Cyrtodactylus karsticola, 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 : 458-460

Cyrtodactylus karsticola sp. nov.

Figs. 3 , 4 , 11a ; Appendix III; Table 2

Holotype. Adult male ([ MZMU2155 ]; Figs. 3 ), from nearby a dirt road connecting National Highway 217 with the west bank of the Simsang River (25.355763°N, 90.690746°E; elevation 100 m a.s.l.), outskirts of Siju village, South Garo Hills District, Meghalaya state, northeast India, collected on 21 November 2020 by Yashpal Singh Rathee, Jayaditya Purkayastha, Sanath C. Bohra and Suraj Chauhan.

Paratypes. Two adult males ( MZMU2154 , MZMU2156 ), one adult female ( MZMU2153 ) same collection details as holotype (Appendix III) .

Definition. Cyrtodactylus karsticola sp. nov. is a moderate-sized gecko (adult SVL 63.7–70.7 mm); 10–11 supralabials; 9–10 infralabials; dorsal tubercles are rounded, bluntly conical and feebly keeled throughout, and are in 21–24 longitudinal rows; 34–39 paravertebral tubercles between the level of the axilla and the level of the groin; 35–39 mid-ventral scale rows; 34–38 precloacofemoral pores in males; scales posteriorly bordering the pore-bearing scale series are up to twice the size of pore-bearing scales; 13 pit bearing scales in precloacal series in females; 15–18 subdigital lamellae under IV toe; no single row of transversely enlarged subcaudal scales; dorsal markings are dark brown, irregular and distinct, somewhat parallel to each other and bordered by light body bands; tail with alternating dark and light bands.

Description of holotype ( Fig. 3 ). Holotype in generally good preservation condition; the abdomen shows signs of blistering and discolouration.

Adult male, SVL 63.9 mm. Head length slightly more than one-quarter of the snout to vent length (HL/SVL 0.28), longer than broad (HW/HL 0.63), somewhat depressed (HD/HW 0.58), and distinct from the neck; loreal region inflated with granular scales; interorbital region is flat; canthus rostralis broadly rounded; snout is less than half of the head length (SO/HL 0.39), less than twice as long as the orbit diameter (OD/SO 0.70); scales on the forehead, canthus rostralis and snout 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 without distinct tubercles. Orbit diameter is approximately one-quarter of the head length (OD/HL 0.27); pupil vertical with crenulate margins; supraciliaries small but distinct, somewhat blunt, median supraciliaries are the largest, decreasing in size anteriorly and posteriorly; ear opening small (EL/HL 0.08) oval, obliquely orientated; eye to ear distance is less than the eye diameter (OE/OD 0.86). Rostral slightly wider than long (RL/RW 0.85), 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, supranasals and internasals; nostrils semicircular, opening laterally orientated, posterior half covered by the nasal pad, each nasal in broad contact with the rostral and surrounded by a supranasal, first supralabial, and two postnasals; two rows of scales separate the orbit from the supralabials; mental wider than long (ML/MW 0.74), triangular; two well developed postmentals on either side, the inner pair almost twice the size of the outer pair (PMIIL/PMIL 0.58); inner postmentals in contact with the mental, infralabial I, one outer postmental and three gular scales; outer postmental on each side is in contact with one inner postmental, infralabials I and II, and three gular scales; ten supralabials on each side, bordered by a row of slightly elongated scales; nine infralabials on each side, infralabials I to IV bordered ventrally by a row of enlarged gular scales, largest anteriorly; gular region mostly covered with small granular scales except for a few rows bordering the mental, postmentals and infralabials which are larger, flat and juxtaposed.

