Cyrtodactylus namdaphaensis Boruah, Narayanan, Deepak & Das, 2024

Boruah, Bitupan, Narayanan, Surya, Aravind, Neelavar Ananthram, Lalronunga, Samuel, Deepak, V. & Das, Abhijit, 2024, Description of six new species of Cyrtodactylus Gray (Squamata: Gekkonidae) from northeastern India, Vertebrate Zoology 74, pp. 453-486 : 453-486

Cyrtodactylus namdaphaensis Boruah, Narayanan, Deepak & Das sp. nov.

Figure 8 ; Tables 2, S 2

Holotype.

Adult male ( WII-ADR 1416 ), collected from Kamala Valley (27.4595 ° N; 96.4279 ° E; elevation 650 m a. s. l.), Namdapha Tiger Reserve, Changlang District, Arunachal Pradesh, India by Abhijit Das and Bitupan Boruah on 18 May 2022 (Fig. 3 A ).

Paratypes.

Two adult males ( WII-ADR 1415 , WII-ADR 1417 ) collected from the same locality as the holotype on the same date ; one adult female ( WII-ADR 1404 ) collected near Deban (27.4942 ° N; 96.3701 ° E; elevation 400 m a. s. l.), Namdapha Tiger Reserve, Changlang District, Arunachal Pradesh, India by Abhijit Das and Bitupan Boruah on 11 May 2022 ; two adult females ( WII-ADR 3067 , WII-ADR 3068 ) collected from Motijheel trail (27.4899 ° N, 96.3348 ° E; elevation 470 m a. s. l.), Gibbons’ Land, Namdapha Tiger Reserve, Changlang District, Arunachal Pradesh, India by Abhijit Das and Bitupan Boruah on 11 September 2022 ; one adult female ( WII-ADR 1790 ) collected near Burma Nullah (40 mile point) (27.4878 ° N; 96.5416 ° E; elevation 480 m a. s. l.), Namdapha Tiger Reserve, Changlang District, Arunachal Pradesh, India by Abhijit Das and Bitupan Boruah on 18 September 2022 .

Referred materials.

An adult female ( WII-ADR 3060 ) collected from Sinabrai (27.7434 ° N; 96.3872 ° E; elevation 470 m a. s. l.), Kamlang Tiger Reserve, Lohit District, Arunachal Pradesh, India on 5 September 2022 by Bitupan Boruah and Abhijit Das ; an adult female ( WII-ADR 3281 ) and an adult male ( WII-ADR 3282 ) collected from Hornbill (27.5381 ° N; 96.4403 ° E; elevation 670 m a. s. l.), Namdapha Tiger Reserve, Changlang District, Arunachal Pradesh, India on 10 May 2023 by Rajiv N. V.

Diagnosis.

Medium-sized gecko (SVL 57.5–70.7 mm in males and SVL 54.8–69.3 mm in females); supralabials and infralabials 8–11; dorsum with weakly keeled and bluntly conical tubercles, 29–36 paravertebral tubercles between the level of axilla and level of groin; 17–19 dorsal tubercle rows at mid body; 33–40 mid ventral scale rows; seven to nine precloacal pores in males and 8–10 small precloacal pores in females in a continuous series, PcP much smaller in females than that of males; 12–14 subdigital lamellae on finger IV and 11–17 subdigital lamellae on toe IV; irregular dark-brown spots or stripes on dorsum.

Description of holotype.

Holotype well preserved except a ventrolateral incision below left axilla. Snout-vent length 65.3 mm. Head moderately large (HL / SVL = 0.27), dorsoventrally depressed, ovoid in shape, longer than width (HW / HL = 0.66), distinct from neck, broader at occipital region; snout rounded in both dorsal and lateral view; loreal region convex; canthus rostralis rounded, indistinct; interorbital space flat, a longitudinal furrow on dorsal surface of the snout, snout short (SO / HL = 0.4), longer than orbit (OD / SO = 0.71); nostril semicircular, opening directed posterolaterally; ear opening oval and oblique; scales on head heterogeneous, largest on snout and loreal region, posteriorly smaller, interorbital space and occipital region, granular juxtaposed; scales on upper eyelids nearly homogeneous, granular juxtaposed; supraciliaries outwardly sharp giving serrated appearance in dorsal view, size anteriorly and posteriorly decreases, largest at the anterodorsal region; rostral wide, a short groove at the middle on top, rostral connected with nasals, supranasals, internasals and first supralabials; granular scales at parietal, occipital and temporal region intermixed with slightly large, rounded and bluntly conical tubercles, dense in occipital and temporal region and size increases towards nape; supralabial 11 on right and 10 on left side, supralabials up to midorbit eight on right and seven on left side, size decreases towards angle of jaw; a series of scales slightly larger than the loreal scales present above the supralabials, posteriorly size decreased; mental as wide as rostral, nearly triangular, connected with first infralabials, inner postmentals; nine infralabials on right and eight on left side, size decreases towards angle of jaw; inner pair of postmentals are larger than the outer postmentals; two rows of enlarged scales along the infralabials starting below the outer postmentals, posteriorly size of those decreases; rest of the gular scales are small, granular juxtaposed, homogeneous, size increases towards throat where they becomes imbricate.

