Sitana marudhamneydhal, Deepak, V., Khandekar, Akshay, Varma, Sandeep & Chaitanya, R., 2016

Deepak, V., Khandekar, Akshay, Varma, Sandeep & Chaitanya, R., 2016, Description of a new species of Sitana Cuvier, 1829 from southern India, Zootaxa 4139 (2), pp. 167-182 : 171-178

Sitana marudhamneydhal sp. nov.

Fig. 6 , Fig.7 ; Table 3

Holotype. NCBS AQ 460, an adult male ( Fig. 6 ) from Kallidaikurichi, Tirunelveli District, Tamil Nadu, India (8°39’54” N; 77°27’15” E), 68 m elevation, collected on 12 November 2014 by V. Deepak and R. Chaitanya.

Paratypes CES 141124, an adult male from Kallidaikurichi, Tirunelveli District, Tamil Nadu, India (8°39’54” N; 77°27’15” E), 68 m elevation, collected on 12 November 2014 by V. Deepak and R. Chaitanya. BNHS 2313 an adult female from Kanyakumari, Kanyakumari District, Tamil Nadu, India (8°4’45” N 77°31’55” E), 68 m elevation, collected on 10 January 2014 by V. Deepak

Diagnosis. A large-sized Sitana with a maximum SVL of 55 mm, distinguished from all congeners by the following combination of characters: 1) dewlap extending beyond forearm insertion (vs not extending in S.

sivalensis complex including S. kalesari ); 2) highly serrated dewlap (vs faintly serrated in S. spinaecephalus and S. laticeps ); 3) large dewlap extending over up to 64% of trunk vs S. ponticeriana (46%), S. bahiri (29%), S. devakai (33%) and S. visiri (56%), 4. Large body size (average SVL) 51 mm vs S. bahiri (Rameshwaram population 42.1 mm; Sri Lankan population 34 mm), S. devakai 35 mm, S. visiri 50 mm and S. ponticeriana 40.5 mm, 5. Fewer dorsal scales (39–40) vs S. visiri (41–50).