Body moderately slender; trunk length is half of the snout to vent length (TRL/SVL 0.50); dorsal scales heterogeneous, mostly rounded granular scales, intermixed with irregularly arranged, enlarged tubercles (5–6 times larger than surrounding granular scales), bluntly conical and feebly keeled throughout, becoming more conical and slightly smaller towards the flanks, largest on the pre sacral and sacral regions; tubercles extend posteriorly from the occipital region to beyond the tail base; tubercles on the nape are smaller than those on the dorsum; 21 mid-body rows of dorsal tubercles; 39 paravertebral tubercles between the level of the axilla and the level of the groin; ventrolateral folds poorly developed with a single row of scattered conical enlarged, smooth tubercles; ventral scales much larger than dorsals, smooth, cycloid, imbricate to subimbricate, largest on the abdomen, slightly smaller under the thighs and on the region anterior to the cloacal opening; 35 mid-ventral scale rows; 38 precloacofemoral pores in a continuous series; scales posteriorly bordering the pore-bearing scale series are not enlarged relative to pore-bearing scales; three post cloacal tubercles on each side of the tail base.

Forearm (FL/SVL 0.15) and tibia (CL/SVL 0.18) short; digits laterally compressed, without a scansorial pad, strongly inflected at each joint, all bearing robust, recurved claws; subdigital lamellae transversely widened beneath the basal phalanx; basal lamellae 4–5–5–5–5 on the left manus, 4–5–6–7–5 on the left pes; distal lamellae (intervening rows of nonlamellar granular scales between basal and distal lamellae series in parentheses): 8(1)–9(2)–11(2)–11(2)– 10(1) on the left manus, 9(2)–10(3)–11(3)–11(3)–11(2) on the left pes; interdigital webbing absent from both the manus and pes; relative length of digits: I <V <II <III <IV on the left manus, I <II <V <III <IV on the left 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 the forearms are heterogeneous in size, ventral portion covered with heterogenous sized imbricate scales; scales on the hindlimbs are heterogeneous in size, on dorsal surfaces of thighs and shanks with small granular scales, intermixed with scattered, enlarged, conical, feebly keeled tubercles; anterior portion of the thighs and ventral surfaces of hindlimbs with enlarged, smooth, imbricate scales.

Tail (description based on specimen in life: tail not preserved) mostly original, complete, with a regenerated tip, slender, gradually tapering from the base to the pointed tip; poorly developed 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 quite large, smooth, imbricate, forming a mid-ventral series of enlarged paired scales; no transversely enlarged subcaudal plates.

Colouration in life ( Fig. 4 ): Dorsum of the head, body and limbs are dark brown; head is primarily dark brown in colour with a few yellowish patches towards the posterior end of the head; a small but distinct white streak is present on the posterior end of both orbits; nape has a few cream coloured spots on brown ground coloured blotches.. The dorsal markings consist of a pair of elongated dark brown blotches anteriorly, which break up posteriorly into six parallel pairs of smaller blotches. The tail was mostly complete with regenerate tip, having 11 distinct transverse greyish-brown bands separated by dark brown bands. The hind limbs and forelimbs are primarily brown with indistinct cream coloured blotches or crossbars. Ventral region is off white in colour.

Colouration in preservative ( Fig. 3 ; Appendix III): The colour is pale in comparison to the live specimen. The dark spots on the dorsum have turned brownish-black.

Variation. Refer to Table 2 for morphometric and basic pholidosis variation within the type series of Cyrtodactylus karsticola sp. nov., comprising three adult males and one adult female. MZMU2153 , the only female in the type series has a meshed dorsal blotch pattern rather than elongated blotches (Appendix III); scales posteriorly bordering the pore-bearing scale series are approximately twice the size of pore-bearing scales in MZMU2154 and MZMU2156 ; MZMU2153 , the only female paratype, has 13 pit-bearing scales in its precloacal series and no pitbearing femoral scales.