Habitus slender (BW / SVL = 0.17, TRL / SVL = 0.47), dorsoventrally depressed; dorsal scales granular, rounded, heterogeneous, intermixed with rounded, irregularly arranged weakly keeled and bluntly conical tubercles, these tubercles continues to fourth segment of the tail, size increases towards posterior body and pronounced; 18 dorsal tubercles across mid dorsum; 36 paravertebral tubercles; ventrolateral fold weak; ventral scales larger than those of dorsal, flat, smooth, cycloid subimbricate to imbricate, largest towards belly; 40 mid-ventral scales between ventrolateral fold; seven precloacal pores arranged in an inverted “ V ” shaped continuous series, followed by five unpored, large scales below it, one enlarged unpored scale present on right end of the PcP series.

Forelimbs and hindlimbs slender (FL / SVL = 0.15, CL / SVL = 0.18); digits strongly inflected at the joints, all bearing large recurved claw, enlarged subdigital lamellae; lamellae beneath digit IV of right and left manus (given as basal + distal) is 5 + 8; lamellae beneath digit IV of right and left pes (given as basal + distal) is 6 + 8 and 5 + 8 respectively; dorsal scales on forelimbs smooth, subimbricate and heterogeneous, small and granular at elbow, scales on forearm nearly rounded while those on hind arm are posteriorly tapering; forearm scales intermixed with enlarged rounded and bluntly conical tubercles; dorsal scales of hindlimbs heterogeneous, intermixed with large, rounded and bluntly conical tubercles, dense than those on forelimbs; horizontally upper half of the thigh scales are smooth, large and subimbricate, those on lower half small granular; scales on tibia are small, granular juxtaposed; ventral scales of forelimbs granular, juxtaposed, mostly homogeneous; scales on palm heterogeneous in shape and size, granular juxtaposed; scales on ventral side of hindlimbs smaller than those of belly, smooth, cycloid and subimbricate, but on the knee, above cloaca and on thigh below the level of precloacal pores are smaller and granular; scales on soles heterogeneous, granular, juxtaposed to subimbricate.

Tail regenerated (TL = 79 mm), slender, gradually tapering towards tip, segments indistinct, in the original part of the tail dorsal scales small, granular, juxtaposed at the base, posteriorly size increases, flat, smooth, subimbricate, heterogeneous in shape and size; in the regenerated part of the tail, scales are irregular in shape and size; large feebly keeled scales upto fourth segment of the tail, those on basal segment are pronounced; subcaudal scales smooth, subimbricate, wider than that of dorsal, heterogeneous in shape and size; no enlarged plate like series of subcaudal scales; two and four bluntly conical spurs on right and left side of the tail base respectively.

Colouration in preservative.

Top of head pale-brown, upper eyelids grey; neck and dorsum dorsally greyish-brown; two brown stripes with irregular edge on dorsal side of the neck continuing to the level of forelimb insertion, and another stripe on each lateral side of the neck; seven pairs of slightly dark-brown elongated spots of irregular shape and size on dorsum, these spots are outwardly connected to a narrow, brown dorsolateral stripe; tail dorsally pale-brown with broad dark-brown cross bars of irregular shape and size on the original part, the first bar broken into two elongated spots, regenerated part of the tail is plain pale-brown; ventrally head, trunk and tail pale-cream coloured, a few irregular brown spots on tail.

Colouration in life.

(Based on paratype WII-ADR 1417 ) (Fig. 8 I ); head dorsally brown with irregular dark-brown patches, a pair of pale-yellowish spots on loreal in front of anterodorsal corner of eyes, lips slightly paler than dorsal head colour with irregular pale-yellowish spots; a pale-brown postorbital streak; pale-brown irregular spots on dark-brown background on neck; upper eyelids greyish-brown; slightly dark-brown large spots of irregular size and shape on dorsal and lateral side of the trunk, interspaced with pale-brown patches, dark-brown spots on dorsal side of the trunk giving appearance of continuous stripes up to middle of the trunk; anterior two third of dorsal side of the tail with alternative broad dark-brown and narrow pale-brown bands, those dark-brown bands anteriorly diffused and posterior edge zigzagged, posterior one third brown with dark-brown marbling; limbs brown with irregular pale spots and dark-brown reticulation; digits with alternative dark-brown and pale-brown bands.

Morphological variation.