Description of holotype. The holotype is in good condition, hemipenis partially everted, exposed and seen on both sides when viewed dorsally. Tail entire, curved towards right side. An adult male, SVL 55 mm. Head relatively long (HL/SVL ratio 0.27), wide (HW/HL ratio 0.63), not depressed (HH/HL ratio 0.56), distinct from neck. Snout short (SE/HL ratio 0.38), longer than eye diameter (OD/SE ratio 0.77), obtusely pointed in profile when viewed dorsally; rostral much wider than high, contacted laterally on either side by first supralabial and a large prenasal, dorsally by three smaller scales. Canthus rostralis and supraciliary edge sharp. Nostril elliptical, laterally positioned and placed in the centre of a large, undivided, pentagonal nasal plate. Nasal plate bordered by six scales on each side, two postnasals, one supranasal, one prenasal (separating it from rostral), first supralabial and one more enlarged scale, separating the nasal from the second supralabial. Seven supralabials on the right side (eight on left side), first twice as large as others, broader than long, roughly rectangular, strongly keeled, bordered above by a row of slightly smaller, rectangular, keeled scales, which start at posterior margin of first supralabial and terminate above the seventh. Loreal region concave, with scales of heterogeneous shape and size. Canthals enlarged, overlapping, keeled, slightly protruding on supraorbital ridge laterally. Eye large (ED/HL ratio 0.20); pupil rounded, eyelids covered with scales that are heterogeneous in shape and size, larger ones on the upper eyelid keeled; supraciliaries longer than broad. Orbital scales small but not granular. Scales on postorbital and temporal region homogenous, imbricate, strongly keeled, and directed backward and upwards. Tympanum naked. Canthal scales 4 on both sides. Orbit bordered below by a row of nine roughly rectangular, elongate, weekly keeled scales starting from posterior margin of nasal scale and terminating after the posterior margin of the orbit. Scales on dorsal surface of snout, forehead, interorbital and occipital region heterogeneous in size, shape, mostly elongate, imbricate, strongly keeled longitudinally; those on snout smaller, rhomboidal, those on forehead large, much elongate; supraorbital scales along the supraciliary edge elongate, keeled, decreasing in size posteriorly, following curvature of orbit; occipital region with slightly smaller, less elongate, imbricate and keeled scales. Parietals larger than surrounding scales, longer than broad, strongly keeled, completely divided by two smaller inter-parietal scales; anterior inter-parietal bicarinate, posterior elliptical, keeled, without visible pineal eye. Mental shield narrower than rostral, roughly pentagonal, pointed posteriorly; scales on the gular region keeled. Dewlap large (DEWL/TrL ratio 0.61), extends posteriorly over 60% of trunk, with posterior scales extending much beyond axilla, about seven to eight rows of anterior dewlap scales (colour is bluish in life & blackish in the specimen) smaller, elongate, pointed, keeled, remainder of scales much enlarged, keeled, lanceolate, bluntly pointed, gradually increasing in size towards margin; single marginal row largest with sharply pointed scales. Enlarged scales on dewlap in 21 rows. Nuchal and dorsal crest absent. Scales on nuchal region smaller, less than half the size of those on interorbital region, imbricate, strongly keeled. Body slender, 55 rows of scales around midbody; 10 to 12 dorsal rows including the vertebral scale row, starting from back of neck until groin, homogenous in size, shape, slightly larger than those on neck, imbricate, pointed, keeled, directed backwards forming regularly arranged longitudinal rows; those on flanks heterogeneous in size, shape, smaller than those on back, pointed, keeled, irregularly scattered with larger, pointed, keeled scales; scales of upper rows on flanks directed backwards and upwards, lower rows backwards and downwards; ventral scales subimbricate, keeled, homogenous in size and shape, arranged in 80 rows; no precloacal or femoral pores. Fore and hindlimbs relatively slender, tibia short (CL/ SVL ratio 0.33); digits moderately long, ending in strong, elongate, slightly recurved claw; inter-digital webbing absent; subdigital lamellae entire, tri-mucronate, 23 subdigital lamellae on toe IV; relative length of fingers 3> 4> 2> 5> 1, toes 4> 3> 2> 1. Fore and hindlimbs covered above and below with regularly arranged, enlarged, pointed, strongly keeled, scales. Tail long (TL/SVL ratio 2.7), entire, base swollen, uniformly covered with similar sized, keeled, pointed, regularly arranged, backwardly directed imbricate scales; subcaudal scales keeled, rounded near base, becoming pointed posteriorly; no enlarged subcaudal row.

Colour of holotype in life: Dorsum light to dark brown with a black patch on the neck, three brown rhomboidal markings on the trunk, relatively lighter than the one on the neck. A black ‘V’ shaped marking between the eyes. Limbs and tail with dark brown or black bands of variable width. A cream-coloured streak begins behind the nostril, extending below the eye and into flank region. Belly pale white (iridescent) in colour. Both forelimbs, hindlimbs, and tail have dark brown bars of variable width. Dewlap with dark blue colouration from the mental extending up to the anterior half margin of the dewlap, bright orange patches or spots present on the plain iridescent white dewlap; bright yellow patch on either side of dewlap starting approximately in the middle of lower jaw.

Colour of holotype in preservative: A dark roughly ‘V’ shaped band across the interorbital region of head. Dorsum dark brown with two much darker blotches on either side of neck. Vertebral scale row much lighter than dorsolateral scales. Flank much darker with light brown markings mostly on enlarged scales. Dark brown bars on limbs and tail, faintly visible. The dewlap colouration is faint.