Comparison. Cyrtodactylus karsticola sp. nov. is a member of khasiensis group in the Indo-Burman clade ( Fig. 2 ), differing from other members of the clade by an uncorrected p -distance of 6.5–22.6% for the ND2 gene ( Table 2 ). Cyrtodactylus karsticola sp. nov. differs from the following species by having a smaller maximum adult size, SVL 70.7 mm, N =4 (versus C. kazirangaensis 80.0 mm, N =3; C. ayeyarwadyensis 78.0 mm, N=25; C. arunachalensis 81.7 mm, N =5; C. jaintiaensis 96.2 mm, N =3; C. montanus 78.2 mm, N = 5; C. khasiensis 81.1 mm, N =7; C. martinstolli 82.0 mm, N = 18; C. tamaiensis 90.0 mm, N =1; C. cayuensis 79.7 mm, N =18; C. urbanus 74.0 mm, N =7); from the following species by having a larger maximum adult size, SVL 70.7 mm, N =4 (versus 64.5 mm, N = 2 in C. himalayicus ; 65.2 mm, N =2, in C. septentrionalis ); from the following species by having a non-overlapping PcFP number, 34 –38 (versus 10–28 PcP/PcFP, N =25, in C. ayeyarwadyensis ; 8–10 PcP, N =5, in C. montanus ; 10–11 PcP, N =3, in C. kazirangaensis ; 10–12 PcP, N =7, in C. khasiensis ; 14 PcP, N =2, in C. septentrionalis ; 10 PcP, N =2, in C. himalayicus ; 5+1PcP, 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 ; 9–12 PcP, N =7, in C. urbanus ; 6–10 PcP, N= 5 in C. arunachalensis ); from C. arunachalensis by having a lower number of dorsal tubercle rows, DTR 21–24, N =4 (versus 24–26, N =5); from C. jaintiaensis by having a higher number of paravertebral tubercles, PVT 34–39, N = 4 (versus 30–34, N = 3); from the following species by having 13 pitted precloacal scales in females, N =4 (vs. 19–29 pitted scales, N = 11 in C.tripuraensis ; six depressions, N =2, in C. nagalandensis ); from the following species by having a higher number of MVSR 35–39, N =4 (versus 30–35, N = 8 in C. guwahatiensis ; 34–35, N = 2 in C. nagalendensis ; 30–34, N =7, in C. urbanus ); from C. kazirangaensis by having slightly lower number of supralabials, 10–11, N =4 (vs. 11–12, N =3); from the following species by having a higher number of DTR 21–24, N =4 (versus 18, N =1, in C. mandalayensis ; 14–15, N = 2 in C. markuscombaii ; 19–21, N = 11 in C. tripuraensis ); from the following species by the absence of enlarged plate like subcaudals, N =4 (versus present in C. khasiensis , N =7; C. martinstolli , N =18 and C. cayuensis , N =18); from C. himalayicus by scales posteriorly bordering the pore-bearing scale series are up to ca. 2x enlarged relative to pore-bearing scales N =4 (versus ca. 3x larger than pore-bearing scales, N =2, in C. himalayicus ).

Distribution and natural history ( Fig.1 ; Appendix VII.). This species is only known from the type locality and area surrounding Siju village ( Fig. 1 ). The type series was collected on 21 November 2020 from inside a limestone cave owned by a local villager several kilometres east of Siju village. Hatchlings and gravid females were also observed during this visit which were assumed to be conspecific with this species. Being a strictly nocturnal species, they are most active two to five hours after dark and are mostly seen in and around limestone caves, rocks, roots of large trees ( Ficus sp. ) and loose soils in association with running hill streams. The habitat is comprised largely of agricultural land with small patches of heavily disturbed secondary tropical evergreen forest.

Etymology. The specific epithet karsticola , is derived from the German noun “Karst” referring to a limestone landscape, and Latin suffix -cola meaning inhabitant of/dwelling in, with reference to the limestone cave habitat of the species.

Suggested common name. Karst dwelling 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 3. 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 karsticola sp. nov. (MZMU2155)

FIGURE 4. Live specimens of Cyrtodactylus karsticola sp. nov. (A and B are the dorsal and ventral view of the holotype; C and D are 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.