Hemidactylus giganteus Stoliczka, 1871

Kumar, Gandla Chethan, Srinivasulu, Aditya & Srinivasulu, Chelmala, 2022, Redescription of Hemidactylus giganteus Stoliczka, 1871 with the description of three new allied species (Squamata: Gekkonidae: Hemidactylus Goldfuss, 1820) from peninsular India, Zootaxa 5115 (3), pp. 301-341 : 307-316

Hemidactylus giganteus Stoliczka, 1871

( Figs. 4–7 ; Table 3 )

Syntypes: BMNH 1877.8 .6.5, adult male, Godavari valley , near Bhadrachalam, India; collected by W .T. Blanford; ZSI 2604 (female), ZSI 2605 (male)

Topotypes: NHMOU.REP.H63.2015, adult male; NHMOU.REP.H62.2015, adult male & NHMOU.REP.H61- 2015, adult female; Bhadrachalam (17.6687° N, 80.8935° E; 51 m a.s.l.), Bhadradri Kothagudem District , Telangana State, India; collected by Gandla Chethan Kumar, Krishna Prasad Kante & Devender Gundena, on 30th September, 2015 .

Common Name. Giant leaf-toed gecko / Giant rock gecko.

Diagnosis. A large-sized Hemidactylus (maximum SVL up to 136 mm; n =20). Dorsal pholidosis homogenous with more or less uniform, irregularly sized and shaped small granular scales. First supralabial in contact with nasal, but not in contact with nostril. Two well-developed pairs of postmentals, inner pair broadly in contact with each other and considerably larger than the outer pair. Ventrolateral folds indistinct, about 35–41 scale rows present across venter. Enlarged scansors on all digits, one to two proximal scansors and one distal scansor, undivided, rest divided; 11–13 (manus) and 10–12 (pes) divided scansors beneath first digit, 13–16 (manus) and 14–17 (pes) beneath fourth digit. 18–23 femoral pores on each thigh, separated by seven or eight poreless scales in males. 11–17 supralabials and 9–14 infralabials. Tail depressed, broadly swollen at the base, oval in transverse section without a median dorsal furrow; scales on the tail weakly imbricate, slightly larger than dorsals of body; ventral scales of tail large and imbricate, separated by medial row of transversely enlarged and regularly arranged subcaudal plates.

Comparison with congeners. Based on the general appearance, Hemidactylus giganteus sensu stricto is similar to H. yajurvedi and H. hemchandrai , but differs from the latter by femoral pores in males being 18–23 on each side of the thigh separated by seven or eight poreless scales (versus 10–12 femoral pores on each side separated by 5–8 poreless scales in H. yajurvedi , and 10 or 11 femoral pores on each side separated by five or six poreless scales in H. hemchandrai ). Dorsal pholidosis with irregularly sized and shaped granular scales (versus dorsum with small granules, intermixed with 10–12 rows of irregularly-arranged, slightly larger, rounded, weakly-keeled tubercles at midbody in H. yajurvedi ; and 12–15 rows of irregularly-arranged flattened to weakly conical tubercles on the dorsum in H. hemchandrai ).

The large size (SVL up to 136 mm) of H. giganteus sensu stricto distinguishes it from many other Indian congeners which are significantly smaller (SVL up to approximately 70 mm): H. albofasciatus Grandison & Soman ; H. aquilonius McMahan & Zug ; H. chikhaldaraensis Agarwal, Bauer, Giri & Khandekar ; H. chipkali Mirza & Raju ; H. flavicaudus Lajmi, Giri, Singh & Agarwal ; H. flaviviridis Rüppel ; H. frenatus Duméril & Bibron ; H. garnotii Duméril & Bibron ; H. cf. gleadowi Murray ; H. gracilis Blanford ; H. gujaratensis Giri, Bauer, Vyas & Patil ; H. imbricatus Bauer, Giri, Greenbaum, Jackman, Dharne & Shouche ; H. kushmorensis Murray ; H. leschenaultii Duméril & Bibron ; H. malcolmsmithi Constable ; H. murrayi Gleadow ; H. parvimaculatus Deraniyagala ; H. persicus Anderson ; H. platyurus Schneider ; H. reticulatus Beddome ; H. rishivalleyensis Agarwal, Thackeray & Khandekar ; H. sankariensis Agarwal, Bauer, Giri & Khandekar ; H. robustus Heyden ; H. sataraensis Giri & Bauer ; H. scabriceps Annandale ; H. treutleri Mahony ; H. turcicus Linnaeus ; H. varadgirii Chaitanya, Agarwal, Lajmi & Khandekar ; H. vijayraghavani Mirza ; and H. xericolus Lajmi, Giri, Singh & Agarwal.

