Raorchestes emeraldi, Vijayakumar, S. P., Dinesh, K. P., Prabhu, Mrugank V. & Shanker, Kartik, 2014

Vijayakumar, S. P., Dinesh, K. P., Prabhu, Mrugank V. & Shanker, Kartik, 2014, Lineage delimitation and description of nine new species of bush frogs (Anura: Raorchestes, Rhacophoridae) from the Western Ghats Escarpment, Zootaxa 3893 (4), pp. 451-488 : 470-472

5. Raorchestes emeraldi sp. nov.

( Figures 2 , 3 & 8 ; Tables 2 & 3)

Holotype: ZSI/ WGRC /V/A/873 ( CESF 1353), an adult male (SVL 36.5 mm), collected by S.P. Vijayakumar and Saunak Pal in August 2011 from a site (10.3690 N, 76.9948 E) in a wet evergreen forest fragment, Valparai Plateau, Anaimalai Massif ( Fig 1 ), Peninsular India.

Paratype: ZSI/ WGRC /V/A/874 ( CESF 1365), an adult female (SVL 50.5 mm), collected by S.P. Vijayakumar and Saunak Pal in August 2011 from a site (10.3919 N, 76.9942 E) in a wet evergreen forest fragment, Valparai Plateau, Anaimalai Massif ( Fig 1 ), Peninsular India.

Lineage diagnosis. Raorchestes emeraldi sp. nov. can be diagnosed by its affinity to the Hassanensis clade ( Fig 3 ) and in having moderate levels (16S—3.5%) of divergence from its sister lineages R. ponmudi and R. hassanensis . Morphologically, it shows differences in the dorsum coloration (uniform green), groin patterns and iris coloration ( Fig 8 ). Of the known species of Raorchestes , this species was found to be of the largest (50.5 mm: female). Phylogenetic position and morphological distinctness are the two axes on which this lineage is diagnosed.

Field diagnosis. Morphology. Raorchestes emeraldi sp. nov. resembles its sister lineage R. ponmudi in overall morphometric characters, however it exhibits strong divergence in coloration from its sister lineages, R. hassanensis and R. ponmudi . It could be distinguished in having green dorsum ( Fig 8 a) (vs. dorsum with varying shades of brown in R. ponmudi (Biju and Bossuyt, 2009)) ; region of groin, front and back of thighs, under side of tibia and front of metatarsal with brown and yellow reticulated pattern (vs. posterior surface of thighs light chocolate brown vermiculated with grey patches of variable size in R. ponmudi ( Biju and Bossuyt, 2009) ; Additionally new species can be differentiated from other related congeners by the following combination of characters; (1) large adult size (SVL 36.5–50.5 mm, n=2); (2) head width larger than head length (HW 15.2–21.0 mm & HL 12.9–16.2 mm); (3) snout sub acuminate, sub equal to eye length (SL 5.0– 6.5 mm & EL 5.1–6.9 mm); (4) skin on dorsum lateral side smooth and ventral region granular; (5) dorsum green with minute yellow spots.

Geography. Restricted to the Anaimalai Massif (see natural history and distribution for details).

Description of holotype (all measurements in mm). A large sized bush frog (SVL = 36.5 mm), width of head broader than head length (HW = 15.2 mm; HL = 12.9 mm), flat dorsally; snout short and sub acuminate, slightly protruding beyond mouth. Snout length is sub equal to diameter of eye (SL = 5.0 mm, EL = 5.1 mm). Canthus rostralis angular rounded, loreal region slightly concave. Interorbital space (IUE = 4.0 mm) flat and equal to upper eyelid (UEW = 3.3 mm). Interorbital space between posterior margins of the eyes 1.9 times that of anterior margins (IFE = 7.0, IBE = 13.3 mm). Nostrils oval and nearer to the tip of the snout. Moderate symphysial knob. Pupil horizontal. Tympanum moderate, rounded, visible behind the eye, 2.3 times less than the eye diameter ( TYD = 2.2 mm). Tongue bifid, granular with a papilla. Supratympanic fold from behind eye to shoulder.

Relative length of fingers I<II<IV<III, finger tips with well developed disks (fd3 = 2.7 mm; fw3 = 1.4 mm) with distinct circum-marginal grooves, fingers with dermal fringes on both sides. Webbing on palm absent, subarticular tubercles moderate, rounded and pre-pollex indistinct. Supernumerary tubercles absent.

Hind limb long, heels touch when folded at right angles to the body. Thigh/Femur (TL = 17.0 mm), slightly lesser than Shank/Tibia (ShL = 18.2 mm) length and foot (FOL = 16.0 mm) and much less than heel to tip of fourth toe ( TFOL = 26.0 mm). Relative toe length I<II<III<V<IV, webbing medium, web formula (I 1- 1 II ½- 1 III ½- 1 IV 1- 0 V). Tibiotarsal articulation reaches posterior corner of eye. Outer metatarsal tubercle, supernumerary tubercles and tarsal tubercle absent.

Color in life. Dorsum uniform green with scattered yellow spots ( Fig 8 a); green colouration extending to canthus, arm up to ¼th of outer finger (rest of the fingers flesh coloured, finely speckled with brown), surface of femur, tibia, tarsus and base of outer two toes. Armpits are fleshy, purplish with fine brown specks. Upper lip golden white, lower lip and throat region iridescent off white. Lateral part of mid belly with yellow spots on a dark brown background. Groin, anterior and posterior femur with distinct yellow blotches on a dark brown background. Outer posterior orbital ring bluish green, upper edge of iris dark maroon, interior of iris golden brown with fine markings radiating towards the outer edge. Outer edges of the iris with a green wash ( Fig 8 b).

Etymology. The species is named after its dominant dorsum colour ‘emerald’.

Natural history and distribution. We discovered this species from a rainforest fragment at the eastern edge of the Valparai plateau. It appears to be a forest species, occurring in the higher elevation (1249–1488, n = 7) wet evergreen forests of the Anaimalai Massif ( Fig 1 & 2 ). It replaces R. ponmudi , a common species of the low and mid-elevations (mean ~ 900 m, n=77) of southern parts of the Western Ghats. We suspect a narrow zone of overlap between these species around 1200–1400 m in the Valparai plateau.

Figures

FIGURE 2. Geographic distribution of new species of bush frogs (Raorchestes) from Western Ghats. Orange filled circles

FIGURE 8. Raorchestes emeraldi sp. nov. (a) profile in life; (b) eye profile in life; (c) dorsal profile of holotype; (d) ventral profile in life.

FIGURE 3. A maximum likelihood tree for bush frogs, and in the Western Ghats, based on three MtDNA genes: 16 S, Cytb and ND 1. The lineages described are marked in red. Sub-clades are named on the right.

FIGURE 1. A map of the Western Ghats showing the major physiographic features referred to in the text.