Dravidogecko Smith, 1933

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 : 11-14

Genus: Dravidogecko Smith, 1933

Type-species. By monotypy— Gecko anamallensis Günther, 1875 .

Summarized generic description & diagnosis. (N=48). Small sized geckos (average SVL 48.0 mm ± 6.2) that are dorsoventrally compressed ( Fig 4A )and elongate (average TRL/SVL 0.47); dorsal pholidosis homogenous and devoid of enlarged tubercles—composed of small, rounded granules throughout; scales on snout and canthus rostralis larger than rest of head; eye with a vertical pupil possessing crenulated margins; ear opening elliptical or sometimes round; internasals divided by one or two smaller scales; two postnasals on either side; rostral wider than deep, usu- ally without a median groove; supralabials 8–12 and infralabials 7–10 on each side, roughly rectangular; ventral scales flat, weakly pointed and sub-imbricate, 24–35 when counted at midbody; mental wider than long, triangular; two pairs of well-developed postmentals, inner pair usually longer than the outer and in strong contact with each other behind the mental; digits moderately short with relatively long, strongly clawed terminal phalanges that are curved and arise angularly from the distal portion of expanded lamellar pad; scansors beneath each digit undivided throughout ( Fig 4C ), in a straight transverse series, 7–10 under digit IV of manus and 9–13 under digit IV of pes; an uninterrupted series of 35–56 precloacofemoral pores that usually extends up to the knee ( Fig 4B ); females with enlarged lymphatic sacs.

Osteology. Among the median dorsal skull elements, the parietals and nasals are separate. The premaxillae are fused and form a kite shaped pre-nasal process extending between the nasals ( Fig 5A ). Frontals fused, pineal foramen absent. A boomerang shaped post-frontal on each side, along the suture between the frontals and parietals. Post-frontals distinctly detached from the frontoparietal margins. Orbits bordered anteriorly by crescent shaped pre-frontals. The base of orbit is partially formed by the jugal, palatine, transpalatine and pterygoid bones. Pterygoids widely separated from one another. Each pterygoid is connected to the parietals by an upwardly extending epipterygoid. Endolymphatic sacs in females enlarged extracranially and extend to the level of the sixth vertebra. The hyoid and only the first branchial arch persist ( Fig 5B ). Anterior end of ceratobranchial I is separated from the basihyal and appears to lie free in the surrounding muscle. There are twenty-six presacral vertebrae, including three anterior cervical vertebrae without associated ribs and one lumbar vertebra. Two sacral, five pygal and 21.5 caudal vertebrae and a slightly curved, elongate precloacal bone on either side that extends up to the first pygal vertebra. Eight premaxillary teeth and approximately 35 teeth on each maxillary bone, 40 on each dentary. Phalangeal for- mulae 2-3-4-5-3 for manus and 2-3-4-5-4 for pes with the antepenultimate phalanx highly reduced in digits 3, 4 in manus and 3, 4 and 5 in pes ( Fig 5C ).

Distribution. The genus is endemic to the Western Ghats mountain range in peninsular India. The distribution presently extends from Ponmudi, Tiruvananthapuram district in the south (8.75°N, 77.11°E) to Vythiri, Wayanad district in the north (11.54°N, 76.03°E), both from Kerala. Their eastern-most distribution is up to the Meghamalai Hills (9.69°N, 77.39°E) in Tamil Nadu. These nocturnal, chiefly arboreal geckos are restricted to moist-deciduous and evergreen forests and can be found on trees, under rocks during the day or willingly occupying uninhabited man-made structures in these landscapes. They are restricted to mid–high elevations of the Western Ghats (ca. 850 m– 2000 m above mean sea level, m asl) in the southern Indian states of Tamil Nadu and Kerala.

Etymology. Smith (1933) does not explain the etymology of the generic epithet Dravidogecko which could be assumed to be composed of two words. The stem word, ‘ dravido ’ is possibly derived from the Sanskrit “ dravid ” (pronounced /ðrävid/) for “land surrounded by water on three sides”—an allusion to peninsular India. The generic nomen therefore, is possibly a reference to the restricted distribution range of these geckos in peninsular India. The gender of the genus is designated as masculine herein (fide ICZN 1999: Article 30.2.1).

Suggested common name. We recommend retention of the generic epithet Dravidogecko as the common name for this genus owing to its endemism to the Western Ghats in Peninsular India. The common name “Anaimalai gecko” has been used in the past ( Palot 2015) since D. anamallensis was the only nominal species in the genus. This name misrepresents the extent of distribution of these geckos and therefore should not be used hereafter.

Figures

FIGURE 4. A) In-situ photograph of an uncollected specimen of D. anamallensis B) Cloacal region showing precloacofemoral pores in an uncollected specimen of D. anamallensis C) Undivided lamellae on the right manus of D. septentrionalis sp. nov.

FIGURE 5. Osteological characters in Dravidogecko as seen in D. septentrionalis sp. nov. A) Full body dorsal; B) head ventral showing the hyoid apparatus (arrow points at first ceratobranchial arch); C) Right pes showing phalangeal arrangement (arrow points at the highly diminutive ante-penultimate phalange on digits 3,4 and 5).