Hemidactylus paaragowli, Srikanthan & Swamy & Mohan & Pal, 2018

Srikanthan, Achyuthan N., Swamy, Priyanka, Mohan, Ashwini V. & Pal, Saunak, 2018, A distinct new species of riparian rock-dwelling gecko (genus: Hemidactylus) from the southern Western Ghats, Zootaxa 4434 (1), pp. 141-157 : 146-154

Hemidactylus paaragowli sp. nov.

Figs. 1–4

Holotype. CESL718 , adult male; collected from Ambanad Tea Estate , Agastyamalai , Tenmala Hills, Kollam District, Kerala, India (9.0410° N, 77.1155° E) on 4 June 2012 by S.R. Chandra Mouli.

Paratypes. CESL270 , adult female, CESL 271 , adult female, CESL 272 , adult male, CESL274 , adult female, CESL 267 , adult female; collected from Kanayar , Devarmalai-Sivagiri Hill Complex, Kollam District, Kerala, India (9.1249° N, 77.1736° E) on 23 May 2011 by Saunak Pal and Mrugank Prabhu ; CESL 127 , adult male collected from Achankovil , Kollam District, Kerala, India (9.1318° N, 77.1497° E) on 11 October 2009 by S.P. Vijaykumar.

Diagnosis. A large-sized gecko of the genus Hemidactylus , snout-vent length up to 124.4 mm; dorsum with heterogeneous pholidosis; 22-24 longitudinal rows of fairly regularly arranged, large, striated subtrihedral tubercles, nasals in contact with the rostral and the first supralabial, two pairs of well-developed postmentals, the inner pair longer than the outer, inner pair in contact with the mental, well defined ventrolateral folds, 33–39 ventral scale rows at the mid body, 10–12 femoral pores separated by 16–18 scales, original tail partially depressed with a median dorsal furrow, oval in section, three longitudinal rows of weakly keeled, striated, partially flattened tubercles on either side of the median dorsal furrow, dorsum with a longitudinal row of “I” shaped markings along the vertebra starting from the nape till the vent, white cross markings on the tail extending to black and white alternate bands on the tail at the tip.

Most of the Indian congeners namely H. garnotii Duméril & Bibron , H. platyurus (Schneider) , H. aquilonius McMahan & Zug , H. scabriceps (Annandale) , H. imbricatus Bauer, Giri, Greenbaum, Jackman, Dharne & Shouche , H. gracilis Blanford , H. reticulatus Beddome , H. albofasciatus Grandison & Soman , H. sataraensis Giri & Bauer , H. brookii Gray , H. gujaratensis Giri, Bauer, Vyas & Patil , H.frenatus Schlegel , H. persicus Anderson , H. robustus Heyden , H. parvimaculatus Deraniyagala , H. treutleri Mahony , H. gleadowi Murray , H. kushmorensis Murray , H. murrayi Gleadow , H. chipkali Mirza & Raju , H.triedrus (Daudin) , H. subtriedrus Jerdon , H. lankae Deraniyagala , H. depressus Gray , H. pieresii Kelaart , H.leschenaultii Duméril & Bibron , and H. flaviviridis Rüppel reach maximum SVL sizes of up to 90 mm and can be distinguished from this species with its large adult size (SVL upto 124 mm). Other congeners of H. paaragowli sp. nov. with adult SVL more than 90mm such as H. giganteus Stoliczka , H. aaronbaueri Giri , H. yajurvedi Murthy, Bauer, Agarwal, Lajmi & Giri, H. hemchandrai Dandge & Tiple, H. prashadi Smith , H. hunae Deraniyagala , H. graniticolus Agarwal, Giri & Bauer, H. maculatus Duméril & Bibron , H. acanthopholis Mirza & Sanap , H. kangerensis Mirza, Bhosale & Patil , H. sushilduttai Giri, Bauer, Mohapatra, Srinivasulu & Agarwal and H.vanam Chaitanya, Lajmi & Giri. are compared and the key distinguishing characters that set H. paaragowli sp.nov. apart from all large bodied congeners are as follows:

