Cnemaspis palakkadensis, Sayyed & Cyriac & Dileepkumar, 2020

Sayyed, Amit, Cyriac, Vivek Philip & Dileepkumar, Raveendan, 2020, A new cryptic species of Cnemaspis Strauch, 1887 (Squamata: Gekkonidae), in the C. littoralis complex, from Anakkal, Palakkad, Kerala, India, Amphibian & Reptile Conservation (e 251) 14 (3), pp. 31-45 : 34-38

Cnemaspis palakkadensis sp. nov.

Figs. 3–7 ; Tables 2 –4.

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Holotype. BNHS 2790 , an adult male, 32.2 mm SVL, from Anakkal (10°52’50”N, 76°39’23”E; ca. 140 m asl), Palakkad District , Kerala, south-western India ( Fig. 1 ), collected by Amit Sayyed, 18 May 2019.

Paratype. BNHS 2791 , an adult male, 31.5 mm SVL, and BNHS 2792 , an adult female, 34.1 mm SVL; collected from same locality as holotype by Vivek Vaidyanathan and Abhijit Nale, 19 May 2019 .

Diagnosis and comparison with Indian congeners. A small-sized Cnemaspis, SVL <35 mm; dorsal pholidosis homogenous with small, smooth, granular scales in the vertebral and paravertebral regions; conical or spine-like tubercles absent on flank; ventral scales smooth, imbricate; males with 15–16 femoral pores on each thigh and no pre-cloacal pores; supralabials to angle of jaw 7–8, infralabials to angle of jaw 6–8; lamellae under fourth digit of manus 12–15, and pes 14–17; tail without whorls of enlarged tubercles; median subcaudals enlarged, imbricate, smooth, post cloacal spur absent in both sexes.

Cnemaspis palakkadensis sp. nov. can be distinguished from all other Indian congeners on the basis of the following differing or non-overlapping characters: Spine-like tubercles absent on flanks [versus spine-like tubercles present on flank in C. amboliensis Sayyed, Pyron, and Dileepkumar , C. assamensis Das and Sengupta , C. anandani Murthy, Nitesh, Sengupta, and Deepak , C. flaviventralis Sayyed, Pyron, and Dahanukar , C. goaensis Sharma , C. gracilis (Beddome) , C. jerdonii (Theobald) , C. koynaensis Khandekar, Thackery, and Agarwal , C. monticola Manamendra-Arachchi, Batuwita, and Pethiyagoda , C. mysoriensis (Jerdon) , C. monticola Manamendra-Arachchi, Batuwita, and Pethiyagoda , C. nilagirica Manamendra-Arachchi, Batuwita, and Pethiyagoda , and C. otai Das and Bauer ]. Dorsal scales on midbody homogenous [versus heterogeneous in C. aaronbaueri Sayyed, Grismer, Campbell, and Dileepkumar , C. agarwali Khandekar , C. ajijae Sayyed, Pyron, and Dileepkumar , C. amba Khandekar, Thackery, and Agarwal , C. amboliensis , C. anamudiensis Cyriac, Johny, Umesh, and Palot , C. anandani , C. andersonii (Annandale) , C. australis Manamendra-Arachchi, Batuwita, and Pethiyagoda , C. avasabinae Agarwal, Bauer, and Khandekar , C. bangara Agarwal, Thackeray, Pal, and Khandekar , C. beddomei (Theobald) , C. chengodumalaensis Cyriac, Palot, and Deutiand Umesh , C. flaviventralis , C. girii Mirza, Pal, Bhosale, and Sanap , C. goaensis , C. gracilis , C. graniticola Agarwal, Thackeray, Pal, and Khandekar , C. heteropholis Bauer , C. kottiyoorensis Cyriac and Umesh , C. koynaensis , C. limayei Sayyed, Pyron, and Dileepkumar , C. maculicollis Cyriac, Johny, Umesh, and Palot , C. mahabali Sayyed, Pyron, and Dileepkumar , C. monticola Manamendra-Arachchi, Batuwita, and Pethiyagoda , C. nairi Inger, Marx, and Koshy, 1984 , C. ornata (Beddome) , C. shevaroyensis Khandekar, Gaitonde and Agarwal , C. sisparensis (Theobald) , C. thackerayi Khandekar, Gaitonde, and Agarwal , C. wicksii (Stoliczka) , C. yelagiriensis Agarwal, Thackeray, Pal, and Khandekar , and C. yercaudensis Das and Bauer ]. Presence of a series of 15–16 femoral pores on each side and the absence of pre-cloacal pores in males [versus absence of femoral pores in C aaronbaueri , C. anamudiensis , C. avasabinae , C. assamensis , C. beddomei , C. boiei (Gray) , C. maculicollis , C. nairi , and C. ornata ; presence of both pre-cloacal and femoral pores in C. adii , C. agarwali , C. amboliensis , C. andersonii , C. australis , C. bangara , C.gracilis , C. goaensis , C. graniticola , C. mysoriensis , C. otai , C. shevaroyensis , C. thackerayi , C. wicksii , C. yelagiriensis , and C. yercaudensis ]; and from the following species by presence large number of femoral pores [versus <10 femoral pores on each side in C. ajijae , C. amba , C. anandani , C. chengodumalaensis , C. flaviventralis , C. girii , C. heteropholis , C. indica , C. jerdonii , C. kottiyoorensis , C. koynaensis , C. limayei , C. mahabali , C. nilagirica , C. sisparensis , C. wynadensis , and C. zacharyi Cyriac, Palot, and Deutiand Umesh ; and a continuous series of precloacal-femoral pores in C. kolhapurensis ]. Median subcaudals enlarged [versus small median subcaudals in C. adii , C. ajijae , C. amba , C. andersonii , C. flaviventralis , C. girii , C. gracilis , C. koynaensis , and C. limayei ].

