Cyrtodactylus agarwali, Purkayastha & Lalremsanga & Bohra & Biakzuala & Decemson & Muansanga & Vabeiryureilai & Chauhan & Rathee, 2021

Purkayastha, Jayaditya, Lalremsanga, Hmar Tlawmte, Bohra, Sanath Chandra, Biakzuala, Lal, Decemson, H. T., Muansanga, Lal, Vabeiryureilai, Mathipi, Chauhan, Suraj & Rathee, Yashpal Singh, 2021, Four new Bent-toed geckos (Cyrtodactylus Gray: Squamata: Gekkonidae) from northeast India, Zootaxa 4980 (1), pp. 451-489 : 462-466

Cyrtodactylus agarwali sp. nov.

Figs. 5 , 6 , 11b ; Appendix IV; Table 2

Holotype. Adult male ( MZMU2160 ; Fig. 5 ), from nearby National Highway 217 (25.358962°N, 90.664637°E; elevation 270 m asl.), outskirts of Siju village, South Garo Hills District, Meghalaya state, northeast India, collected on 22 November 2020 by Yashpal Singh Rathee, Jayaditya Purkayastha, Sanath C. Bohra and Suraj Chauhan.

Paratypes. Three adult males ( MZMU2157 ; MZMU2159 ; MZMU2161 ), one sub-adult male ( MZMU2158 ), same collection details as holotype (Appendix IV) .

Definition. Cyrtodactylus agarwali sp. nov. is a moderate-sized gecko (adult SVL 56.4–71.8 mm); 9–12 supralabials; 8–10 infralabials; dorsal tubercles are rounded, conical to weakly keeled and are in 21–25 longitudinal rows; 34–38 paravertebral tubercles; 32–39 mid-ventral scale rows; 11–18 precloacal pores in males; 15–19 subdigital lamellae under toe IV; no single row of transversely enlarged subcaudal scales; 8–9 pairs of dark brown blotches on the dorsum of the body; original tail with 14 alternating dark and light bands.

Description of holotype ( Fig. 5 ). Holotype in generally good preservation condition, tail autotomised from the third post-pygal segment and not preserved with the specimen.

Adult male, SVL 69.3 mm. Head more than one-quarter of SVL (HL/SVL 0.27), longer than broad (HW/HL 0.63), depressed (HD/HW 0.64), distinct from neck; loreal region inflated with granular scales; interorbital area flat, canthus rostralis broadly rounded; snout less than half of the head length (SO/HL 0.39), less than twice as long as the orbital diameter (OD/SO 0.70); scales on the forehead, canthus rostralis and snout are homogeneous; scales from the posterior margin of the eyes to the nape are smaller than those of the forehead, somewhat blunt and juxtaposed; scales on the interorbital and occipital regions heterogeneous in size, without distinct tubercles; eye approximately one-quarter of the head length (OD/HL 0.27); pupil vertical with crenulate margins; supraciliaries moderate in size, blunt and hexagonal, those present in the mid-portion of the supraciliaries (above the orbit) are the largest and are more prominent; ear opening oval, obliquely orientated, small (EL/HL 0.09); eye to ear distance is less than the eye diameter (OE/OD 0.90); rostral wider than long (RL/RW 0.75), partially divided dorsally by a weakly developed rostral groove; single enlarged supranasal on either side, separated by two small internasals, about the same size as enlarged scales on the snout; rostral in contact with the first supralabials, nasals, two supranasals and an internasal; nostrils semicircular, openings laterally orientated, the posterior half covered by the nasal pad, each nasal is in broad contact with the rostral and surrounded by the supranasal, first supralabial, and three postnasals; two rows of scales separate the orbit from the supralabials; mental wider than long (ML/MW 0.64), triangular; two well developed postmentals on either side; the inner pair of postmentals almost twice the size of the outer pair (PMIIL/PMIL 0.64), bordered by the mental, infralabial I, the outer postmental and four gular scales; outer postmentals bordered by inner postmental, infralabials I and II, and four gular scales on either side; nine supralabials on each side, bordered by a row of large, flat, somewhat elongated scales; eight infralabials on each side, infralabials I to III are bordered ventrally by a row of enlarged gular scales, largest anteriorly; gular region with small granular scales throughout except for a few scale rows bordering the mental, postmentals and infralabials which are larger, flat and juxtaposed.

