Sitana attenboroughii Sadasivan & Ramesh & Palot & Ambekar & Mirza 2018, sp. nov

Autor: Sadasivan, Kalesh, Ramesh, M. B., Palot, Muhamed Jafer, Ambekar, Mayuresh, Mirza, Zeeshan A.
Rok vydání: 2018
Předmět:
DOI: 10.5281/zenodo.5696044
Popis: Sitana attenboroughii sp. nov. Figs. 1���6, Table 1 Holotype.��� Adult male, BNHS 2481, Trivandrum, Kerala, India (8.313387��, 77.070933��, elevation 9 m), collected by Muhamed Jafer Palot, 15.06.16. Paratypes (n=2).��� Adult male, BNHS 2482 collected by Muhamed Jafer Palot, Kalesh Sadasivan and Ramesh M. B, on 15.06.16.; adult female, BNHS 2483, from the same locality and collectors 15.06.16. Diagnosis. A moderately large sized species in relation to other members of the genus, SVL 55.6 mm. Dewlap colouration in breeding male iridescent blue and bright orange. Enlarged scales on dewlap moderately serrated. Dewlap moderately large, extending up to 36% of the trunk. More than 72���74 ventral scales and 35���38 vertebral scales. Sitana attenboroughii sp. nov. differs from members of the genus Sarada by having an enlarged spine-like scale on the thigh and maximum SVL of 55.7 mm (vs. SVL> 60 mm and an enlarged spine-like scale absent on the thigh in Sarada deccanensis, Sarada darwini and Sarada superba); differs from members of the genus Sitana in the dewlap coloration being vibrant orange and blue (vs. dewlap coloration yellowish white and may bear a faint blue line in S. sivalensis complex, S. laticeps and S. spinaecephalus); dewlap extending to over 36% of the trunk length (vs. 56% in S. visiri, 33% in S. devakai, 29% in S. bahiri, 46% in S. ponticeriana, 64% in S. marudhamneydhal); SVL 45.7���55.8 (vs. SVL 42���54 in S. marudhamneydhal, 36.36���44.5 in S. ponticeriana, 41.7��� 48.5 in S. laticeps); DWL 25.8���33.3 (vs. 37.3���40.5 in S. marudhamneydhal, 22.4���29.2 in S. ponticeriana, 24.5���39 in S. visiri, 26.1���32.6 in S. spinaecephalus, 20.7���27.1 in S. laticeps); ventral scales 72 or 73 (86���89 S. bahiri, 100��� 108 in S. devakai, 75���81 in S. laticeps , 80���84 in S. marudhamneydhal). The new species is most similar to S. visiri in general appearance from which it differs in possessing higher ventral counts 72���74 (vs. 65���69 in S. visiri). Other characters which may be used to distinguish the new species are presented in the key to the genus and an overview of selected characters are presented in Table 2. Description of holotype male BNHS 2481: The holotype is in generally good condition, lacking any incisions or cuts. The tail is complete and fixed in a ���U��� shaped curl against the body. Hemipenis not everted (Fig, 1A & 1B). Adult male SVL 55.8. Head relatively long (HL/SVL ratio 0.26), wide (HW/HL ratio 0.67), not depressed (HH/HL ratio 0.52), distinct from neck (Fig. 2). Snout moderately long (SE/HL ratio 0.43) bluntly conical; longer than eye diameter (OD/SE ratio 0.44) (Fig. 3). Eye large (OD/HL ratio 0.19); pupil round, eyelids covered with small pentagonal and hexagonal scales, supraciliaries short. Snout obtusely pointed when viewed dorsally, rostral much wider than deep, bordered posteriorly by two supralabials, prenasal and dorsally by three small scales. Canthus rostralis and supraciliary edge moderately sharp consisting of nine scales. Nostrils positioned in the centre of a large, undivided nasal plate, bordered by seven scales(right side), including one prenasal, two postnasals and one supranasal, and separated from rostral by prenasal and supralabials. Nine rectangular, weakly keeled supralabials, bordered above by a single row of slightly smaller, rectangular, keeled scales, terminating above eighth the supralabial. Loreal region concave, scales of the loreal region heterogeneous in size, flat, keeled, some roughly hexagonal. Scales on postorbital and temporal region homogenous, imbricate, strongly keeled, and directed posteriorly and dorsally. Orbital scales small but not granular. Tympanum naked. Canthals enlarged, overlapping, becoming slightly smaller along subimbricate supraciliaries, protruding slightly laterally on supraorbital ridge. Scales on dorsal surface of snout, forehead, interorbital, and occipital region heterogeneous in size, and shape; mostly elongate, imbricate, strongly keeled longitudinally; those on snout smaller, rhomboidal, those on forehead largest, greatly elongate; supraorbital scales increase in size becoming more elongate from supraciliaries to inner edges of orbits, of which the enlarged scales follow the curvature of the orbit posterolaterally; occipital region with slightly smaller, less elongate; imbricate, and keeled scales. Parietal plate with pineal eye, the plate slightly larger than adjacent scales. Mental shield narrower than rostral; gular scales keeled. Dewlap moderately large, extends posteriorly over 36% of trunk length, with posterior scales extending slightly beyond axila, not extending to midventer, approximately four to five rows of anteriodorsal dewlap scales (blue in colour) smaller, elongate, pointed, keeled, remainder of scales much larger, keeled, lanceolate, bluntly pointed, gradually increasing in size towards margin, single marginal row largest with many more pointed scales. 