Dravidogecko douglasadamsi, 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 : 23-27

Dravidogecko douglasadamsi sp. nov.

( Figs 9 A–D, 13B, 14C; Table 6 )

Hoplodactylus anamallensis: Boulenger, 1885

Hoplodactylus anamallensis [non Gecko anamallensis Günther, 1875 ]— Boulenger, 1885 [partim]; Boulenger, 1890 [partim].

Dravidogecko anamallensis: Smith, 1933

Dravidogecko anamallensis [non Gecko anamallensis Günther, 1875 ]— Smith, 1935 [partim]; Murthy, 1993; Sharma, 2002 [partim].

Hemidactylus anamallensis: Bauer & Russell, 1995

Hemidactylus anamallensis [non Gecko anamallensis Günther, 1875 ]— Johnsingh, 2001; Srinivasulu, Srinivasulu & Molur, 2014 [partim]; etc.

Holotype. BNHS 2349 , an adult male, Manjolai (8.5514 °N, 77.3597 °E; ca. 1300 m asl.), Tirunelveli District , Tamil Nadu, collected by R. Venkitesan on 10 th June, 2017.

Referred specimens (Topotypes). BMNH 82.5.22.79, Adult female, BMNH 82.5.22.81, juvenile male, BMNH 82.5.22.80 & BMNH 82.5.22.82, Adult male—collected by Colonel Beddome from “Tinnevely” (now Tirunelveli) and deposited in the NHMUK.

Type locality. Manjolai, Tirunelveli District, Tamil Nadu.

Summarized description and diagnosis. Snout-vent length up to 48.5 mm (n=5); two pairs of well-developed postmentals, inner pair of comparable length to the outer postmentals and mental, bordered posteriorly by 2 or 3 gular scales; ventral scales counted at midbody, 31 or 32; precloacofemoral pores, 42 or 43; subdigital lamellae under digit IV of manus, 9 or 10 and under digit IV of pes, 10–12; supralabials 10–12 and infralabials, 8–10 on each side.

Dravidogecko douglasadamsi sp. nov. can be distinguished from other congeners based on the following characters: number of precloacofemoral pores (PcFP 40–43 versus 45 or 46 in D. anamallensis , 52–56 in D. septentrionalis sp. nov. & 36–38 in D. meghamalaiensis sp. nov.); postmentals of comparable length with mental ( ML /1PML 0.98–1.05 versus much longer, 0.74–0.81 in D. anamallensis ).

Genetic divergence (p-distance). Dravidogecko douglasadamsi sp. nov. is 11.0% –16.5% divergent from other previously described congeners.

Description of holotype. The holotype is in good condition ( Fig 9A ), except for an incision of about 2.1 mm at mid-trunk region, made to extract liver tissue. Posterior portion of tail curved in a sinusoidal manner, fifth finger on left forelimb curved upwards—both artefacts of preservation. Adult male, SVL 48.5 mm. Head short (HL/ SVL 0.27), slightly elongate ( HW /HL 0.64), slightly depressed (HH/ HW 0.57), distinct from neck. Loreal region slightly inflated, canthus rostralis indistinct ( Fig 9C ). Snout short ( SE /HL 0.36), longer than orbital diameter ( OD / SE 0.66); 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 9B ). Eye small ( OD /HL 0.24); pupil vertical with crenulated margins; supraciliaries small, rounded, directed outwards, increasing in size anteriorly. Ear opening elliptical (longer diameter 0.8 mm); eye to ear distance longer than diameter of eye ( EE / OD 1.19). Rostral wider than deep ( RL / RW 0.32), rostral groove absent; two large, roughly circular internasals, separated by two smaller, subequal scales, 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 two smaller scales 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; 2–4 rows of scales separate orbit from supralabials around mid-orbital position. Supralabials roughly rectangular, increasing in length anteriorly. Supralabials (to midorbital position) 9 (right), 9 (left); supralabials (to angle of jaw) 12 (right), 12 (left); infralabials (to angle of jaw) 10 (right), 10 (left). Mental triangular; two pairs of postmentals, smaller but roughly the same length as the mental; the inner pair slightly shorter (1.1 mm) than the mental (1.2 mm), and in strong contact with each other (0.7 mm) behind mental; outer pair shorter still (1.0 mm), separated from each other by two gular scales that are smaller than postmentals ( Fig 9D ). Inner postmentals bordered by mental, infralabial I, infralabials II (barely touching on right), outer postmentals and the two smaller gular scales that separate the outer postmentals; outer postmentals bordered by infralabials I (barely touching only on the left) and II, inner postmentals, and smaller gular scales each of dissimilar sizes, three on the right and four on the left sides. Body dorsoventrally flattened, relatively slender, elongate ( TRL / SVL 0.46). Dorsal pholidosis homogenous, composed of small, rounded granules 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, flat, rounded, juxtaposed scales; anteriormost gular scales visibly larger, flatter; scales on sacral and femoral regions larger than those on chest; precloacal scales largest; midbody scale rows across belly 31 or 32; Non-lamellar scales in the palmar and plantar regions heterogeneous in size, flat, rounded, juxtaposed on palm and sub-imbricate on sole; scales on dorsal aspect of upper arm much 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 0.12); 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: 6-8-9-9-7 (left manus), 6-8- 9-9-7 (right manus), 7-9-10-12 -9 (left pes), 7-9-10-12 -9 (right pes). Relative length of digits (measurements in mm in parentheses): IV (3.8)> III (3.6)> II (3.2)> V (2.6)> I (2.5) (left manus); IV (4.6)> III (4.5)> II (4.3)> V (3.8)> I (3.3) (left pes).