H. paaragowli possesses 22–24 longitudinal rows of fairly regularly arranged, large, striated subtrihedral, keeled tubercles in comparison with H.giganteus having no tubercles, H.yajurvedi , H.aaronbaueri and H.hemachandrai having slightly enlarged, weakly keeled dorsal tubercles H. prashadi having14–16 longitudinal rows of fairly regularly arranged, large, weakly keeled subtrihedral tubercles; H. maculatus having 20 longitudinal rows of fairly regularly arranged, large, striated trihedral, keeled tubercles; H. graniticolus having 16–18 longitudinal rows of fairly regularly arranged, large, striated subtrihedral, keeled tubercles; H. hunae having 16–20 longitudinal rows of regularly arranged, enlarged, subtrihedral, keeled tubercle; H.vanam having 17–19 rows of strongly keeled, heterogenous and striated tubercles, H. acanthopholis having 18–20 longitudinal rows of regularly arranged, large, striated trihedral, moderately keeled tubercle; H.kangerensis having 18–20 rows of keeled, trihedral enlarged tubercles and H.sushilduttai having 16–17 rows of strongly keeled trihedral enlarged tubercles.

The new species differs from the other large bodied congeners from the subcontinent by having 10–12 femoral pores on each side separated by 16–18 scales without pores as to H. prashadi having 17–20 femoral pores on each side separated by 3 scales without pores, H. maculatus having 16–19 femoral pores on each side separated by 5–9 scales without pores, H. graniticolus having 23–28 femoral pores on each side separated by 1–3 scales without pores, H.hunae by having 22–24 femoral pores on each side separated by 16–18 scales without pores, H. vanam having 17–22 femoral pores on each side separated by 10–11 scales without pores, H. kangerensis by having 18–21 femoral pores on each side separated by four poreless scales, H.sushilduttai by having 19–24 femoral pores on each side separated by four poreless scales and H. acanthopholis having 19–21 femoral pores separated by 13–14 scales without pores.

Description. Holotype is a well-preserved specimen that is dorsolaterally flattened, with the regenerated tail curved, an incision in the abdominal cavity made for extracting liver tissue for molecular analysis. A large-sized gecko with SVL 124.4mm and TL of 152.2 mm, slightly depressed head (HH/HL ratio 0.42) longer than wide with HW/HL ratio 0.75; concave loreal region with a slightly bulging canthus rostralis; relatively short snout (snout to eye/head width ratio 0.44) obtusely pointed; juxtaposed mixture of small and large granular scales on the snout, mostly large; rounded granular scales between the eye and the ear opening, slightly depressed tubercles above the ear opening, absence of ear lobules, ear opening suboval and slightly oblique, longer than wide, length of the ear opening almost half the orbital diameter (ear length/orbital diameter ratio 0.47); relatively small eyes (orbital diameter/head length ratio 0.20) with visible vertical pupils having notched borders; superciliaries rounded, some moderately pointed, anterior most being the largest; eye to ear distance longer than the optical diameter (eye to ear distance/orbital diameter ratio 1.52); nasal scale in contact with the rostral and the first supralabial; 4 small internasals between the supranasal scale and the first supralabials, Rostral wider than deep, 3–5 rows of scales separating the orbit from the supralabials, well developed mental triangle with well developed, large postmentals; 2 pairs of postmentals, outer pair about half the size of the inner pair, inner pair of postmentals bordered by the mental, first 2 infralabials and granular gular scales, a row of slightly longer gular scales bordering the postmentals that continue bordering along the infralabials, outer pair of postmentals in contact with the 3rd infralabial. Slightly enlarged rows of scales bordering the infralabials, 9 infralabials from angle to jaw on both left and right sides; supralabials 13—right and 11—left; gular scales subimbricate, smaller than ventral scales, gular scales on the anterior end and from the nape larger, smaller towards the gular region.

