slightly smaller. Tail partly regenerated, dorsoventrally depressed, without distinct median furrow, tapering; tail tip removed for molecular analyses. Dorsal scales at base of tail granular, gradually becoming flatter, subimbricate posteriorly, increasing in size on lateral aspect, intermixed with 11-12 slightly enlarged tubercles near base of tail and reducing to two by fourth transverse row of tubercles (Fig. 4 ); ventral scales larger that dorsal scales, imbricate, median row comprises irregularly enlarged subcaudals in one or two rows; two enlarged postcloacal tubercles at base of tail. Fore and hindlimbs relatively slender; forearm (FL/SVL ratio 0.14) and crus (CL/SVL ratio 0.16) relatively short; digits relatively short, strongly inflected at each joint, all bearing robust, recurved claws; subdigital lamellae widened beneath basal phalanx; basal lamellae series on Digits I-V: 5-5-5-5-4 (right manus) and 5-6-5-5-5 (right pes); apical lamellae series on Digits I-V: 11-12-13-10-9 (right manus) and 10-11-14-14-10 (right pes); interdigital webbing absent on manus, rudimentary between Digits I-V of pes; relative length of digits (measurements in mm in parentheses): V (4.4) < I (4.9) < IV (5.1) < III (6.3) < II (6.4) (right manus) and I (5.7) < II (6.1) < V (7.3) < III (7.5) < IV (8.4) (right pes); palmar and plantar scales smooth, rounded; scales on forelimb heterogeneous, composed of flat, rounded, smooth sub-imbricate scales, gradually increasing in size on forearm, smaller scales appear granular, no enlarged tubercles, ventral portion covered mostly with smaller and granular scales; scales on hindlimbs heterogeneous, dorsal part of thigh and shank, with larger, conical granular scales, intermixed with scattered, enlarged, slightly conical, weekly keeled tubercles, which are denser on shank than on thigh, anterior portion of thigh and ventral aspect of hindlimb with enlarged, smooth, imbricate scales, a few rows under thigh are slightly larger than those on abdomen (Fig. 4 ).

Colouration in preservative: Background in a shade of beige with four rows of dark irregular blotches running from the nape to the flank; each of these blotches are placed fairly at an equal distance from each other. These blotches merge into alternating dark and light bands on the tail. The limbs bear dark unconnected reticulations. The ventral aspect is off white lacking any mottling.

Variation.

The paratypes and non-type specimens match the holotype in most aspects except for details presented here and in Table 1 : the number of post cloacal spurs in variable in the species ranging from 2 in most specimens to 2/3 ( BNHS 2778), 3/4 ( BNHS 2776, NCBS NRC-AA-0006), 3/3 ( BNHS 2777); tubercle rows on the first tail segment in the types series ranges from 11-13 however, NCBS NRC-AA-0008-NRC-AA-0009 & BNHS 2778 bear 15-16 tubercles rows. BNHS 2777 has 8 pre-cloacal pores, NCBS NRC-AA-0006 has 7, whereas NCBS NRC-AA-0007 has 10 pores. The coloration in the species is quite variable (Fig. 4 ).

Natural history notes.

All the specimens of the new species were collected form near culverts along roads just after dusk. Other than the concrete culverts, individuals were also observed on tree trunks, low branches, broad-leafed shrubs and rocky cliffs. The species was found in sympatry with Hemidactylus cf. malcolmsmithi , H. cf. frenatus and H. platyurus . The species appears to be distributed across the state and confirmed localities where it exists are Pakke Tiger Reserve, Papum Pare district and Kamlang Wildlife Sanctuary with recorded elevation ranging from 170 to 1400 m (Fig. 5 ).

Figures

Figure 1. Cyrtodactylus arunachalensis sp. nov. male holotype BNHS 2775, (a) dorsal view, (b) ventral view. Scale bars: 10 mm.

Figure 2. Cyrtodactylus arunachalensis sp. nov. male holotype BNHS 2775 head, (a) dorsal view, (b) ventral view, (c) lateral view. Scale bars: 5 mm.

Figure 3. Cyrtodactylus arunachalensis sp. nov. male holotype BNHS 2775 dorsal trunk showing arrangement of tubercles.

Figure 4. Cyrtodactylus arunachalensis sp. nov. in life (a) male holotype BNHS 2775, (b) paratype male BNHS 2777, (c) male NCBS NRC-AA- 0008, (d) male BNHS 2778. Photographs by Zeeshan A. Mirza

Figure 5. Map of northeast India showing the distribution of the new species, type locality denoted by the black star and other localities by solid black circles. Inset map shows location of Arunachal Pradesh in India.