Cnemaspis palakkadensis sp. nov. could be confused with the morphologically similar C. littoralis (Jerdon) , but can be distinguished by its longer trunk length (AG 46–49% of SVL versus AG 37–46% of SVL in C. littoralis ); much smaller eyes (ED 13–14% of HL versus ED 16–21% of SVL in C. littoralis ); absence of conical or spine-like tubercles on flanks (versus small spine-like tubercles present on flanks in C. littoralis ); supralabials to angle of jaw 7–8 (versus 9–10 supralabials in C. littoralis ); number of scales between eye and tympanum 18–19 (versus 17); mid-dorsal scales 54–57 (versus 52); midventral scales 130–134 (versus 122); number of mid-body scales 32–38 (versus 26); absence of a small post-cloacal spur on both sides of the tail and absence of whorls of enlarged tubercles on the tail (versus a single post-cloacal spur present on each side of the tail and whorls of small but enlarged tubercles on the dorsal side of the tail in C. littoralis ).

Description of holotype. An adult male of SVL 32.2 mm ( Fig. 3A–B ); head moderately short (HL 17.6% of SVL), narrow (HW 15.9% of SVL), flat (HD 59.4% of HL), distinct from neck; snout short (E-S 78.6% of HL), slightly curved laterally; scales on snout granular, smooth, larger than those on the forehead and interorbital region ( Fig. 4A ); eye small (OD 21.8% of HL); pupil rounded; 13 supraciliaries; 30 interorbital scales; ear opening small (EL 5.7% of HL), longer than broad; 18 scales between eye and tympanum. Rostral wider than long, partially divided by a deep median groove; nostrils small, bordered posteriorly by two small, granular, postnasal scales; single enlarged supranasal on each side separated by an elongated intermediate scale. Mental large, triangular, not pointed posteriorly, broader than long, bordered posteriorly by two postmentals and a single intermediate chin shield broadly separated the postmentals, eight scales surrounded posteriorly by the posterior postmentals, infralabials, and the mental; three smooth, large scales posteriorly surrounded by intermediate chin shield; gular scales granular, smooth, larger than those on throat ( Fig. 4B ). Seven supralabials to angle of jaw on each side, supralabial I largest, decreasing in size posteriorly; six infralabials to angle of jaw on each side, infralabial I largest, decreasing in size posteriorly ( Fig. 4C ).

Body slender, short (TL 40%) without conical or spine-like tubercles on flanks ( Fig. 5A, C ). Dorsal scales of the body and flank homogenous, small, granular, smooth; scales on forehead, neck, and dorsal body equal in size; paravertebral scales 112; number of mid-dorsal scales 54; scales arranged in 33–35 longitudinal rows at midbody, number of midventral scales 131, smooth, imbricate, larger than dorsals ( Fig. 5B ). Fore and hind limbs relatively long, slender (FL 16.8%; TBL 16.4%); dorsal scales of brachium granular, smooth, larger than forearm; dorsal scales of forearm small, granular; ventral scales of brachium and forearm small, smooth; dorsal scales on palm, foot and fingers granular, smooth; scales on palmar and plantar surfaces smooth; subdigital lamellae entire, few fragmented; series of unpaired lamellae on basal portion of digits, separated from fragmented distal lamellae by a single large scale at the inflection; proximal lamellae series: 1-3-4-4-3 (right manus), 1-4-5-6-3 (right pes); distal lamellae series: 9-11-14-14-12 (right manus), 9-13-15-17-11 (right pes). Relative lengths of digits, fingers: IV (2.71 mm)> III (2.53 mm)> II (2.42 mm)> V (1.87 mm)> I (1.18 mm); toes: IV (3.68 mm)> III (3.16 mm)> II (1.99 mm)> V (1.75 mm)> I (0.85 mm) [ Fig. 6A–B ]. Femoral pores 15; 14 poreless scales between right and left femoral pore series; three rows of enlarged, roughly hexagonal scales above the femoral pores, larger than those on precloacal region; no precloacal pores; precloacal scales equal in size to the belly scales ( Fig. 6C ).

Tail long (TAL 111%), cylindrical, base swollen; post-cloacal spur absent on each side of lateral surface of hemipenal bulges at base of tail; dorsal scales of tail homogenous, smooth, granular, without enlarged, conical tubercles forming whorls, ventral scales imbricate, smooth; median subcaudals enlarged, smooth; those at the base are moderately smaller and imbricate ( Fig. 6D–F ).

