Bronchocela nicobarica, Chandramouli & Adhikari & Amarasinghe & Abinawanto, 2023

Chandramouli, S. R., Adhikari, Omkar D., Amarasinghe, A. A. Thasun & Abinawanto, A., 2023, A review of the genus Bronchocela Kaup, 1827 (Reptilia: Agamidae) in the Nicobar Archipelago with the description of two new species, Zootaxa 5254 (4), pp. 493-516 : 504-505

Bronchocela nicobarica sp. nov.

( Fig. 7 )

Bronchocela sp. 2 — Vijayakumar (2005)

Holotype: DOSMB 05070, an adult male, collected from Makachua, (7.40637ºN, 93.70894ºE, 23 m asl.), Little Nicobar, Nicobar Islands, India by S.R. Chandramouli in April 2017.

Paratypes: DOSMB 05055, an adult male, collected from Makachua , Little Nicobar Island ; DOSMB05056, an adult female collected from Pulo Ulon (7.29238ºN, 93.68415ºE, 36 m asl.), Little Nicobar Island in April 2017 (coll. as above) .

Etymology: The specific epithet is a toponym, in feminine gender, referring to the distribution ( Nicobar Islands) of the new species.

Differential diagnosis and comparisons: A species of Bronchocela endemic to the Southern group of Nicobar Islands, excluding Great Nicobar, characterized by small body size (68.32–79.04 mm SVL); relative tail length comparatively shorter (319 % SVL in B. nicobarica sp. nov. versus 331% in B. danieli ); 62–63 scalerows around mid-body (versus greater, 65–71 in B. danieli ), of which, the first three rows on the dorsum oriented posterodorsally, the next two rows oriented posteriorly (versus four in B. danieli ), followed by 10–11 rows oriented posteroventrally; 10–12 slightly enlarged, relatively short scales forming the nuchal crest; dorsal crest rudimentary; three postmentals; eight supralabials; 7–9 infralabials; four canthals; 7–9 supraciliaries; 30–33 subdigital lamellae (versus 25–27 in B. danieli ) under toe IV; 76–80 ventrals; pale green dorsal colouration with a black coloured ring around the eyes in males, but males lacking the characteristic dark patch behind the eye (versus always present in B. danieli ) ( Table 2 ).

Description of the holotype: An adult male, measuring 79.04 mm SVL; with a short, incomplete tail and a long and slender body (AG:SVL 0.45). Tail 134 mm, broken and incomplete. Head large (HL:SVL 0.27); longer than broad (HL:HW 1.67) and broader than deep (HW:HD 1.21). Snout long (ES:HL 0.43) with a blunt, rounded tip. Canthus rostralis sharply defined, with four canthal scales. Eyes fairly large, more than 1/4 th the length of the head (ED:HL 0.27); tympanum nearly triangular, relatively small, less than half as large as the eye (TYH:ED 0.46) and black in colour. Scales between the eye and tympanum slightly enlarged and keeled, in four rows. Nasal relatively large, with a pointed anterior and rounded posterior ends. Scales on the check below the tympanum elongated and feebly keeled. Mental triangular, bounded by three small postmentals; two larger ones on the sides with a small scale in between and seven infralabials on either sides. Rostrum with a small bulge above the rostral scale, bounded by eight supralabials on each side. Nostrils separated from each other by nine small internasals. Nuchal crest composed of twelve slightly enlarged, triangular scales projecting posterodorsally. Dorsal body scales relatively small, feebly keeled and homogeneous, in 62 rows around the mid-body. Of the dorsal scales, the first two rows on the dorsum on either sides oriented posteriorly; the next three rows of scales oriented posterodorsally, with the rest of the scales on the lateral body oriented posteroventrally. Ventrals 76 in a longitudinal series; much larger and broader than the dorsal scales, bearing a strong median keel, projecting posteriorly towards the lower vertex. Limbs relatively slender and elongate; upper arm long and slender (UAL:SVL 0.21); lower arm nearly as long as the upper arm (UAL:LAL 1.07); palm shorter than the lower arm (LAL:PAL 1.21). Fingers long and slender, relative length of fingers IV>III>V>II>I. Thigh long and slender (FEL:SVL 0.27); tibia nearly as long as the thighs (FEL:TBL 0.99); foot elongated, slightly longer than thigh (FEL:FOL 0.92). Hindlimbs much longer than half the body length (HLL: SVL 0.85). Relative lengths of toes IV>III>V>II>I; 30 subdigital lamellae under toe IV.

Dorsal coloration (in life) dull green throughout the body, head pale brown; tip of the tail brownish. Ventral side of the head and body of a lighter shade of green than the dorsum. Tympanum black, lacking a dark eye-patch. Upon preservation, much of the green body colouration decolorized to uniform grey on the head and body. Venter uniform pale white.

Variation: Measurements and scale-counts of the paratypes are presented in Table 3 . Female slightly smaller than males, uniform green dorsally, lacking nuchal crest.

Distribution and Natural history: Recorded only on Little Nicobar during the present study. However, it has been reported from other smaller islands in the southern Nicobar Islands such as Menchal, Kondul and Pilo Milo ( Vijayakumar, 2005). It is arboreal and diurnal in habit and is a fairly common species found in evergreen forests and plantations ( Fig. 8 ).

Figures

FIGURE 7. Bronchocela nicobarica sp. nov. (top: Holotype DOSMB 05070, middle: live male, below: live female).

FIGURE 8. Map, showing the distribution of the four Bronchocela species in the Nicobar Archipelago (red triangles indicate type localities).