16 enlarged rows of scales on dewlap. Nuchal and dorsal crest weak. Scales on nuchal region smaller, less than half the size of those on interorbital region, imbricate, strongly keeled. Body slender, 51 rows of scales around midbody, of these 10 to 12 rows of scales on back, from occiput to pectoral region homogenous in size, shape, slightly larger than those on neck, imbricate, pointed, keeled, and directed posteriroly forming regularly arranged longitudinal rows; those on flanks heterogeneous in size, shape, smaller than those on back, obtusely pointed, keeled, with irregularly scattered, slightly larger, pointed, keeled scales; scales of upper rows directed backwards and upwards; ventral rows backwards and downwards; ventral scales subimbricate, keeled, homogenous in size, shape, arranged in 72 rows; no precloacal or femoral pores. Fore and hind limbs relatively slender, tibia short (CL/SVL ratio 0.29); digits moderately long, ending in strong, elongate, slightly recurved claw; inter-digital webbing absent; subdigital lamellae entire, tri-mucronate, 25 subdigital lamellae on toe IV; relative length of fingers 4>3>2>5>1, toes 4>3>2>1. Fore and hind limbs covered above and below with regularly arranged, enlarged, pointed, strongly keeled, scales. Enlarged projecting scale on thigh absent (Fig. 4). Tail entire; tail base swollen; tail uniformly covered with similar sized, keeled, weakly pointed, regularly arranged, posteriorly directed imbricate scales, no enlarged subcaudal row. Coloration in life (Fig. 5): Dark-brown above with five dark rhomboidal marks on the trunk, first mark present just posterior to the neck and the last one on the flank. Two lateral pale stripes running from posterior margin of the tympanum along the trunk above the flank. Limbs brown, banded with dark bands. Head coloration same as the body, except for the labials which are white with a tinge of yellow. Dewlap yellowish white at base, gradually turning into iridescent blue in its anterior one fourth region which in turn is replaced by bright-reddish orange, which covers the rest of the dewlap. A dark blue stripe runs along the line of attachment of the dewlap from the chin to insertion of the forelimb. The dewlap scale row attached to the trunk is white with a few scales with traces of the reddish orange color. Ventrally white. Coloration in preservative (Fig. 1���3): Coloration much more faded, overall background coloration more yellowish. Rhomboidal marks turn much paler and almost diffused on towards the flank. Bands on legs almost vestigial. Blue coloration on the dewlap turns black, from the mental to the anterior half of the dewlap. A few black spots on around the dewlap on the lower jaw. The dark blue stripe runs along the line of attachment of the dewlap from the chin to insertion of the forelimb more prominent in the preserved specimen which appears black. Etymology. The specific epithet is a noun honoring the celebrated naturalist and broadcaster Sir David Frederick Attenborough for his contribution towards natural history documentation and wildlife conservation. Variation. The paratypes resemble the holotype in most aspects with the holotype except for ventral belly scale number. The paratype male possesses 26 scales. Other morphometric and meristic characters are presented in Table 1. Natural history and distribution. The species occurs on coastal sand dunes of Poovar in Trivandrum district, Kerala (Fig. 11). The locality receive 1835���1865 mm of rainfall annually. The vegetation at Poovar is dominated by spiny grasses (Spinifex littoreus), sprawling runners of Ipomoea pes-caprae and Agave spp. (Fig. 12). The locality is close to the Poovar estuary, where Neyyar River meets Arabian Sea. Adult males were seen basking and displaying on the Agave fronds in the month of October. The male paratype was collected in the month of June and is an adult individual. Survey conducted at the type locality in the month of July yielded only hatchlings and no adults hinting that this species likely breeds twice in a year. The females were seen running on the sand among the spiny tangles of this coastal vegetation. Many burrows and foot prints of the species were also observed from the area. When disturbed, lizards sought shelter among the spiny bases of plants or within burrows. Males were active especially in the early mornings until noon when they were seen actively displaying their dewlap to other individuals. The area is under threat of human interference in form of construction activities, extraction of sand, beach litter, and fire. This is the only beach in southern Trivandrum where the sand dune and the lush growth of spiny grasses were noted during the survey and may be the only microhabitat in which Sitania attenboroughi resides. The type locality is under threat from tourism and fires. Immediate efforts must be made to ensure protection to the type locality. Suggested common name. Attenborough���s fan-throated lizard.
Published as part of Sadasivan, Kalesh, Ramesh, M. B., Palot, Muhamed Jafer, Ambekar, Mayuresh & Mirza, Zeeshan A., 2018, A new species of fan-throated lizard of the genus Sitana Cuvier, 1829 from coastal Kerala, southern India, pp. 545-564 in Zootaxa 4374 (4) on pages 547-552, DOI: 10.11646/zootaxa.4374.4.5, http://zenodo.org/record/1157006
Databáze: OpenAIRE
Externí odkaz: