Hemidactylus flavicaudus, Lajmi & Giri & Singh & Agarwal, 2020

Lajmi, Aparna, Giri, Varad B., Singh, Taneraw & Agarwal, Ishan, 2020, Two new species of yellow-tailed Hemidactylus Goldfuss, 1820 (Squamata Gekkonidae) from rocky outcrops on the Telangana Plateau, India, Zootaxa 4895 (4), pp. 483-504 : 487-492

Hemidactylus flavicaudus sp. nov.

Figs. 2–5 , Table 3

Holotype. National Centre for Biological Sciences (NCBS) NRC-AA-1105, adult female; collected from near Guddeguda village , Mahabubnagar District, Telangana, India (16.68069° N, 77.82587° E, 416 m asl) on 22August 2015 by Aparna Lajmi, Aniruddha Datta Roy, Deepak Veerappan and Praveen Karanth.

Paratypes. CES 17028 adult female, CES 17029, CES 17031 adult males (same collection data as holotype); NRC-AA-1106, NRC-AA-1108, adult females (same collection data as holotype except collected on 20 April 2015 by Aparna Lajmi , Taneraw Singh and Maitreya Sil ; NRC-AA-1107, CES 16129 adult females, NRC-AA-1109 adult male collected from Manyamkonda , Mahabubnagar District , Telangana , India (16.6504° N, 77.888° E, 560 m asl) on 20 April 2015 by Aparna Lajmi , Taneraw Singh and Maitreya Sil.

Etymology. The specific epithet is an adjective derived from the Latin flavus (= yellow) and cauda (= tail), for the yellow tail of the new species.

Suggested common name. Mahabubnagar yellow-tailed brookiish gecko

Diagnosis. A small sized Hemidactylus , snout-vent length up to at least 41.8 mm (n=9). Dorsal pholidosis heterogeneous composed of subcircular granular scales intermixed with moderately enlarged, circular, flattened, feebly keeled tubercles extending from occiput to tail and in 11–14 irregularly arranged longitudinal rows at midbody. Ventrolateral folds indistinct, about 22–26 scale rows across venter. Digits with slightly enlarged, divided scansors; lamellae in oblique series, six or seven (manus) and seven or eight (pes) beneath fourth digit and four (manus) and four or five (pes) beneath first digit; 15–17 precloacofemoral pores on each side separated by one or two poreless scales in males (n=3). Original tail slightly depressed, verticillate, oval in transverse section with indistinct median dorsal furrow; dorsal tail pholidosis heterogenous with rounded, smooth, subimbricate scales intermixed with two to three enlarged, conical keeled tubercles at the base of every whorl, on either side of median dorsal furrow; subcaudals much enlarged; a pair of slightly enlarged postcloacal spurs on either side. Dorsal colouration of transversely arranged, pale grey to ashy markings on a pale, mustard-brown background; thick nuchal collar which fuses with postorbital streaks laterally. Tail distinctly yellow in adults of both sexes and juveniles.