Relatively stout body, not elongate (TL/SVL ratio 0.44) with ventrolateral folds having no denticulations. Pholidosis of the dorsum heterogeneous with 22–24 rows of large, moderately keeled, subtrihedral, striated tubercles intermixed with granular and striated scales at the midbody, extending from the tail base till the occiput, enlarged tubercles smallest on the 2 mid dorsal parasagittal rows; enlarged tubercles roughly 4–6 times larger than the adjacent granular scales, rosettes of 14–16 granules surrounding every enlarged tubercle, each tubercle spaced from the other by 2–3 granular scales, increasing in size towards and stronger in keels towards the flanks; tubercles on the tail and the flanks larger in size and more strongly keeled than on the midbody.

Verticillate, depressed tail which is flat beneath, well defined dorsal median furrow, partially regenerated tail more than the SVL (TL/SVL ratio 1.24) covered with 10 depressed, weakly striated, posteriorly pointed, feebly keeled, enlarged tubercles on either side of the dorsal median furrow intermixed with smaller, posteriorly pointed, subimbricate scales, ventral scales of the tail larger, imbricate and has caudal plates, 12 femoral pores on the right and 10 femoral pores on the left side of the ventral part of the thighs, on a series of enlarged scales along the femur, separated by 18 pore less scales.

Scales on the palm smooth, rounded, granular, smaller than those on dorsal aspect of upper arm; striated, slightly conical, granular scales of the dorsal aspect of the upper arm intermixed with conical enlarged tubercles, thighs and shanks covered with granular, striated scales intermixed with striated enlarged subtrihedral tubercles extending till the posterior aspect of the thighs where the tubercles get smaller and eventually disappear; large striated scales covering the dorsal aspect of the feet.

Relatively short and stout limbs, short forearms (FL/SVL ratio 0.13), short tibia (CL/SVL 0.16) moderately short digits with strong claws; all digits of both the manus and pes feebly webbed; curved terminal phalanx in all the digits, angularly shaped and expands with the lamellar pad; toe scansors except the distal and basal scansors transversely divided found beneath each toe and finger in a transverse series, 10–11–10–11–11 on the right manus and 11–11–11–10 –9 on the right pes. Relative lengths of manus digits III (7.4)> IV (7.2) = II (7.2)>V (6.5)> I (5.1) and pes digits I (9.7)> II (8.9)> III (7.2)> IV (6.6)> V (4.9).

Coloration (in preservative). Dorsum greyish black with tubercles and granules marbled with white color, faded “I” shaped markings along the mid dorsal extending till the vent changing into x shaped crosses towards the tail, finely dotted and speckled labial scales, mottled with black and white, dirty white ventrum with the scales with fine black to dark brown dots in each scale, coloration from the dorsum fades into a dark to mild purple color towards the ventrolateral folds, ventral side of the limbs pale brown to dirty white while the dorsal aspect of the limbs follow the dorsal coloration of black with scattered white tubercles and granules, regenerated region of the tail unmarked with dark color, original tail reserving the x shaped crosses that eventually turns into black and white alternate bands. Ventral parts of the tail dirty white to creamish brown in with brown spots, caudal plates in the tail marbled with a light indigo coloration. Infralabials and supralabials in mild indigo to dark color, infralabials dotted with brown to black. Eyes dark blackish blue with a whitish pupil having crenulated margins.

Coloration (in life). Black dorsum with four large “I” shaped markings in yellowish white; some large tubercles colored in light yellow to white forming a subtle saddle shape on the sides of the middorsal markings; granules and tubercles in the dorsum between the dorsal markings light brown to yellow, finely dotted with minute black spots; limbs black on the dorsum with a mix of black and light yellow tubercles; two yellowish white stripe that runs on all the digits; the dorsal color fades into a dirty white color at the ventrolateral folds along the whole animal, including the limbs; head dark indigo to black in color with light yellow spots; a light brown snout with dark brown fine spots; some light yellow spots on supralabials and infralabials; dorsal “I” markings gradually turning into “X” shaped markings from the beginning of the tail and gradually changing into bands at the end of the tail. Tail banded with black and white.

Etymology. The species name is derived from the languages, Malayalam and Tamil. H. paaragowli sp. nov. is named after the habitat it inhabits, namely large rocks; paara means rock and gowli means gecko in both languages. ‘ Gowli ’ is derived from traditional South Indian mythological scriptures known as Gowli Shasthra; a set of superstitious beliefs based on where a falling gecko would land on a person. The specific epithet is formed as a noun in apposition. We conferred this name to this taxon for its predominant distribution in South India. We suggest the common name Travancore Rock Gecko for this species.