Coloration in life ( Fig. 6A–C ). Male and female of the new species are the same in dorsal appearance. Dorsum of head mottled with brown and yellow; ventral side of head bright orange-yellow in males but white in females, bordered by a dark brown line up to the throat; nape with a small, black ocelli-like marking. Iris yellow with thin dark yellow line bordering pupil; pupil circular, black; supraciliaries yellow; supralabials and infralabials yellow. Dorsum of the body and limbs dull grey with brown and pale yellowish mottling; vertebral region pale yellow with 6–7 dark-edged lighter markings. Tail dull brown dorsally, with irregular faded yellow spots. Ventral side of body and tail white.

Coloration in preservative. Dorsum of the body and limbs with brown which turns into dark brown and pale yellow mottling and into grey; ventral side of body and tail greyish white; ventral side of head in males grey with slight yellowish tinge.

Variation of the type series ( Tables 1–3). The SVL of adult specimens in the type series of Cnemaspis palakkadensis sp. nov. (n = 3) ranges from 31.5 to 34.1 mm; number of posterior postmentals, 8–10; scales between eye and tympanum,18–19; number of interorbitals, 30–32; number of canthal scales, 14–15; number of dorsal paravertebral scales, 109–113; number of mid-dorsal scales, 54–57; number of midventral scales from mental to cloaca, 130–134; number of mid-body scales across belly, 32–38; lamellae under fourth digit of manus (MLamIV) and pes (PLamIV), 12–15 and 14– 17, respectively. Male and female paratypes match the holotype in overall coloration, except for the coloration on the throat.

Etymology. The specific epithet palakkadensis refers to the Palakkad district, from which the type series was collected.

Suggested Common Name. Palakkad Dwarf Gecko.

Distribution. At present, the new species is only known from the type locality in Anakkal reserve forest (10°52’50”N 76°39’23”E) in Palakkad District of Kerala state ( Fig. 1C ), which is a low-land moist deciduous to riparian forest at an elevation of 84–170 m asl on the northern border of the Palghat gap, a ca. 30-km gap separating the central and southern Western Ghats. However, it is possible that the range of this species may extend to other low-land forests in the Palakkad region of Kerala and Coimbatore of Tamil Nadu.

Natural history. The species is found in low-land moist deciduous to semi-evergreen forest habitat of Palakkad hills of the Central Western Ghats. The climate of the region is moist and humid, and the area is rich in natural forest. All the specimens were found active during the day on the trunks, branches, and exposed roots of large trees around small streams ( Fig. 8A–B ), suggesting that this species is arboreal and diurnal. Single eggs or pairs of eggs were observed in several tree holes during the field survey ( Fig. 7D ). Two eggs that were collected measured 5.1 × 4.9 mm and 5.2 × 5.0 mm. The types were found sympatrically with Ophiophagus hannah (Cantor) , Trimeresurus gramineus (Shaw) , Naja naja (Linnaeus) , Hypnale hypnale (Merrem) , Ahaetulla nasuta Lacepede , Amphiesma stolatum (Linnaeus) , Lycodon aulicus (Linnaeus) , Dendrelaphis tristis (Daudin) , Cnemaspis gracilis , Cnemaspis sp. , Psammophilus dorsalis (Gray) , and Psammophilus sp. (Stoliczka).

Figures

Fig. 3. Holotype (BNHS 2790) of Cnemaspis palakkadensis sp. nov. (A) Dorsal view and (B) ventral view of full-body. Photos by Amit Sayyed.

Fig. 4. Holotype (BNHS 2790) of Cnemaspis palakkadensis sp. nov. (A) Dorsal, (B) ventral, and (C) lateral views of the head. Photos by Amit Sayyed.

Fig. 5. Holotype (BNHS 2790) of Cnemaspis palakkadensis sp. nov. (A) Dorsal pholidosis at midbody, (B) ventral scales at midbody, (C) scales on lateral surface of trunk. Photos by Amit Sayyed.

Fig. 6. Holotype (BNHS 2790) of Cnemaspis palakkadensis sp. nov. (A) Lamellae on manus, (B) lamellae on pes, (C) femoral pores, (D) dorsal scalation of tail, (E) subcaudals, (F) lateral side of tail. Photos by Amit Sayyed.

Fig. 7. Color in life of Cnemaspis palakkadensis sp. nov. (A) Holotype male (BNHS 2790), (B) paratype female (BNHS 2792), (C) holotype male (BNHS 2790) showing the coloration of throat, (D) egg. Photos by Amit Sayyed.

Fig. 1. 16S rRNA tree of the Indian Cnemaspis obtained from the Maximum Likelihood analysis in IQ-TREE. Node values indicate bootstrap support with values <70 indicating low support, values between 70–90 indicating moderate support, and values> 90 indicating strong support. The blue and yellow circles represent the branches leading to C. littoralis and C. palakkadensis sp. nov., respectively, along with representative images of the two species indicated by their blue (C. littoralis) and yellow (C. palakkadensis sp. nov.) borders.

Fig. 8. Habitat of Cnemaspis palakkadensis sp. nov. Photos by Amit Sayyed.