Cyrtodactylus urbanus, Purkayastha & Das & Bohra & Bauer & Agarwal, 2020

Purkayastha, Jayaditya, Das, Madhurima, Bohra, Sanath Chandra, Bauer, Aaron M. & Agarwal, Ishan, 2020, Another new Cyrtodactylus (Squamata: Gekkonidae) from Guwahati, Assam, India, Zootaxa 4732 (3), pp. 375-392 : 384-387

Cyrtodactylus urbanus sp. nov.

Figs. 5–9 , Table 4

Holotype. VR/ ERS /ZSI/683, adult male, SVL 71.9 mm. Basistha , Guwahati, Assam State, India (26.106301°N, 91.787199° E), 106 m elevation above sea level, collected on 13 June 2018, by Jayaditya Purkayastha.

Paratypes. Adult females (VR/ ERS /ZSI/684, SVL 74.3 mm; VR/ ERS /ZSI/688, SVL 75.6 mm and VR/ ERS / ZSI/689, SVL 73.2 mm), Adult males (VR/ ERS /ZSI/685, SVL 65.4 mm; VR/ ERS /ZSI/686, SVL 68.6 mm; VR/ ERS /ZSI/687, SVL 70.3 mm); same collection details as holotype .

Diagnosis and comparison with regional congeners. Cyrtodactylus urbanus sp. nov. can be distinguished from regional congeners by its moderate body size (SVL to 74.0 mm); 9–11 supralabials; 8–10 infralabials; 21–24 longitudinal rows of bluntly conical, feebly keeled dorsal tubercles; tubercles extending beyond base of tail; 38–45 paravertebral tubercles; 30–34 mid-ventral scales; no precloacal groove; 9–12 precloacal pores in a contiguous series, no femoral pores or pits; a row of enlarged scales above and below precloacal pore-bearing scales, slightly larger than pore-bearing scales;. There are 5–6 basal lamellae, 1–4 broken lamellae and 8–10 distal lamellae under 4 th finger and 6–7 basal lamellae, 2–3 broken lamellae and 10–12 distal lamellae under 4 th toe. Subcaudal scalation of original tail without enlarged plates. Dorsal pattern of 6–7 longitudinal rows of two indistinct transverse pale buff blotches outlined by light edges, light mid-dorsal line. Tail with alternating dark and lighter bands. Iris in life silver-grey with brown reticulations.

Cyrtodactylus urbanus sp. nov. can be differentiated from other members of the C. khasiensis group by the following characters (see Table 5 ): 9–12 precloacal pores in males (versus 10–28 precloacofemoral pores in C. ayeyarwadyensis ; 26–39 precloacofemoral pores which may be interrupted by up to 11 unpored scales in C. guwahatiensis ; 29–37 precloacofemoral pores in C. tripuraensis ) and 30–34 MVSR (versus 37–43 in C. kazirangaensis ). The new species may be distinguished from C. septentrionalis by a slightly lower precloacal pore count in males (9–12 versus 13–14), more subdigital lamellae beneath toe IV of the pes (19–21 versus 15–20) and fewer scales across the belly (30–34 versus 35–38). Furthermore, Cyrtodactylus urbanus sp. nov. differs from C. ayeyarwadyensis in having a prominent mid-dorsal stripe (absent in C. ayeyarwadyensis ) and fewer transverse blotches on the dorsum (6–8 versus 9–11) Cyrtodactylus urbanus sp. nov. is very similar to C. khasiensis , from which it differs in mean counts across a number of characters as follows: Cyrtodactylus urbanus sp. nov. has fewer paravertebral tubercles (38–40 versus 42–53 in C. khasiensis ); fewer mid-ventral scale rows (30–34 versus 34–42); and fewer apical subdigital lamellae (8–10 versus 13–15). The tail pattern in the original tail of the new species has approximately 14 dark bands, the first six similar to spots on the dorsum, whereas the original tail of C. khasiensis has approximately 11 dark bands, the first two similar to spots on the dorsum.