Tail entire, rounded at the base, flat beneath, tapering posteriorly, covered above uniformly with round, smooth, flat, sub-imbricate scales that become slightly larger laterally; pygal region containing the hemipenal bulge 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 43 precloacofemoral pores that are indistinct towards the knee ( Fig 13B ).

Variation in referred specimens. Internasals separated by one smaller scale in BMNH 82.5.22.83. Inner postmentals bordered posteriorly by three gular scales in BMNH 82.5.22.79 and BMNH 82.5.22.80. Outer postmentals bordered by 4 gulars on right and 5 on left in BMNH 82.5.22.79, BMNH 82.5.22.80, BMNH 82.5.22.83. Outer postmentals not in contact with infralabials in BMNH 82.5.22.80 (L), and in contact with both infralabials I and II in BMNH 82.5.22.79 and BMNH 82.5.22.83. Other morphological variations are listed in Table 6 .

Colouration in preservative. Dorsum uniformly brown, mottled with darker, discontinuous streaks from the snout to the base of tail ( Fig 9A ). Similar mottling faintly visible on dorsal aspect of limbs. Neck with a dark, discontinuous longitudinal streak, flanked at the break by two dark lines at a forty-five degree angle. Two discontinuous lines emanate from the eye, following the contour of the cranium posteriorly and extending beyond the forearm insertion. Inter-orbital region with a scattering of dark spots, witha 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 bordering each labial. A dark, roughly rectangular streak emanates from eye up to 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. Ventral region cream coloured with a scattering of two or three dark spots on each ventral scale. Ventral surface of tail pale, with scattered mid-brown speckling in the hemipenal region followed by alternating pale-dark bands in the distal half.

Colouration (in life) (based on photographs of an uncollected topotype). Dorsum mid-brown with faint, darker streaks throughout ( Fig 14C ). Head dorsum ground colour, snout slightly darker with a mottling of yellow scales throughout. A dark streak emanates from above the first supraocular and extends to the eye. Forehead with a scattering of spots that are either paler or darker. A longitudinal streak from the occiput extending into forehead, is flanked by a roughly inverted ‘V’ shaped marking posteriorly. Two dark spots follow, at and just beyond the forelimb insertion. Six irregular, roughly transverse markings follow, until the sacral region. Trunk with four or five rows of transversely arranged pale spots. Limbs of ground colour with irregular dark spots. Digits interspersed with yellow spots. Tail distinctly banded with alternating light and dark portions, more pronounced posteriorly.

