Dravidogecko smithi, Chaitanya & Giri & Deepak & Datta-Roy & Karanth, 2019

Chaitanya, R., Giri, Varad B., Deepak, V., Datta-Roy, Aniruddha & Karanth, Praveen, 2019, Diversification in the mountains: a generic reappraisal of the Western Ghats endemic gecko genus Dravidogecko Smith, 1933 (Squamata: Gekkonidae) with descriptions of six new species, Zootaxa 4688 (1), pp. 1-56 : 27-30

Dravidogecko smithi sp. nov.

( Figs 10 A–D, 13C, 15A; Table 7 )

Holotype. BNHS 2350 , an adult male, Ponmudi Hills (8.7570 °N, 77.1145 °E; ca. 920 m asl.), Tiruvananthapuram District , Kerala, collected by Jafer Palot and RC on 25 th November, 2017.

Paratypes. Details of collection same as the holotype. ZSIK 2981 , adult female .

Type locality. Ponmudi Hills, Tiruvananthapuram District, Kerala.

Summarized description and diagnosis. Snout-vent length up to 49.1 mm (n=2); one scale between internasals; two pairs of well-developed postmentals, inner pair longer than the outer but shorter than mental, bordered posteriorly by 2 or 3 gular scales; ventral scales counted at midbody, 29–32; precloacofemoral pores, 48 (n=1); subdigital lamellae under digit IV of manus, 8 or 9 and under digit IV of pes, 10 or 11; supralabials, 9 or 10 and infralabials, 7 or 8 on each side.

Dravidogecko smithi sp. nov. can be distinguished from other congeners based on the following characters: number of precloacofemoral pores (PcFP 48 versus 45 or 46 in D. anamallensis , 52–56 in D. septentrionalis sp. nov., 36–38 in D. meghamalaiensis sp. nov. & 42 or 43 in D. douglasadamsi sp. nov.); postmentals shorter in length than mental ( ML /1PML 1.07–1.12 versus longer, 0.74–0.81 in D. anamallensis ); one scale separating internasals (versus two in D. septentrionalis sp. nov.).

Genetic divergence (p-distance). Dravidogecko smithi sp. nov. exhibits 0.2% intraspecific variation for the mitochondrial ND2 gene, while it is 10.8% –17.0% divergent from all other congeners. Despite the proximity in range with D. douglasadamsi sp. nov. (straight line distance of ca. 50 kms), D. smithi sp. nov. exhibits 11.3% divergence from the former ( Table 9 ).

Description of holotype. The holotype is generally in good condition ( Fig 10A ). Hemipenes everted, and visible on both sides when viewed dorsally. Posterior half of tail regenerated, tip of which is curved upwards, fourth and fifth fingers on right forelimb curved upwards—both artefacts of preservation ( Fig 10A ). Adult male, SVL 49.1 mm. Head short (HL/SVL 0.27), slightly elongate (HW/HL 0.61), slightly depressed (HH/HW 0.55), distinct from neck. Loreal region slightly inflated, canthus rostralis indistinct ( Fig 10C ). Snout short (SE/HL 0.36), longer than orbital diameter (OD/SE 0.64); scales on snout, canthus rostralis, inter-orbital region, forehead, occipital and nuchal regions granular and rounded with those on the snout and canthus rostralis being larger ( Fig 10B ). Eye small (OD/HL 0.23); pupil vertical with crenulated margins; supraciliaries small, rounded, directed outwards, increasing in size anteriorly. Ear opening roughly elliptical (longer diameter 0.6 mm); eye to ear distance longer than diameter of eye (EE/OD 1.15). Rostral wider than deep (RL/RW 0.33), rostral groove distinct but extending only marginally downwards from the suturing with the internasals, medially; two large, roughly circular internasals, separated by a smaller scale, all in broad contact with rostral; two postnasals on either side, slightly smaller than the internasals, the lower in contact with supralabial I; rostral in contact with nasal, supralabial I, internasals and the smaller scale separating the internasals; nostrils about the size of the lower postnasal, roughly circular with nasal pad visible posteriorly; nasal surrounded by internasal, rostral, two postnasals and supralabial I on either side; 2 or 3 rows of scales separate orbit from supralabials around mid-orbital position. Supralabials roughly rectangular, increasing in length anteriorly. Supralabials (to midorbital position) 7 (right), 7 (left); supralabials (to angle of jaw) 9 (right), 9 (left); infralabials (to angle of jaw) 7 (right), 8 (left). Mental triangular; two pairs of smaller postmentals, the inner pair slightly shorter (1.0 mm) than the mental (1.2 mm), and in strong contact with each other (0.7 mm) behind mental; outer pair shorter still (0.8 mm), separated from each other by two gular scales that are smaller than postmentals ( Fig 10D ). Inner postmentals bordered by mental, infralabial I, outer postmentals and the two smaller gular scales that separate the outer postmentals; outer postmentals bordered by infralabials I and II, inner postmentals, and four smaller gular scales each of dissimilar sizes. Body dorsoventrally flattened, relatively slender, elongate (TRL/SVL 0.46). Dorsal pholidosis composed of small, rounded granules that are juxtaposed in arrangement throughout, becoming slightly larger at the lateral aspects; Ventral scales larger than dorsals, largely homogeneous in shape and size, smooth, flat, weakly pointed and sub-imbricate; gular region with smaller, granular, juxtaposed scales, anterior-most gular scales visibly larger, flatter; scales on sacral and femoral regions larger than those on chest; precloacal scales larger still; midbody scale rows across belly 31 or 32; Non-lamellar scales in the palmar and plantar regions heterogeneous in size, flat, rounded, sub-imbricate; scales on dorsal aspect of upper arm larger than granules on dorsum, flat, weakly pointed, sub-imbricate and smooth; dorsal aspect of forearm with smaller, sub-imbricate scales intermixed with a few rounded granules around the elbow; scales on dorsal aspect of hand and digits larger than those on forearm, flat, weakly pointed and imbricate; scales on anterior aspect of thigh large, flat, sub-imbricate and weakly pointed; rest of the dorsal scales on hindlimb smaller, granular and rounded. Scales on dorsal aspect of feet and toes larger than those on shank, flat, weakly pointed and imbricate.