Etymology. The specific epithet is an adjective meaning of or belonging to a city and reflects the urban habitat of the species, through which we also wish to highlight the importance of urban biodiversity. We propose Urban bent-toed gecko as common name for the gecko.

Description of holotype. Adult male, SVL 71.9 mm, with both hemipenes everted. Head just more than onefifth of SVL (HL/SVL 0.23), wider than long (HW/HL 0.68), somewhat depressed (HD/HL 0.52), distinct from neck; loreal region somewhat inflated, interorbital area flat, canthus rostralis not prominent; snout slightly less than half of the head length (SE/HL 0.46), twice as long as orbit diameter (OD/SE 0.53); scales on forehead, canthus rostralis and snout homogeneous. Scales from posterior margin of eyes to nape smaller than those of forehead, roughly hexagonal, juxtaposed and weakly pointed; scales on interorbital and occipital regions heterogeneous, without distinct tubercles. Eye one quarter of head length (OD/HL 0.25); pupil vertical with crenulate margins; supraciliaries small, spiny, decreasing in size towards posterior end of orbit, those on the anterior end of orbit largest; ear opening oval, obliquely oriented, one-tenth of the head length (EL/HL 0.10); eye to ear distance about half eye diameter (OD/SE 0.54). Rostral wider than deep (RL/RW 0.60), partially divided dorsally by weakly developed rostral groove; single much enlarged supranasal on either side, separated by two small internasal, about the same size as enlarged scales on snout; rostral in contact with first supralabials, nasals, supranasals and an internasal; nostrils semicircular, laterally oriented, posterior half covered by nasal pad, each in broad contact with rostral and surrounded by supranasal, first supralabial, and three postnasals; two rows of scales separate orbit from supralabials; mental wider (2.1 mm) than long (1.5 mm), triangular; two well developed postmentals on either side, inner pair more than twice the size (2.6 mm) of and separating outer pair (1.0 mm), in moderate contact (1.2 mm) behind mental; inner postmentals bordered by mental, infralabial I, outer postmental and six gular scales; outer postmental bordered by inner postmental, infralabial I and II, and four gular scales on either side; supralabials (to midorbital position) 10 (right) – 9 (left), bordered by a row of large, flat, somewhat elongate scales; infralabials 9, infralabials I to III bordered ventrally by a row of enlarged scales, largest anteriorly.

Body moderately slender, trunk slightly less than half of SVL (TRL/SVL 0.43) with weakly developed ventrolateral folds that are not denticulate; dorsal scales heterogeneous, mostly rounded granules, intermixed with irregularly arranged, enlarged tubercles (2–4 times size of granules), bluntly conical and feebly keeled throughout, becoming more conical and slightly smaller towards flank, largest on the sacral region, ventrolateral folds with single row of scattered enlarged, smooth tubercles; tubercles extend from occipital region beyond the tail base; tubercles on nape smaller than those of dorsum; tail flat, weakly pointed and feebly keeled; 22 rows of dorsal tubercles; 45 paravertebral tubercles; ventral scales much larger than dorsals, smooth, cycloid, imbricate to subimbricate; slightly smaller in size under thighs, no enlarged scales between precloacal pores and vent; scales across the belly 31; gular region with small granular scales throughout except a few rows bordering mental, postmentals and infralabials larger, flat and juxtaposed. Nine distinct precloacal pores in a continuous series, precloacal grooves absent, hemipenal bulge distinct.