Etymology. The specific epithet is a patronym honouring the English author and satirist, Douglas Noel Adams. Adams was also a renowned environmental activist. His radio documentary on critically endangered animals for the British Broadcasting Corporation (BBC) titled “Last Chance to See” and its accompanying book influenced the thinking of a whole generation of wildlife biologists. The etymology also alludes to the number ‘ 42 ’—the number of precloacofemoral pores that most specimens of this species possess. The number 42 incidentally is also the answer to the “ ultimate question of Life, The Universe and Everything ” according to Adams’ seminal book “The Hitchhikers Guide to the Galaxy”.

Suggested Common name. Adams’ Dravidogecko .

Distribution. Dravidogecko douglasadamsi sp. nov. is presently restricted in distribution to Manjolai and its environs in Tirunelveli district, south of the Shencottah gap in the southern Western Ghats. Similar habitats are seen in various parts of Kalakkad Mundanthurai Tiger Reserve, around which populations of this species might be found.

Habitat and natural history. The habitat in Manjolai and the adjoining Kalakkad- Mundanthurai forests where Dravidogecko is found, is chiefly comprised of southern- tropical semi-evergreen (700 m asl) and southern tropical wet evergreen forests (800–1500 m asl). These habitats receive an average annual rainfall of ca. 1600 mm ( Ayyanar & Ignacimuthu 2008). This species was seen occupying walls of a tea estate building during the night. There were no other geckos in sympatry, though a species of Eutropis was seen in the habitat during the daytime.

Figures

FIGURE 9. Holotype of D. douglasadamsi 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 14. A) Dravidogecko septentrionalis sp. nov. (BNHS 2344) in life, from Lakkidi village, Wayanad, Kerala B) Dravidogecko meghamalaiensis sp. nov. (BNHS 2347) in life from Meghamalai, Theni, Tamil Nadu C) Dravidogecko douglasadamsi sp. nov. (uncollected specimen) from Manjolai estate, Tirunelveli, Tamil Nadu

Tables

TABLE 6. Measurements (in mm) and scale counts for the holotype and paratypes of Dravidogecko meghamalaiensis sp. nov. and D. douglasadamsi sp. nov. Abbreviations as in Materials and Methods. * indicates tail is regenerated and #, a broken tail. Numbers in parentheses indicate the supralabial at midorbital position.