Body moderately slender, trunk length approximately half of the snout to vent length (TRL/SVL 0.48); dorsal scales heterogeneous, mostly small rounded granular scales, intermixed with irregularly arranged, enlarged tubercles (3–4 times the size of granular scales), bluntly conical and feebly keeled throughout, becoming more conical and slightly smaller towards the flanks, the largest on the sacral region; tubercles extend posteriorly from the occipital region to the second segment of the tail; tubercles on the nape are smaller than those of the dorsum; 21 mid-dorsal tubercle rows; 34 paravertebral tubercles between the level of the axilla and the level of the groin; ventrolateral folds are weakly developed, not denticulate but with a single row of continuous, projected smooth tubercles; ventral scales much larger than dorsals, smooth, cycloid, imbricate to subimbricate, slightly smaller in size under thighs; 39 mid-ventral scale rows; 12 distinct precloacal pores in a continuous series; a row of enlarged scales present below the precloacal pores bearing scales; two postcloacal tubercles on each side of the tail base.

Forearm (FL/SVL 0.15) and tibia (CL/SVL 0.17) short; digits narrow, without a scansorial pad, strongly inflected at each joint, all bearing robust, recurved claws; sub-digital lamellae transversely widened beneath the basal phalanx; basal lamellae 6–5–5–5–5 on the left manus, 5–5–6–6–4 on the right pes; distal lamellae (intervening rows of nonlamellar granular scales between the basal and distal lamellae series in parentheses): 6(2)–7(3)–9(2)–10(0)–7(2) on the left manus, 6(3)–9(1)–10(3)–9(3)–10(2) on the right pes; interdigital webbing absent from both the manus and pes; relative length of digits: I <V <II <III <IV on the right manus, I <II <V <III <IV on the right pes; scales on the palms and soles are smooth, weakly raised, subimbricate; scales on the forelimbs are heterogeneous in size, comprising flat, subimbricate scales on the upper arms, and those on forearms are heterogeneous in size, ventral portion covered with heterogenous sized imbricate scales; scales on the hindlimbs are heterogeneous in size, dorsal surfaces of the thighs and shanks have larger scales, intermixed with scattered, enlarged, conical, feebly keeled tubercles; anterior portion of thighs and ventral aspect of hindlimbs have enlarged, smooth, imbricate scales.

Tail incomplete, autotomised beyond the third post-pygal segment, oval in cross-section, dorsoventrally depressed; dorsal tubercles on the tail base (tail portion containing the hemipenes) are enlarged, flat, and weakly pointed; few enlarged, flat and distinctly keeled, tubercles randomly scattered on the first two segments of the tail, remaining dorsal caudal scales smooth, flat, heterogenous in size and shape; subcaudal scales distinctly larger than the dorsals, largest medially; enlarged paired subcaudals form a longitudinal row.

Colouration in life ( Fig. 6 ). Dorsum somewhat dark grey in colour; head is primarily dark brown with a few dirty white coloured patches towards the posterior end of the head; nape has distinct whitish blotches on the brown base colour; the mid-dorsum of the trunk has nine pairs of distinct dark brown blotches, each of the markings in a pair are parallel to each other, and bordered by whitish margins; hind limbs and forelimbs have indistinct cream coloured blotches or crossbars intermixed with black blotches. The attached segments of the tail have the same background coloration as the dorsum with a dark brown “w” shaped blotch on each segment. Ventral surface off white in colour.

Colouration in preservative ( Fig. 5 ; Appendix IV). The colour is pale in comparison to the live specimen. The dark spots on the dorsum have darkened to brownish-black.

Variation. Refer to Table 2 for morphometric and basic pholidosis variation within the type series of Cyrtodactylus agarwali sp. nov., comprising four adult males and one sub-adult male. The paratype series morphologically generally agree with the holotype description, but with the following exceptions: MZMU2157 has a higher number of PcP (18) in comparison to holotype (12) or other members of the type series (11–13).

Comparison. Cyrtodactylus agarwali sp. nov. is a member of the khasiensis group and differs from other members of lowland subclade within the Indo-Burman clade by an uncorrected p -distance of 6.5–22.6 % for the ND2 gene ( Fig. 2 ; Table 1 ). Cyrtodactylus agarwali sp. nov. is most closely related to Cyrtodactylus karsticola sp. nov. with 6.5% uncorrected p -distance ( Fig. 2 ; Table 1 ) but morphologically differs from the latter by having 11–18 PcP, N =5 (versus 34–38 PcFP, N =3); smaller, conical and closely spaced dorsal tubercles (versus relatively larger, flatter and sparsely placed dorsal tubercles).

Cyrtodactylus agarwali sp. nov. differs from the following species by having a smaller maximum adult size, SVL 71.8 mm, N =5 (versus C. kazirangaensis 80.0 mm, N =3; C. ayeyarwadyensis 78.0 mm, N =25; C. arunachalensis 81.7 mm, N =5; C.montanus 78.2 mm, N =5; C. jaintiaensis 96.2 mm, N =3; C. khasiensis 81.1 mm, N =7; C. martinstolli 82.0 mm, N =18; C. tamaiensis 90.0 mm, N =1; C. cayuensis 79.9 mm, N =18; C. urbanus 74.0 mm, N =7); from the following species by having a larger maximum adult size, SVL 71.8 mm, N =5 (versus 64.5 mm, N = 2 in C. himalayicus ; 65.2 mm, N =2, in C. septentrionalis ); from the following species by possessing 11–18 PcP, N =5 (versus 26–39 PcFP, N =8, in C. guwahatiensis ; 6–10 PcFP, N = 5 in C. arunachalensis ; 10–11 PcP, N = 3 in C. kazirangaensis ; 29–37 PcFP, N =11, in C. tripuraensis ; 10 PcP, N =2, in C. himalayicus ; 5+1 PcP, N =1, in C. mandalayensis ; 7 PcP, N =1, in C. markuscombaii ; 0–8 PcP, N =18, in C. martinstolli ; 40 PcFP, N =1, in C. tamaiensis ; 6–9 PcP, N =18, in C. cayuensis ; 6–10, N=5, in C. arunachalensis ); from the following species by having higher number of DTR, 21–25, N = 5 (versus 19-20, N =3, in C. jaintiaensis ; 16–18, N =2, in C. nagalandensis ; 18, N =1, in C. mandalayensis ; 14–15, N =2, in C. markuscombaii ); from C. septentrionalis by having lesser number of PVT (34–38, N =5 versus 38–42, N = 2 in C. septentrionalis ) from the following species by having enlarged plate like subcaudals absent, N =5 (versus present in C. khasiensis , N =7; C. martinstolli , N =18 and C. cayuensis , N =18); from the following species by having a different number of transverse series of blotches in the dorsum, 8–9, N =5 (versus 6–8, N =7, in C. urbanus ; 9–11, N =25, in C. ayeyarwadyensis ; 6–7, N =3, in C. kazirangaensis ; indistinct light and dark blotches forming longitudinal markings on neck and forebody, N =2, in C. nagalandensis ); from C. montanus by having a higher number of mid-ventral scale rows, 32–39, N =5 (versus 21–23, N =5); from C. himalayicus by scales posteriorly bordering the pore-bearing scale series are up to ca. 1.8 times enlarged relative to pore-bearing scales, N =5 (versus ca. 3 times larger than pore-bearing scales in C. himalayicus , N =2); from C. urbanus by the absence of a mid-dorsal stripe (versus present) and “V”-shaped PcP series, N =5 (versus “U”-shaped in C. urbanus , N =7).

Distribution and natural history ( Fig 1 . Appendix VII). The type series was collected from nearby Siju village from a rocky cave very close to a fast-flowing stream (Appendix 1). This species was also observed (but not collected) in and around limestone caves, and on loose soils in association with running hill streams. For a detailed description of the habitat and potential conservation issues at the Siju locality see the Distribution and natural history section of Cyrtodactylus karsticola sp. nov.

Etymology. The specific epithet agarwali is an eponym honouring Ishan Agarwal for his extensive and ongoing contributions in the field of systematics and taxonomy of Indian lizards, particularly geckos. The name is masculine and formed in the genitive case.

Suggested common name. Agarwal’s bent-toed gecko.

Figures

FIGURE 1. Elevation map showing the type localities of new species and Cyrtodactylus species included in the comparisons: 1. Cyrtodactylus karsticola sp. nov. (black star); 2. C. agarwali sp. nov. (black circle); 3. C. aaronbaueri sp. nov. (black triangle); 4. C. bengkhuaiai sp. nov. (black tilted square); 5. C. montanus; 6. C. tripuraensis; 7. C. khasiensis; 8. C. jaintiaensis; 9. C. guwahatiensis; 10. C. urbanus; 11. C. septentrionalis; 12. C. kazirangaensis; 13. C. nagalandensis; 14. C. arunachalensis; 15. C. markuscombaii and C. martinstolli; 16. C. himalayicus; 17. C. cayuensis; 18. C. tamaiensis; 19. C. ayeyarwadyensis; 20. C. mandalayensis.

FIGURE 2. Maximum Likelihood phylogeny of Indo-Burmese Cyrtodactylus; numbers at nodes represent bootstrap support (Preceding the species name is NCBI accession number and in the parenthesis is the museum catalogue number of the specimen).

FIGURE 5. A: Dorsal view, B: ventral view, C: details of dorsal pholidosis, D: dorsal view of head, E: ventral view of head and F: lateral view of head of the holotype of Cyrtodactylus agarwali sp. nov. (MZMU2160)

FIGURE 6. Live specimens of Cyrtodactylus agarwali sp. nov. (A: MZMU2157, B: uncollected specimens)

FIGURE 11. The arrangement of A: precloacofemoral pores in Cyrtodactylus karsticola sp. nov.; B: precloacal pores in Cyrtodactylus agarwali sp. nov.; C: precloacal pores in Cyrtodactylus aaronbaueri sp. nov.and D: precloacal pores in Cyrtodactylus bengkhuaiai sp. nov.