Forearm (FL/SVL 0.11) and tibia short (CL/SVL 0.11); digits moderately short with relatively long terminal phalanges, strongly clawed; all digits of manus and digits I–IV of pes indistinctly webbed; terminal phalanx of all digits curved, arising angularly from distal portion of expanded lamellar pad, more than half as long as associated toepad; scansors beneath each toe undivided throughout, in a straight transverse series: 6-6-7-8-7 (left manus), 5-6- 7-8-8 (right manus), 6-8-9-10 -8 (left pes), 5-9-10-10 -8 (right pes). Relative length of digits (measurements in mm in parentheses): IV (3.9)> III (3.8)> II (3.3)> V (3.1)> I (2.7) (left manus); IV (4.7)> III (4.3)> II (4.0)> V (3.8)> I (3.2) (left pes).

Tail rounded at the base with distal half regenerated, flat beneath, tapering posteriorly, covered above uniformly with round, smooth, flat, sub-imbricate scales that become slightly larger laterally; basal portion of tail with six or seven rows of flat, weakly pointed, sub-imbricate scales; subsequent subcaudal scales larger, with an undivided median series of enlarged scales extending to tail tip. An uninterrupted series of 48 precloacofemoral pores, that are only faintly visible towards the knee ( Fig 13C ).

Variation in paratype. Rostral groove absent in ZSIK 2981 . Inner postmentals bordered posteriorly by three gular scales; outer postmentals bordered by 3 gulars on left in ZSIK 2981 . Other morphological variations are listed in Table 7 .

Colour in preservative. Dorsum uniformly greyish-brown, mottled with darker, discontinuous horizontal streaks in the trunk ( Fig 10A ). Similar mottling faintly visible on dorsal aspect of limbs. Occipital region with a dark, longitudinal streak, flanked anteriorly by two dark spots. Two discontinuous lines emanate from the eye, breaking posteriolaterally at the head, following the contour of the cranium laterally and extending beyond the forearm insertion. Inter-orbital region with a scattering of dark spots, with a distinct dark blotch bordering the supraciliary region on either side. Labials paler than the rest of the head with a faint, pattern-less scattering of darker spots on each labial. A dark, roughly rectangular streak emanates from eye upto the region above the third supralabial on the right side and the nostril on the left. Limbs no different from rest of the dorsum. Tail of similar ground colour to dorsum with alternating pale-dark longitudinal bands, the first of which is roughly saddle-shaped, up to the regenerated portion. Regenerated portion of tail uniformly greyish throughout with a scattering of darker longitudinal streaks. Ventral region cream coloured with a scattering of three to five dark spots on each ventral scale. Ventral surface of tail pale, with scattered mid-brown speckling in the hemipenial region followed by alternating pale-dark bands up to the regenerated portion.

Colouration (in life). Dorsum mid-brown in life ( Fig 15A ). Distinct yellow blotches visible across dorsal aspect of head, trunk and original portion of tail. Snout predominantly yellow. Lateral aspect with a series of pale yellow spots. Iris dark green with darker venations. Pupil black, with indistinctly crenulated margins. Other patterns and markings in accordance with the description of colour in preservative.

Etymology. The specific epithet is an eponym honouring British herpetologist Malcolm Arthur Smith for establishing the genus Dravidogecko in the year 1933. His seminal work on Indian herpetology, resulting in the text “The fauna of British India, including Ceylon and Burma ” in three volumes, is still considered the bedrock of reptilian taxonomy in India.

Suggested Common name. Smith’s Dravidogecko .

Distribution. Dravidogecko smithi sp. nov. is currently restricted in distribution to the Ponmudi Hills in Thiruvananthapuram District, Kerala. The habitat chiefly constitutes tropical evergreen rainforests ( Champion & Seth 1968). The Agastyamalai Hill Range just south of Ponmudi has similar habitats in which Dravidogecko might be found.

Habitat and natural history. The type-series of Dravidogecko smithi sp. nov. was collected in the Ponmudi Hills at an altitude of ca. 900 m asl. These geckos are found occupying human structures that are scattered along the road to the Ponmudi Hills. Other lizards found in sympatry with Dravidogecko in the region were Hemidactylus cf. frenatus , Cnemaspis sp. and Eutropis cf. carinata , which was also abundant in the adjoining shola grasslands.

Figures

FIGURE 10. Holotype of D. smithi sp. nov. A) Full-body dorsal B) Head dorsal C) Head lateral D) Head ventral. Scale bar = 10 mm.

FIGURE 13. Cloacal region showing precloacofemoral pores (indicated by black dots) in the congeners of Dravidogecko. A) D. anamallensis B) D. douglasadamsi sp. nov. C) D. smithi sp. nov. D) D. meghamalaiensis sp. nov. E) D. janakiae sp. nov. F) D. septentrionalis sp. nov. G) D. tholpalli sp. nov. Scale bar = 10 mm

FIGURE 15. A) Dravidogecko smithi sp. nov. (BNHS 2350) from Ponmudi, Tiruvananthapuram, Kerala B) Dravidogecko tholpalli sp. nov. (uncollected specimen) from Kodaikanal town, Dindigul, Tamil Nadu C) Dravidogecko janakiae sp. nov. (uncollected specimen) from Munnar, Idukki, Tamil Nadu.