Variation. The paratypes agree with the holotype in overall scalation except MBS (CES 141124 has 55 scale rows vs 52), VS (BNHS 2313 has 39 scales vs 40) and LAM4 (BNHS 2313 has 22 lamellae vs 23). Morphometric data for the paratypes are summarized in Table 3 . Morphological characters of females mostly agree with males except for the absence of a dewlap, lack of a swollen tail base, and a narrower head. In the type series, the nasal scale always touches the first supralabial. However, this character is not seen in other referred specimens (Appendix 1), where the nasal scale is separated from the first supralabial by the first scale in a row of enlarged scales above the supralabials.

Etymology. The species is named for its occurrence in the grassy plains as well as the seashore in Tamil Nadu, India. The specific epithet is derived from a combination of two ancient Tamil words (Tamil: Marudham = cultivable grasslands, Neydhal = land by the seashore).

Hemipenial morphology. One specimen from Kallidaikurichi (CES 141196) was examined. The hemipenis is bilobed, divided almost half its length ( Fig.8 A), relatively small, as wide as long, and shallowly forked. Base naked. Sulcus spermaticus single ( Fig. 8 B). Lips smooth. Calyces present on each lobe. Proximal half of sulcal and asulcal side with small deep polygonal calyces and apex unornamented. Ornamentation includes a combination of flounces and calyces. Papillae are present between the apical lobes. Ridges between the calyces are thin and show scalloped micro-ornamentation. Eight flounces present on the asulcal side ( Fig. 8 A) and 10–11 flounces are present on the sulcal side ( Fig. 8 B).

Natural history. The new species Sitana marudhamneydhal sp.nov. is found in coastal sand dunes, grassland habitats, open areas dominated with Prosopis juliflora and plains in the southern Tamil Nadu ( Fig. 9 ). It is so far recorded only south of the Thamirabarani river in Tamil Nadu. Other diurnal lizard species found in these habitats include Eutropis carinata , Eutropis bibronii , and Calotes versicolor . Breeding males were observed during the month of September and October. Hatchlings were recorded during the month of January.

Figures

FIGURE 6. Holotype of Sitana marudhamneydhal sp. nov. (NCBS AQ 460) from Kallidaikurichi, Tamil Nadu. (A) full body dorsal (B) flank region (C) dorsal view of head (D) lateral view of head. Scale bar: 10 mm.

FIGURE 7. Sitana marudhamneydhal sp. nov. A. An adult male from the type locality Kallidaikurichi. B. An adult female from the type locality (Uncollected specimens).

FIGURE 8. Hemipenis of Sitana marudhamneydhal sp. nov. CES 141196, 53.8 mm SVL. (A) asulcal view; (B) sulcal view. Scale bar: 2 mm.

FIGURE 9. Habitat of Sitana marudhamneydhal sp. nov. A. type locality Mayiladumparai in Kallidaikurichi, B. Sunset Point, near Kanyakumari.

Tables

TABLE 3. Measurements and morphological characters of the type series of Sitana marudhamneydhal sp. nov.

	NCBS AQ460(Holotype)	CES 141124	BNHS 2313
Sex	Male	Male	Female
HL	15.29	14.56	11.95
HW	9.77	9.57	7.64
HH	7.84	7.78	5.66
ET	3.86	3.78	2.83
IO	5.90	5.66	4.24
JL	12.58	12.47	9.62
NE	3.30	3.35	2.49
SE	5.93	5.64	4.44
SW	2.68	2.62	2.00
DEW	40.45	37.34	-
DEWL	13.16	11.54	-
TD	1.72	1.97	1.34
ED	4.40	4.37	3.34
F4	5.11	4.66	3.83
T4	11.46	11.67	8.24
FL	14.94	13.97	10.86
CL	18.36	17.18	13.31
HEL	22.27	21.84	17.37
LAL	9.28	8.79	7.09
UAL	9.17	9.19	6.73
SVL	54.98	54.59	42.39
TL	149.3	147.22	92.89
TW	4.97	4.97	3.57
TH	5.06	4.83	2.58
TrL	21.34	21.72	20.49
MBS	55	52	55
VEN	80	84	61
VENB	27	27	-
VS	40	40	39
LAM4	23	23	22
ESD	21	21	-