Comparison with other members of the H. brookii group. Hemidactylus flavicaudus sp. nov. can be distinguished from all other members of the Indian radiation, except H. xericolus sp. nov. based on its conspicuous yellow tail. It can be further distinguished from many members of the H. brookii group by its small adult size (maximum SVL 41.8 mm versus 55.8 in H. brookii , 51.5 mm in H. chikhaldaraensis Agarwal, Bauer, Giri & Khandekar , 74.2 mm in H. chipkali Mirza & Raju , 56.2 mm in H. cf. gleadowi , 51.4 mm in H. kushmorensis , 65.0 mm in H. murrayi ( Lajmi et al. 2016) , 53.8 mm in H. malcolmsmithi (Constable) , 52.3 mm in H. parvimaculatus Deraniyagala ( Lajmi et al. 2016), 62.5 mm in H. rishivalleyensis Agarwal, Thackeray & Khandekar , 50.8 mm in H. sankariensis Agarwal, Bauer, Giri & Khandekar , 61.7 mm in H. subtreidroides , 70.2 mm in H. treutleri Mahony , and 61.9 mm in H. varadgirii Chaitanya, Agarwal, Lajmi & Khandekar ). Hemidactylus flavicaudus sp. nov. can be distinguished from the species that are less than 55 mm SVL by the presence of moderately enlarged, flattened, feebly keeled dorsal tubercles in 11–14 irregularly arranged rows versus strongly enlarged and keeled, pointed tubercles in 15–17 fairly regularly arranged longitudinal rows in H. chikhaldaraensis ; enlarged and keeled conical dorsal tubercles in 19 or 20 fairly regularly arranged longitudinal rows in H. kushmorensis ; slightly enlarged, keeled, conical tubercles in 15–20 fairly regularly arranged longitudinal rows in H. malcolmsmithi ; slightly enlarged, keeled, conical tubercles in 15–18 fairly regularly arranged longitudinal rows in H. parvimaculatus ; strongly enlarged and keeled, pointed tubercles in 15 fairly regularly arranged longitudinal rows in H. sankariensis . The new species can be easily distinguished from members of the ground dwelling clade by the presence of 15–17 precloacofemoral pores on each side in males (versus less than eight precloacal pores in males of H. albofasciatus Grandison & Soman , H. gracilis Blanford , H. imbricatus , H. reticulatus Beddome , H. sataraensis Giri & Bauer and H. vijayraghvani Mirza ). Hemidactylus flavicaudus sp. nov. can be distinguished from H. gleadowi by the lower number of scales across the belly (22–26 versus 32–34) and fewer dorsal tubercle rows (11–14 versus 17 or 18). The yellow colouration of the tail in life as well as the dorsal colour pattern are unique among Indian Hemidactylus except for Hemidactylus xericolus sp. nov., the diagnosis against which is in the species description.

Holotype description. The holotype is generally in good condition with some minor exceptions; all artefacts of preservation: the body shape is somewhat dorsoventrally flattened, the partly regenerated tail is curved in a sigmoid manner towards the right. Head short (HL/ SVL 0.28), slightly elongate ( HW /HL 0.70), not strongly depressed (HH/ HL 0.39), relatively broad ( HW / BW 0.82), distinctly broader than neck. Loreal region slightly inflated, canthus rostralis not prominent. Snout short ( SE /HL 0.44); slightly longer than eye diameter ( OD / SE 0.54); scales on the snout, canthus rostralis and forehead region homogeneous in shape and slightly heterogeneous in size, rounded, flat and juxtaposed; distinctively larger than those on interorbital and occipital region; scales on interorbital and occipital region homogeneous in shape, slightly heterogeneous in size, granular, those on occipital region smallest. Eye small ( OD /HL 0.24); pupil vertical with crenate margins; supraciliaries small, mucronate, increasing in size from mid-orbital position with those on the anterior end of orbit largest. Ear opening oval (greatest diameter 1.00 mm); eye to ear distance greater than eye diameter ( EE / OD 1.30). Rostral wider (1.6 mm) than deep (0.9 mm), completely divided dorsally by weakly developed rostral groove; two enlarged internasals in contact medially, one supranasal on each side which is half the size of internasal; two postnasals on either side, slightly smaller than supranasal; both postnasals on right side are of similar size; on left, lower postnasal is smaller than the upper; rostral in contact with nasal, supralabial I and internasal; nostrils large, slightly oval, directed upwards, covering most of the nasal scale; nasal on either side surrounded by supranasal, internasal, rostral, supralabial I and postnasals. Mental almost equal in length (1.8 mm) and width (1.7 mm) triangular, two well-developed postmentals, the inner pair slightly shorter (1.4 mm) than mental and narrowly in contact with each other (0.5 mm) behind mental, outer pair slightly smaller (1.0 mm) than the inner pair, separated from each other by inner pair. Inner postmentals bordered by mental, infralabial I, barely infralabial II, outer postmental and four gular scales; outer postmental bordered by inner postmental, infralabial II, and four gular scales. Infralabials bordered by a single row of enlarged and elongated scales starting from centre of infralabial III to infralabial VI on right and from below infralabial III to infralabial VII on left. Eight supralabials (to midorbital position) on either side; 11 supralabials (to angle of jaw) on the right and 10 on the left; eight infralabials (to angle of jaw) on the either side.