Variation in the type series. All the mensural and meristic data for the type series are given in the Table 4. The males range in SVL from 86.7mm to 124.4 mm (n=3) and females from 76.2 mm to 97.3 mm (n=3). The range of supralabials is 11–13 and 9–10 for infralabials. Scales across the venter range from 33–34 and a single specimen, CESL270 has 39 scales across the venter. CESL272 and CESL127 are male specimens with a femoral pore count of 10–12 separated by 16–18 poreless scales.

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Coloration of other specimens (preserved). Dorsum greyish black to brown with tubercles and granules marbled with white color, strong to faded “I” shaped markings along the mid dorsal extending till the vent changing into x shaped crosses towards the tail, finely dotted and speckled labial scales, mottled with black and white, dirty white venter with the scales with fine black to dark brown dots in each scale, coloration from the dorsum fades into a dark to mild indigo color towards the ventrolateral folds, ventral side of the limbs pale brown to dirty white while the dorsal aspect of the limbs follow the dorsal coloration of black with scattered white tubercles and granules, regenerated region of the tail unmarked with dark color, original tail reserving the x shaped crosses that eventually turns into black and white alternate bands. Ventral parts of the tail dirty white to creamish brown in with brown spots, caudal plates in the tail marbled with a light indigo coloration. Infralabials and supralabials in mild indigo to dark color, infralabials dotted with brown to black. Eyes dark blackish blue with a whitish pupil having crenulated margins.

Coloration of other specimens (in life). ( Figure 6 ) Black dorsum with three to four large “I” shaped markings in yellowish white; some large tubercles colored light yellow to white forming a subtle saddle shape (like H. graniticolus or H. maculatus ) on the sides of the mid-dorsal patterns; granules and tubercles in the dorsum between the dorsal markings in light brown to yellow, finely dotted with minute black spots; limbs black on the dorsum with a mix of black and light yellow tubercles; two yellowish white stripes that run on all the digits; the dorsal color fades into a dirty white color at the ventrolateral folds along the whole animal, including the limbs; head dark indigo to black in color with light yellow spots; a light brown snout with dark brown fine spots; some light yellow spots on supralabials and infralabials; dorsal “I” markings gradually turning into “x” shaped markings from the beginning of the tail and gradually changing into bands at the end of the tail. Tail banded with black and white. In juveniles, the lighter colors are brighter and dark colors darker when compared to the faded colors in the adults.

Phylogenetic relationships. Hemidactylus paaragowli is nested within the H. prashadi clade, with a high bootstrap value. Uncorrected P-distance of cytb dataset revealed a 17–25% divergence with other members of H.prashadi group, including its sister taxa H. vanam and H. acanthopholis

Distribution and natural history. The species was recorded from the low and mid-elevation regions of Devarmalai and Agasthyamalai hills, Kerala. In both the localities, this species was found to be fairly common. More then 10 individuals were repeatedly found to congregate on a single boulder at the type locality. In low elevation forests of Kanayar, Kollam district, Kerala, these geckos were observed to forage on crickets and other insects on boulders along stream in evening. It was found to be nocturnal and most individuals were observed on boulders in riparian habitats of lowland to mid elevation forests from 180 m to 800m (AMSL).

Figures

FIGURE 1. Full dorsal view of the holotype of Hemidactylus paaragowli sp. nov., CESL 718.

FIGURE 2. A) lateral, B) ventral and C) dorsal views of the head of the holotype of Hemidactylus paaragowli sp. nov., CESL 718.

FIGURE 3. A) Femoral pores, pes, B) manus and C) body dorsum of the holotype of Hemidactylus paaragowli sp. nov., CESL 718.

FIGURE 4. MP/ML tree of Indian Hemidactylus geckos constructed using cytb and ND2 mitochondrial and RAG1 and PDC nuclear sequences including H. paaragowli sp. nov.

FIGURE 6. Live individual (uncollected) of H. paaragowli sp. nov. A) dorsal and B) lateral views.