The other large-bodied congeners can be distinguished on the basis of a suite of characters (differing or nonoverlapping characters indicated parenthetically): dorsal pholidosis homogenous with more or less uniform, irregularly sized and shaped small granular scales, and complete absence of dorsal tubercles in H. giganteus sensu stricto (versus enlarged dorsal tubercles, heterogenous, longitudinal rows of fairly regularly arranged, large, striated subtrihedral tubercles in H. aaronbaueri Giri ; H. acanthopholis Mirza & Sanap ; H. graniticolus Agarwal, Giri & Bauer ; H. hunae Deraniyagala ; H. kangerensis Mirza, Bhosale & Patil ; H. kolliensis Agarwal, Bauer, Giri & Khandekar ; H. maculatus Duméril & Bibron ; H. paaragowli Srikanthan, Swamy, Mohan & Pal ; H. prashadi Smith ; H. sahgali Mirza, Gowande, Patil, Ambekar & Patel ; H. sirumalaiensis Khandekar, Thackeray, Pawar & Agarwal ; H. siva C. Srinivasulu, A. Srinivasulu & Kumar ; H. sushilduttai Giri, Bauer, Mohapatra, C. Srinivasulu & Agarwal ; H. triedrus Daudin ; H. vanam Chaitanya, Lajmi & Giri ; and H. whitakeri Mirza, Gowande, Patil, Ambekar & Patel ).

Description (Based on topotype NHMOU. REP.H63.2015). The topotype is overall in good condition except the body shape is somewhat dorsoventrally flattened, tail is curved in a sigmoid manner, eyes are slightly sunken, all artefacts of preservation ( Fig. 4 ). Head short (HL/SVL ratio 0.28), slightly elongate (HW/HL ratio 0.78), not strongly depressed (HH/HL ratio 0.44), relatively broad (HW/BW ratio 0.74), distinct from neck ( Fig. 5A ). Loreal region is slightly inflated, canthus rostralis not prominent. Snout short (SE/HL ratio 0.44), longer than the eye diameter (SE/OD ratio 2.23). Scales on snout, canthus rostralis, forehead and interorbital region granular, homogeneous; scales on snout, canthus rostralis twice the size of those on the occipital, frontal and interorbital region ( Fig. 5A, B ). Eye small (OD/HL ratio 0.19); pupil vertical with crenate margins; superciliaries large, mucronate, pointed, slightly larger at the anterior end of orbit. Ear opening small, subcircular (greatest diameter 3.85 mm); eye to ear distance slightly greater than diameter of eye (EE/OD ratio 1.14). Rostral much wider (5.38 mm) than deep (2.58 mm); rostrum notched only near the apex; two enlarged supranasals separated by two smaller internasals; one postnasal on each side which is slightly smaller than internasal; a single smaller-sized postnasal on either side; rostral in contact with nostril and supralabial I. Nostrils large, slightly oval, each surrounded by supranasal, internasal, rostral, supralabial I, and postnasal. Mental enlarged, more or less triangular, slightly longer (6.08 mm) than wide (4.80 mm); two well-developed postmentals, the inner pair shorter (3.47 mm) than mental; outer pair more than half the size of the inner pair, separated from each other by inner pair; right outer postmental divided into two scales ( Fig. 5C ). Inner postmentals narrowly in contact, bordered by mental, infralabial I and II, outer postmental, and two gular scales; outer postmental bordered by inner postmental, infralabial II, and three left and four right gular scales. Supralabials (to midorbital position) 11 on either side; supralabials (to angle of jaw) 15 on either side; infralabials (to angle of jaw) 11 on either side.

Body relatively stout, trunk not elongate (TRL/SVL ratio 0.43), with indistinct ventrolateral folds and without denticulate scales. Dorsal pholidosis is homogenous with more or less uniform, moderately regularly sized and shaped small granular scales ( Fig. 6A ). Ventral scales much larger than those on dorsal, smooth, imbricate, subequal from chest to vent, slightly larger on precloacal and femoral region than on chest and abdominal region; midbody scale rows across venter 34–36; gular region with smaller, granular scales, posterior gular scales slightly larger than the rest ( Fig. 4B ). Femoral pores—23 (left) and 22 (right)—separated at mid-pelvic region by seven poreless scales (distinct diastema) ( Fig. 6B ). Scales on the palm and sole smooth, granular, rounded; scales on dorsal aspect of upper arm larger than granules on dorsum and subimbricate; posterior portion of forearm with much smaller, conical and granular scales; anterior portion with much larger, smooth, imbricate scales, continuing on the upper part of the hand. Scales on dorsal part of thigh and shank, similar to those on the dorsum, are granular with rounded tubercles, which are larger in size on thigh than on shank; the posterior aspect of the thigh lacks enlarged tubercles, while the anterior aspect have larger, smooth, imbricate scales.

Fore- and hindlimbs relatively stout; forearm short (FL/SVL ratio 0.16); tibia short (CL/SVL ratio 0.17). Digits moderately long, strongly clawed; digits I–IV of manus and pes indistinctly webbed; terminal phalanx of all digits curved, arising angularly from distal portion of expanded lamellar pad, half or more than half as long as associated toepad; scansors beneath each toe in straight transverse series, divided except a distal and three or four basal scansors on digit I and one or two in all digits; scansors from proximal-most at least twice the diameter of palmar scales to distal-most single scansor: 11-14-15-14-15 (left manus) and 11-14-14-14-14 (right manus), and 11-14-14- 15-14 (left pes) and 11-14-15-15-14 (right pes) ( Fig. 5D, E ). Relative length of digits (measurements in parentheses, in mm): IV (10.12)> V (9.84)> III (9.78)> II (8.89)> I (7.45) (right manus), and III (10.57)> V (10.23)> IV (9.96)> II (9.70)> I (7.06) (right pes).

Tail, regenerated, strongly depressed, broadly swollen at the base, flat beneath, verticillate, slightly shorter than the snout-vent length (TL/SVL ratio 0.78). Tail covered above with small uniform scales; ventral scales larger, imbricate, median row (subcaudal plate) slightly broader, not extending across width of the tail proximally, but distally they extend almost across the width of the tail ( Fig. 5F, G ). All the subcaudals arranged in a series.

Colouration in life ( Fig. 7c , 9 ). Dorsum brown to russet brown. Five irregular sets of wavy duller brown-grey bands transversely bordered by olive-black dots present between shoulder and sacrum. Fifth band starts at the distal end of the thigh, broader and incomplete, not adjoining the medial. The transverse bands are discrete, irregular in shape and size, and appear more or less wavy in shape with olive to black crenulations in the mid portions of the markings. A pale brown to light greyish brown mid-vertebral line is evident at the broadest portion of the body, situated medially between the transverse markings. The medial space between the transverse bands lighter, with black mottled markings distributed randomly all over the body. Occiput with horizontal band and two diagonal bands, discontinuous and blotched with dark grey-brown mottling at the edges. Crown with numerous light cream to grey blotches, irregular in size and shaped randomly arranged at the periphery and posteromedial portion of the interorbital and postorbital regions. Labials and infra-orbital regions are with pale greyish mottling. Limbs lighter russet brown with light brown annulations, irregular in size extending up to the digits. Digits with light greyish markings alternating with base colouration speckled along the limbs. Tail similar in colour and pattern to body dorsum, with pale grey markings interspersed with pale brown base colour with black margins at the edges. Regenerated portion of the tail paler compared to the body, with dark brown zig-zag patterns and mottling.

Colouration in preservative ( Fig. 4 ). The colouration of the dorsum is various shades of brown, from a light olive-brown to a deeper russet brown. The characteristic irregular wave shaped bands on the dorsum and tail are less prominent, faded in appearance towards the laterals. Mid-vertebral line is prominent and wheat-coloured. Bands on fore- and hindlimbs less prominent and appear faded. Original tail distinctly similar to the body with dark wheat brown colour. Regenerated portion of the tail is faded with no distinct markings.

Variation. The morphological data and mensural counts of the topotypic specimens ( Fig. 7A–C ) and other parts of the Telangana State ( Table 3 ) show individual variations. A total of 20 individuals (7 males and 13 females) ranged in SVL from 88.19 mm to 135.55 mm, with an average SVL of 115.31 ± 9.66 mm. Males were larger than females (121.02± 9.16 mm versus 112.93± 9.23 mm). In some older individuals, 2 regularly-arranged longitudinal rows of enlarged rounded tubercles at the flanks are present. Hemidactylus giganteus sensu stricto males from Telangana have a series of 18–23 femoral pores separated medially by a distinct diastema of seven or eight poreless scales .

Distribution. Based on the present study, the distribution of Hemidactylus giganteus sensu stricto is restricted to the Godavari river basin area of the Telangana State ( Fig. 8 ), and adjoining areas of Andhra Pradesh and Odisha. Earlier records of H. giganteus sensu lato from Andhra Pradesh, Maharashtra, Chhattisgarh, Karnataka, Tamil Nadu, and Kerala in Western Ghats ( Murthy 1985; Daniels 2000; Giri et al. 2003; Bansal & Karanth 2010; Srinivasulu et al. 2014) need to be confirmed and may represent putative new taxa. Pending taxonomic verification of these populations, we propose to provisionally refer to them as Hemidactylus cf. giganteus .

Natural history. Hemidactylus giganteus is largely a rupicolous leaf-toed gecko. It was encountered on rock boulders, in old forts, under culverts, in dilapidated buildings, and also in human habitation. It was also observed inhabiting the tree hollows of Banyan ( Ficus benghalensis ), Tamarind ( Tamarindus indicus ), Mango ( Mangifera indica ) and other tree species with large girth ( Fig. 9 ). In most of the localities it was found sharing its habitat with Hemidactylus cf. treutleri and Hemidactylus frenatus .

Figures

FIGURE 4. Hemidactylus giganteus sensu stricto (topotype, NHMOU.REP.H63.2015; adult male). A) dorsal view, B) ventral view. Photos by G. Chethan Kumar. Scale bar = 20 mm.

FIGURE 5. Hemidactylus giganteus sensu stricto (topotype, NHMOU.REP.H63.2015; adult male). A) dorsal view of head, B) lateral view of head, C) ventral view of head; D) ventral view of the right manus; E) ventral view of the right pes; F) dorsal view of the tail; and G) ventral view of the tail. Photos by G. Chethan Kumar. Scale bar = 10 mm.

FIGURE 6. Hemidactylus giganteus sensu stricto (topotype, NHMOU.REP.H63.2015; adult male). A) Details of dorsal pholidosis, B) Precloacal region of topotype (NHMOU.REP.H63.2015) showing a series of 23 femoral pores on left and 22 femoral pores on right side separated medially by eight poreless scales. Photo by G. Chethan Kumar. Scale bar = 10 mm.

FIGURE 7. Photographs of Hemidactylus giganteus sensu stricto. Topotypes—A) NHMOU.REP.H62.2015; adult male, B) NHMOU.REP.H61.2015; adult female, and live habitus C) adult male not collected. Photo by G. Chethan Kumar. Scale bar = 10 mm.

FIGURE 8. Map of peninsular India depicting the type locality (blue star) of Hemidactylus giganteus sensu stricto in Bhadradri Kothagudem District, Telangana State, India with currently known H. giganteus s. str. localities (blue circles) in Telangana State and Odisha; type locality (green star) of Hemidactylus raya sp. nov. in Bellary District, Karnataka, India with currently known H. raya sp. nov. localities (green circle) in Karnataka; type locality (red star) of Hemidactylus saxicolus sp. nov. in Raichur District, Karnataka, India with currently known H. saxicolus sp. nov. localities (red circles) in Karnataka and Telangana State; and type locality (pink star) of Hemidactylus aemulus sp. nov. in Nalgonda District, Telangana State, India with currently known H. aemulus sp. nov. localities (pink circles) in Telangana State. Distribution of H. hemchandrai (white star) and H. yajurvedi (yellow star and circles) are also depicted. Map prepared by Chelmala Srinivasulu.

FIGURE 9. Hemidactylus giganteus showing arboreal habit—A & B) adult individuals have often been sighted on trunks of large trees. Photo by G. Chethan Kumar.