	Dravidogecko meghamalaiensis sp. nov.									Dravidogecko douglasadamsi sp. nov.
Tag	BNHS 2345	BNHS 2346	BNHS 2347	BNHS 2348	ZSIK 2976	ZSIK 2977	ZSIK 2978	ZSIK 2979	ZSIK 2980	BNHS 2349	82.5.22.81	82.5.22.79	82.5.22.83	82.5.22.80
Status	Holotype	Paratype	Paratype	Paratype	Paratype	Paratype	Paratype	Paratype	Paratype	Holotype	Topotype	Topotype	Topotype	Topotype
Sex	♂	♀	♀	♀	♀	♀	♂	♀	♂	♂	♂	♀	♂	♂
Measurements
SVL	45.1	45.5	43.3	48.7	47.8	44.1	41.5	42.0	43.8	48.5	25.7	47.1	29.0	34.6
TRL	21.9	21.0	20.1	23.1	24.6	21.0	17.2	17.8	19.2	22.6	10.3	22.7	13.3	16.0
BW	9.4	7.5	7.6	10.1	9.5	8.6	6.8	7.1	8.0	9.0	4.9	8.7	4.9	5.6
CL	6.1	6.2	5.7	6.4	6.4	6.2	5.1	5.4	5.8	6.2	-	6.7	-	-
TL	48.0	37.1*	47.9	52.0	42.8*	48.2	35.3*	3.6#	39.5*	64.1	-	34.5	-	-
TW	4.5	3.9	3.8	4.3	3.8	3.9	4.3	4.0	4.2	4.9	-	4.6	-	-
HL	12.6	12.3	12.1	13.1	12.8	12.0	11.6	11.6	11.9	13.3	7.8	13.9	8.9	9.9
HW	8.4	8.2	7.7	8.7	8.3	7.7	7.5	7.6	8.5	8.6	7.9	7.9	5.1	5.9
HH	4.7	4.4	4.6	4.7	4.6	4.5	4.1	4.5	4.8	5.0	2.5	4.4	3.1	3.3
FL	4.9	5.1	5.1	5.5	5.3	4.9	4.9	4.7	5.2	5.4	-	5.1	-	-
OD	2.8	2.7	2.6	2.8	2.8	2.9	2.7	2.5	2.7	3.2	-	3.3	-	-
NE	3.6	3.7	3.6	3.9	3.8	3.7	3.5	3.5	3.7	4.1	-	4.0	-	-
SE	4.9	4.9	4.7	4.9	4.9	4.8	4.5	4.4	4.7	4.9	-	4.8	-	-
EE	3.8	3.6	3.5	4.1	3.8	3.8	3.6	3.7	3.6	3.9	-	3.4	-	-
IN	1.7	1.7	1.6	1.7	1.7	1.7	1.6	1.5	1.7	1.8	-	1.3	-	-
IO	5.0	5.1	4.9	5.4	5.1	4.4	4.5	4.9	5.2	5.5	-	4.5	-	-
EL	0.8	0.5	0.5	0.5	0.6	0.4	0.4	0.5	0.4	0.8	-	0.4	-	-
RW	2.0	1.8	1.8	1.9	2.0	1.9	1.8	1.7	1.7	2.0	-	1.5	-	-
RL	0.6	0.8	0.6	0.7	0.5	0.7	0.6	0.6	0.7	0.6	-	0.7	-	-
ML	1.1	0.9	1.0	1.1	1.0	1.1	1.1	1.1	1.2	1.2	-	1.0	-	-
MW	1.5	1.6	1.5	1.8	1.6	1.6	1.5	1.6	1.7	1.7	-	1.5	-	-
CT	0.5	0.5	0.6	0.4	0.6	0.7	0.7	0.6	0.7	0.7	-	0.8	-	-
1PML	0.9	0.7	1.0	1.1	1.0	0.9	0.9	0.9	1.1	1.1	-	1.0	-	-
2PML	0.9	0.7	0.9	0.9	0.8	0.9	0.8	0.8	0.9	1.0	-	1.1	-	-
Meristics
PcFP	36	NA	NA	NA	NA	NA	38	NA	36	43	42	NA	42	42
VS	28-29	33-34	29-31	31-33	30-31	29-30	28-29	31-32	30-31	31-32	-	-	-	-
Lamellae (I-V)
Forelimb (L)	6-6-7-7-7	5-7-7-7-6	6-7-7-9-7	6-8-8-8-7	5-8-8-7-7	7-7-8-8-6	6-8-8-8-7	6-7-7-7-7	6-7-7-8-7	6-8-9-9-7	-	6-8-8-?-8	6-7-8-9-8	6-8-8-9-7
Forelimb(R)	6-7-7-7-6	5-7-7-7-6	6-7-7-9-7	7-7-8-8-6	6-7-7-7-7	7-7-8-8-7	6-8-8-8-7	6-7-7-7-7	6-8-8-8-6	6-8-9-9-7	-	7-8-8-9-8	6-8-8-9-8	6-8-8-10-7
Hindlimb (L)	6-7-8-9-7	5-7-8-9-8	6-8-9-9-7	5-8-9-9-7	6-7-9-10-8	6-8-8-9-7	6-7-8- 10-7	5-7-8-9-7	5-7-8-9-7	7-9-10- 12-9	-	6-9-10- 12-8	-	6-9-9-10-8
Hindlimb(R)	6-7-8-9-7	6-8-8-9-7	5-8-8-10-7	5-7-8-9-7	6-7-8-9-6	6-7-8-9-7	6-7-8- 10-7	5-7-7-9-8	5-7-8-9-6	7-9-10- 12-9	-	-	-	6-9-9-10-8
SL(L/R)	9(7)/9(6)	11(9)/9(6)	11(9)/11(8)	11(8)/11(7)	10(8)/10(8)	10(8)/10(8)	9(7)/10(7)	10(8)/10(8)	11(8)/10(7)	12(9)/12(9)	-	11(8)/10(8)	11(9)/10(8)	-
IL(L/R)	8/8	10/9	9/9	9/9	9/10	10/9	8/9	9/9	8/10	10/10	-	8/8	8/8	8/-