Morphological variations are given in Table S 2. Except for those, the dorsal marking pattern varied among the collected specimens. The dorsal spots of WII-ADR 1417 are in the form of two continuous stripes starting from neck, posteriorly broken; a spot at the middle of occipital region followed by a dark cross bar on the nape; WII-ADR 3067 and WII-ADR 3281 has four dorsal stripes starting from neck to the level of hind limb insertion; WII-ADR 3068 has four stripes on neck, followed by five irregular and zigzag cross bars on dorsum; in WII-ADR 1790 , dorsal spots are indistinct and irregular; WII-ADR 1415 has three pairs of dark spots posteriorly bordered with white spots on neck, cross bars on dorsum narrower, irregular and posteriorly with white (Fig. S 2); WII-ADR 3060 has six dark brown cross bands on back between the level of axilla and groin, consists of irregular shaped enlarged individual spots, mid dorsally these spots are remarkably disjunct,. Precloacal pores in females are smaller than that of males.

Comparison.

Cyrtodactylus namdaphaensis sp. nov. differs from C. mombergi by fewer dorsal tubercle rows, DTR 17–19 (vs. DTR 23–27), by fewer precloacal pores, PcP 7–9 (vs. PcP 10–11). Morphological differences with other members of khasiensis group is presented in Table 2 .

Sequence divergence.

Cyrtodactylus namdaphaensis sp. nov. has a moderate genetic divergence of 6.2–7.9 % from the closely related C. mombergi . The intraspecific divergence among the thirteen samples of C. namdaphaensis sp. nov. ranges between 0.1–5 %.

Etymology.

The specific epithet is a toponym named after its type locality Namdapha Tiger Reserve in Arunachal Pradesh, India.

Suggested common name.

Namdapha bent-toed gecko.

Distribution and natural history.

So far, Cyrtodactylus namdaphaensis sp. nov. has been recorded within an elevational range of 400–650 m a. s. l. inside Namdapha Tiger Reserve. All the localities are south of Noa-Dihing River in Changlang District, Arunachal Pradesh, India. We recorded this species between May and September 2022. Individuals were recorded on tree bark, ferns, and riparian vegetation and along forest trails between 18: 00–23: 00 hrs. The forest type can be classified as Assam Valley Tropical Evergreen Forest. The area had a distinct understory with a thick covering of leaf-litter. Currently the species has been recorded from 25 Mile, Burma Nullah (40 Mile), Gibbons Land, Motijheel trail and at Hornbill camp located at the north bank of Noa-Dihing River within the Namdapha Tiger Reserve. We also recorded this species on rocks and vegetation near Kamlang River at Sinabrai, near the Kamlang Tiger Reserve, at an elevation of 470 m a. s. l. We observed juveniles of this species on the forest floor in the leaf litter during May, 2022. During 2023, adult individuals were seen on the ferns overhanging first order streams. At the slightest disturbance, the lizards would drop into the thick vegetation below. Other arboreal reptile taxa from the area included Ptyctolaemus sp. , Japalura sp. and Pareas sp.

Figures

Figure 3. Map showing geographic distribution of the clades within the khasiensis group. A type localities of the members of the four clades in the Indo-Burma region: 1 Cyrtodactylus septentrionalis, 2 C. guwahatiensis, 3 C. urbanus, 4 C. kazirangaensis, 5 C. siangensis sp. nov., 6 C. cayuensis, 7 C. namdaphaensis sp. nov., 8 C. bapme, 9 C. karsticola, 10 C. agarwali, 11 C. exercitus, 12 C. jaintiaensis, 13 C. khasiensis, 14 C. barailensis sp. nov., 15 C. nagalandensis, 16 C. kiphire sp. nov., 17 C. namtiram, 18 C. vairengtensis, 19 C. manipurensis sp. nov., 20 C. mombergi, 21 C. dianxiensis, 22 C. tripuraensis, 23 C. montanus, 24 C. aaronbaueri, 25 C. bengkhuaiai, 26 C. ngopensis, 27 C. lungleiensis, 28 C. ngengpuiensis sp. nov., 29 C. siahaensis, 30 C. gansi, 31 C. myaleiktaung, 32 C. brevidactylus, 33 C. aunglini, 34 C. chrysopylos, 35 C. ayeyarwadyensis; B cayuensis clade, green star (type locality of C. siangensis sp. nov.), pink star (type locality of C. cayuensis), pink triangle (C. “ arunachalensis ”), pink circle (C. cayuensis recorded in this study) (numbers correspond to the locality given in Table 1).

Figure 8. Cyrtodactylus namdaphaensis sp. nov. A – G holotype (WII-ADR 1416), A dorsal, and B ventral view of the whole body; C dorsal, D ventral, and E lateral view of head; F ventral view of left manus and G left pes; H precloacal pores of paratype WII-ADR 1417; I paratype WII-ADR 1417, and J paratype WII-ADR 1415 in life. Scale bar: 10 mm. I, J not to scale.