Forearm (FL/SVL 0.15) and tibia (CL/SVL 0.17) short; digits relatively short, strongly inflected at each joint, all bearing robust, recurved claws; subdigital lamellae widened beneath basal phalanx; basal lamellae 4–5–6–6–4 (right manus) and 4–5–5–7–5 (right pes); distal lamellae (intervening rows of nonlamellar granules between basal and distal lamellae series in parentheses): 6(1)–8(2)–10(3)–9(4)–9(2) (right manus) and 7(2)–9(2)–10(2)–11(2)– 10(2) (right pes); interdigital webbing absent from both manus and pes; relative length of digits: I <V <II <III <IV (right manus) and I <II <V <III <VI (right pes); scales on the palm and sole smooth, weakly raised, subimbricate; scales on forelimb heterogeneous, comprising flat, subimbricate scales on upper arm, those on forearm heterogeneous, ventral portion covered heterogenous imbricate scales; scales on hindlimbs heterogeneous, dorsal part of thigh and shank with larger scales, intermixed with scattered, enlarged, conical, feebly keeled tubercles; anterior portion of thighs and ventral aspect of hindlimbs with much enlarged, smooth, imbricate scales. Tail original, complete, rounded in cross-section, slender, tapering; Two rows of enlarged, flat, weakly pointed, smooth, tubercles positioned paravertebrally on tail base only, remaining dorsal caudal scales smooth, rounded, subimbricate, similar in size dorsally but becoming larger on lateral aspect; subcaudal scales larger, smooth, imbricate with midventral series of paired scales; no enlarged plates.

Colouration in life ( Fig. 5 ). Dorsal ground colouration dark brown. Head has dark brown ground colour with faint yellow patches behind the nasal scales as well as in the supraciliary region. Nape has few cream coloured spots on brown ground colour. The dorsal part of trunk region shows alternating dark and light pattern, a mid-dorsal cream coloured line divides the trunk and extends posteriorly to the level of the cloaca. The dorsal markings are “w” shaped. The same markings continue onto the tail extending to the tail tip, reducing, however, to simple transverse bars on the distal portion of the tail. The caudal region has 14 dark bands alternating with lighter ones. The thigh and hind limbs show indistinct cream coloured blotches or crossbars alternating with dark brown ground colour. Similar pattern observed in the forelimb.

Hemipenis. The hemipenis of the holotype of C. urbanus sp. nov. is bilobed, elongated and muscular, but the lobes are not clearly distinguishable or demarcated. The apex seems bulbous and almost round in shape with no ornamentation on the sulcal surface. The length of the lobe of the hemipenis is almost 1/4 th of its total length (hemepenis length= 5.2 mm, lobe length= 2.1 mm). The sulcus spermaticus is clearly bifurcated, goes around the lobe head before entering it. The sulcus spermaticus is deeply grooved. The asulcal surface has mildly rough, granules present on the lobe head. The pedicel is unadorned on both sulcal and asulcal surfaces.

Distribution and Natural History. This species is only known from degraded moist deciduous forests in and around Guwahati, Assam; based on voucher specimens from the type locality, Basistha, and photographic vouchers from Deeporbeel, Garbhanga Reserve Forest, Gotanagar and Rani Reserve Forest. The type series was collected from around the Basistha Temple in Guwahati ( Fig. 9 ) on 13 June 2018 between 1900h and 2100h. The animals were seen to be active between the months of March and November. Being a nocturnal species, they are most active two to five hours after dark and are mostly seen inside rock crevices and small rocky caves which are associated with running hill streams. Gravid females were observed from mid-April to early August. The diet of this species primarily consists of spiders, crickets and other small arthropods. In one instance we also found semi-digested ecdysed skin of Cyrtodactylus in the stomach.

Figures

FIGURE 5. A: Dorsal view, B: ventral view and C: details of dorsal pholidosis of Cyrtodactylus urbanus sp. nov. (male holotype, VR/ERS/ZSI/683) in life.

FIGURE 6. Head of Cyrtodactylus urbanus sp. nov. (male holotype, VR/ERS/ZSI/683), A: dorsal view B: lateral view and C: ventral view.

FIGURE 7. Fully everted hemipenis of Cyrtodactylus urbanus sp. nov. (male holotype, VR/ERS/ZSI/683), A: sulcal view and B: asulcal view.

FIGURE 8. Type series of Cyrtodactylus urbanus sp. nov. Individuals are labeled by VR/ERS/ZSI specimen number.

FIGURE 9. Habitat of Cyrtodactylus urbanus sp. nov., Basistha, Guwahati, Assam