Body slender, trunk not elongate ( TRL / SVL 0.46), with indistinct ventrolateral folds without denticulate scales. Dorsal pholidosis heterogeneous, composed of conical, granular scales intermixed with irregularly arranged, longitudinal rows of 12 or 13 slightly larger, rounded, keeled tubercles at midbody, extending from nape to tail; those on nape and two parasagittal rows more or less of similar size, smallest, gradually increasing in size laterally, being largest on flanks; roughly two to three times longer than adjacent granules, surrounded by a rosette of eight or nine small granules, 2–5 granules between two adjacent enlarged tubercles. Ventral scales much larger than granular scales on dorsum, roughly hexagonal, smooth, imbricate, more or less similar in size; midbody scale rows across belly 24 or 25; gular region with still smaller, smooth, rounded, subimbricate scales, increasing in size anterolaterally, those below mental, postmentals and infralabials are largest.

Femoral and precloacal pores absent. Scales on the palm and sole smooth, granular, rounded; scales on forelimb homogeneous, dorsal aspect with rounded, smooth, subimbricate scales which are slightly smaller than largest enlarged tubercles on dorsum, those on ventral portion are smaller and granular; scales on hindlimbs heterogeneous in size and shape, dorsal part of thigh and shank are similar to the dorsum, with granular scales, intermixed with scattered, enlarged, rounded, slightly conical, feebly keeled tubercles, which are denser on shank than thigh, anterior portion of thighs and ventral aspect of hindlimbs with much enlarged, smooth, imbricate scales. Fore and hind limbs relatively slender; forearm short ( FL / SVL 0.14); tibia short (CL/ SVL 0.15); digits moderately long, strongly clawed; 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 oblique series divided, except a distal and one or two basal scansors in all digits single; scansors from most proximal at least twice the diameter of palmar scales to most distal single scansor: 4-6-6-7-6 (left manus), 4-6-6-7-6 (right manus; Fig. 3 E ), 4-7-7-7-6 (left pes) 4-7-8-8-6 (right pes; Fig. 3 F ). The first digit on all limbs shorter, slightly less than half the length of second digit. Relative length of digits (measurements in mm in parentheses): III (2.9)> IV (2.8)> V (2.6)> II (2.4)> I (1.7) (left manus); IV(3.5)> V (3.2)> III(3.1)> II(3.0)> I(1.8) (left pes).

Tail slightly depressed, verticillate, oval in transverse section with indistinct median dorsal furrow; dorsal tail pholidosis heterogenous with smaller, rounded, smooth, subimbricate scales, gradually increasing in size laterally, intermixed with four to six enlarged, conical, weakly keeled tubercles on every whorl, two to three on either side of median dorsal furrow; scales on regenerated tail dorsum subimbricate; ventral scales enlarged, imbricate, median row (subcaudal plates) covering almost entire base of the tail except regenerated portion, bordered laterally by two or three rows of larger, smooth, imbricate scales; those close to vent small, smooth, flat and imbricate ( Fig. 2 B ). Postcloacal spurs indistinct.

Colouration in preservative ( Fig. 2 ). Dorsal ground colour of head, body, limbs and tail beige with scattered indistinct light brown blotches. Two distinct dark preorbital streaks, upper narrower and converging from each side and meeting at rostral, roughly ‘V’ shaped when viewed from above; lower bordering supralabials 3 to 6; distinct postorbital streak broader than the lower preorbital streak and extends from behind eye until above forelimb insertions. Head dorsum mottled, three large spots forming a transverse series on occiput; distinct dark nuchal collar extending across base of neck and fusing with postorbital streak on either side anterior to forelimb insertions; labials with fine black spots. Dorsum with four dark approximately X-shaped markings between limb insertions. The first lies just posterior to forelimb insertions and consists of a central longitudinally elongate rectangular spot, flanked on its four corners by four smaller or subequal spots. The other three sets of markings are less distinct but always include the central elongate spot, and may be similar to the first set of markings (third set) or consist of the central marking flanked by a single spot on either side (second and fourth set). Forelimbs and femur mottled with light and dark splotches, tibia and digits with dark crossbars; tail with seven dark cross bars on original portion, regenerated portion darker than rest of tail ground colour. Venter off-white, immaculate.

