Raorchestes blandus, 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 : 466-468

3. Raorchestes blandus sp. nov.

( Figures 2 , 3 & 6 ; Tables 2 & 3)

Holotype: ZSI/ WGRC /V/A/869 ( CESF 104), an adult male (SVL 18.4 mm), collected by S.P. Vijayakumar and Mayavan during August 2008, from a fragmented lowland wet evergreen forest site (10.1284 N, 76.7588 E) on the western side of the Anaimalai Massif ( Fig 1 ), Western Ghats, Peninsular India.

Paratype: ZSI/ WGRC /V/A/870 ( CESF 329), an adult male (SVL 19.1 mm), collected by S.P. Vijayakumar and Mayavan in June 2009 from an evergreen forest site (8.6667 N, 77.1833 E) in the Parambikulam protected area, western slopes of Anaimalai Massif ( Fig 1 ), Western Ghats, Peninsular India.

Lineage diagnosis. Raorchestes blandus sp. nov. can be readily discerned on a phylogenetic tree ( Fig 3 ), and is characterized by high genetic divergence (16S—14.1%) from its close relative R. chotta . Morphologically, it could be confused with R. chotta , but could be discerned using their morphological characteristics (See Field diagnosis). It is also very distinct on major aspects of morphology and coloration from Raorchestes archeos sp. nov ( Fig 4 , also see field diagnosis section of Raorchestes archeos sp. nov.).

Field diagnosis. Morphology. Raorchestes blandus sp. nov. could be superficially confused with Raorchestes chotta . However Raorchestes blandus sp. nov. can be distinguished from R. chotta in the larger male adult size of SVL 18.5 (18.0–19.5, n=4) (vs. 16.6 (16.0–17.2, n=7) in R. chotta ); shorter head length, HL/SVL=0.30 (0.28–0.32, n=4) (vs. HL/SVL=0.38 (0.36–0.41, n=7) in R. chotta ); Head width (HW=7.5, 7.2–7.7, n=4) longer than head length (HL=5.6, 5.1–6.0, n=4) (vs. head width (HW=6.5, 6.0–6.9, n=7) equal to head length (HL=6.4, 5.8–6.7, n=7) in R. chotta ); shorter snout length, SL/SVL=0.14 (0.13–0.15, n=4) (vs. SL/SVL=0.17 (0.16–0.18, n=7) in R. chotta ). Presence of rufous irregular glandular patches on the dorsal surface of skin in the shoulder, posterior side of the body, and in the joints of arms (vs. absence of glandular patches in R. chotta (Biju and Bossuyt 2009)) .

Ecology. Restricted to the under-storey in wet evergreen forests.

Geography. This species is restricted in distribution to the low and medium elevations of the western slopes of Anaimalai massif (see natural history and distribution for details).

Description of holotype (all measurements in mm). A small sized bush frog (SVL = 18.4 mm), width of head broader than head length (HW = 7.7 mm; HL = 5.1 mm), flat dorsally; snout acutely pointed in total profile, slightly protruding beyond mouth. Snout length is sub equal to diameter of eye (SL = 2.4 mm, EL = 2.7 mm). Canthus rostralis angular, loreal region flat. Interorbital space (IUE = 2.0 mm) flat and equal to upper eyelid (UEW = 2.0 mm). Interorbital space between posterior margins of the eyes 1.8 times that of anterior margins (IFE = 3.6, IBE = 6.4 mm). Nostrils oval, nearer to tip of snout. Weak symphysial knob. Pupil horizontal. Tympanum minute, rounded, barely visible behind the eye. Tongue bifid, granular with papilla. Supratympanic fold from behind eye to shoulder.

Relative length of fingers I<II<IV<III. Finger tips with well developed disks (fd3 = 0.8 mm; fw3 = 0.5) with distinct circum–marginal grooves, fingers with dermal fringes on both sides. Webbing on palm absent, subarticular tubercles moderate and pre-pollex tubercle oval, distinct. Supernumerary tubercles absent.

Hind limb long, heels touch when folded at right angles to the body. Thigh/Femur (TL = 8.8 mm), sub equal to Shank/Tibia (ShL = 8.6 mm); longer than foot (FOL = 6.8 mm) and less than heel to tip of fourth toe (TFOL = 11.4 mm). Relative toe length I<II<III<V<IV. Webbing weak, web formula, (I 1- 1 II 1- 2 III 1½- 2 IV 2- 1 V). Tibiotarsal articulation reaches anterior corner of eye. Outer metatarsal tubercle, supernumerary tubercles and tarsal tubercle absent.

Color in life. Dorsum rufous or brown with irregular dark brown blotches; small orange/rufous glandular patches on the head ( Fig 6 a), shoulder, elbow, on the dorsum, posterior part of back and on the finger; throat finely speckled with brown; fore and hind arm barred. Skin on dorsum finely granular.

Etymology. The species named after its pleasant (Latin: bland =pleasant) call notes. Common in the lowland wet forests of Anaimalai.

Natural history and distribution. A forest dwelling lineage, it is usually observed calling from understory shrubs. The distribution ranges from low to mid elevations (45–806 m, n=13) of Anaimalai Massif ( Fig 1 & 2 ). Current data suggests that there is no overlap in the geographical range of Raorchestes blandus sp. nov. with its close relatives R. chotta and Raorchestes archeos sp. nov. An additional population that resembles this lineage was encountered in the medium and low elevations of Periyar Plateau. Considering a potential zone of overlap with the northern range R. chotta , we reserve the identity of this population for further verification.

Figures

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

FIGURE 4. Raorchestes archeos sp. nov. (a) profile in life; (b) eye profile in life; (c) dorsal profile of holotype; (d) ventral profile in life.

FIGURE 6. Raorchestes blandus sp. nov. (a) profile in life; (b) eye profile in life; (c) dorsal profile of holotype; (d) ventral profile of holotype.

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.