Colouration in life ( Fig. 5A ; based on paratype CES 16128). Dorsal ground colour of head, body, limbs and tail beige with light tinge of yellow and scattered indistinct light brown blotches. Two distinct dark preorbital streaks enclosing a yellow streak, upper narrower, starting as a dark spot, converging from each side and meeting at rostral, roughly ‘V’ shaped when viewed from top, lower terminating at supralabials third and fourth; distinct postorbital streak flanked by diffuse yellow markings which is broader than the lower preorbital streak and extends from behind eye until above forelimb insertions; anterior portion of brille yellow. Head dorsum mottled, snout suffused with yellow, rostral yellow; interorbital region slightly bluish; a large and small dark spot and pale blotch on occiput; distinct dark nuchal collar extending across base of neck and fusing with postorbital streak on either side anterior to forelimb insertions; labials with fine black spots, anterior more strongly spotted and suffused with yellow. Dorsum with scattered light blotches and an indistinct light mid-ventral line; four dark approximately X-shaped markings between limb insertions. The first lies just posterior to forelimb insertions and consists of a central longitudinally elongate rectangular spot, flanked on its four corners by four smaller or subequal spots. The other three sets of markings are less distinct but always include the central elongate spot, and may be similar to the first set of markings (third set) or consist of the central marking flanked by a single spot on either side (second and fourth set). Forelimbs and femur mottled with light and dark splotches, tibia and digits with dark crossbars; tail yellow with 11 dark cross bars those are distinct towards the base becoming pale and indistinct towards the tail tip. Venter off-white, immaculate.

Variation and additional information from type series ( Fig. 4 , Table 3). There are three male and six female specimens ranging in size from 31.0 – 41.8 mm (average 39.2 mm). The paratypes resemble the holotype except as follows: the number of lamellae on digit IV of manus is 7 except CES 17029 which has 6. The number of supralabials is 9–11 except CES 17031 has 8 on left side. The inner pair of postmental is in contact with each other except NRC-AA-1107 and CES 17031 not in contact. Femoral pores on either side are separated by two unpored scales but CES 17029 has single. The overall colour pattern is consistent across the type series, though the size and shape of dorsal markings are variable, the first mark on the back behind forelimb insertion is distinctly ‘X’ shaped and other two bands on back are distinct in NRC-AA-1107, CES 16129 and NRC-AA-1109. There are 13 dark bands on the complete original tail of 16128 and CES 16129 and 11 on NRC-AA-1109, but the regenerated tail lacks these markings. The nuchal collar in 16129 is indicated by only two spots and CES 17029 and CES 17031 by three spots .

Distribution. Hemidactylus flavicaudus sp. nov. is currently known only from Guddeguda, the type locality and Oblaipalle, ~ 7–8 km away, both in Mahabubnagar District, Telangana, India.

Habitat and Natural History. The type locality of Hemidactylus flavicaudus sp. nov. is a small rocky outcrop close to Guddeguda village characterised by large rocky boulders interspersed with scrub vegetation ( Fig. 9 ), as is the other known locality Oblaipalle. All individuals of the new species were found at night on vertical surfaces of boulders and usually at a relatively low height of 90–120 cm from the ground. The most common species of Hemidactylus on the boulders were H. cf. treutleri followed by H. flavicaudus sp. nov. Other sympatric rupicolous congeners included H. cf. giganteus Stoliczka and a large tuberculated undescribed species (denoted by “ Hemidactylus species 3” from Lajmi & Karanth 2020). The terrestrial Hemidactylus cf. gleadowi was also noted in the vicinity of the rocky outcrop, on the soil surface. CES16128 and CES16129 collected on 20 April were noted to be carrying eggs, indicating this to be the breeding period ( Fig. 5 A ).

Figures

FIGURE 2. Hemidactylus flavicaudus sp. nov. (holotype, NRC-AA-1105), dorsal view (A), ventral view (B). Scale bars 10 mm.

FIGURE 3. Hemidactylus flavicaudus sp. nov. (holotype, NRC-AA-1105), head in dorsal view (A), ventral view (B), lateral view (C), view of femoral region showing femoral pores (D), ventral view of right manus (E), and ventral view of right pes (F). Scale bars 5 mm.

FIGURE 4. The type series of Hemidactylus flavicaudus sp. nov.

FIGURE 5. The new species in life: top, Hemidactylus flavicaudus sp. nov. (paratype, NRC-AA-1107); bottom, Hemidactylus xericolus sp. nov. (holotype, NRC-AA-1110).

FIGURE 9. The type locality of Hemidactylus flavicaudus sp. nov., near Guddeguda, Mahabubnagar District, Telangana.