Raorchestes kakachi, Seshadri, Kadaba Shamanna, Gururaja, Kotambylu Vasudeva & Aravind, Neelavara Anantharam, 2012

Seshadri, Kadaba Shamanna, Gururaja, Kotambylu Vasudeva & Aravind, Neelavara Anantharam, 2012, A new species of Raorchestes (Amphibia: Anura: Rhacophoridae) from mid-elevation evergreen forests of the southern Western Ghats, India, Zootaxa 3410, pp. 19-34 : 21-30

Raorchestes kakachi sp. nov.

( Figures 2.a –b & 3.a–h; Table 1)

Suggested common name: Kakachi shrub frog

Holotype. ZSI/ WGRC /V/A/857, an adult male collected by KSS and TA on shrubs at 2 m height from Kakachi , near a stream on 23rd May 2011 during 19:40 hrs (8.549167° N latitude and 77.385833° E longitude, 1285 m amsl).

Paratypes. ZSI/ WGRC /V/A/858–859, consists of two males and three females collected in Kakachi . One male was collected by KSS in Kakachi , collection date same as holotype. The other male and a female were collected on 24th May 2011 at 20:51 hrs by KSS & PS (8.530833° N latitude and 77.359722° E longitude, 1300 m amsl). Two females were collected on 24th January 2011 at 20:30 hrs by KSS, NAA, TG and RG on riparian vegetation along a stream.

Diagnosis. Small sized adult Raorchestes (male: 24.7–25.8 mm, n = 3 and female: 24.3–34.1 mm, n = 3) diagnosed with the following characters. Absence of vomerine teeth; translucent vocal sac while vocalizing; active during night (observed between 18:00–23:00 hrs); all digits well differentiated with discs having distinct circummarginal grooves; absence of dermal folds and spur in forelimbs and hindlimbs. It is distinguished by all other congeners by the following combination of characters: (i) flat head; (ii) snout oval in dorsal view; (iii) tympanum indistinct; (iv) supra-tympanic fold distinct; (v) head wider than long; (vi) skin granular on throat, chest, belly, flanks, vent and lower parts of thigh; (vii) tuberculate projections on dorsum, upper eye lids, snout, tympanic region, fore limbs and hind limbs; (viii) colour on dorsum varying from ivory to brown, blotches of dark brown on flanks, brown mottling on throat reducing towards vent; (ix) fingers and toes with well developed discs, circummarginal groves folding upwards giving a bifid appearance in dorsal view; (x) intercalary ossification distinct, present between penultimate and distal phalanges of both fingers and toes as a white glandular projection; (xi) moderate webbing in hind limbs; (xii) distinct dark brown horizontal band on inner and outer surface of thigh, inner surface of shank and inner surface of tarsus extending up to first three toes on upper surface; and (xiii) iris colour brown.

Description of holotype (all measurements in mm, Figure 3. a –h): A small sized frog (SVL = 25.8), head wider than long (HW = 9.4; HL = 8.7), snout oval in dorsal view and in profile rounded. Eye length sub-equal to snout length (EL = 3.8; SL = 4.0). Canthus rostralis rounded, loreal region slightly concave. Interorbital space flat, almost equal to upper eyelid width and internarial distance (IUE = 2.6; UEW = 2.7; IN = 2.6). Internarial distance between posterior margins of eyes 1.8 times that of anterior margins (IFE = 5.2; IBE = 9.2). Nostrils oval, without flap, closer to tip of snout than to eye (NS = 1.7; EN = 2.5). Weak symphysial knob. Pineal ocellus absent. Tympanum indistinct, oval, closer to eye ( TYD = 1.1; TYE = 0.6), 3.5 times in eye length. Supratympanic fold distinct from back of eye to shoulder. Median sub-gular vocal sac with a pair of openings at the base of lower jaw. Tongue bifid (TLW, length = 5.4; width = 3.9), chordate, sparsely granular. Lingual papilla absent. Eyes moderately large (EL = 3.8), protruding, pupil horizontal.

Fore limb length shorter than hand length (FLL = 6.6; HAL = 7.2). Relative lengths of fingers I<II<IV<III (FL I = 1.3; FL II = 2.7; FL III = 3.9; FL IV = 2.8). Finger tips with well developed discs (FD I = 0.4, FD II = 0.5, FD III = 0.7, FD IV = 0.7; FW I = 0.8, FW II = 1.0, FW III = 1.5, FW IV = 1.5) with circum marginal grooves, grooves fold upwards, giving bifid appearance in dorsal view, intercalary ossification distinct between penultimate and distal phalanges ( Figure 3 . g). Dermal fringes weak, on both sides of the fingers. Webbing between fingers absent. Subarticular tubercles distinct (finger: i = 1, ii = 1, iii = 2, iv = 1) rounded and pre–pollex tubercle oval, distinct. Supernumerary tubercles present. Nuptial pad absent.

Hind limbs long, touch when folded at right angles to body. Shank 5.2 times longer than wide (ShL = 13.1; TW = 2.5), longer than thigh length (TL = 12.2) and longer than foot length (FOL = 9.3). Heel to tip of fourth toe (TFOL = 16.3) 7.8 times longer than fourth toe length (ToL = 2.1). Relative toe length I<II<III≤V<IV (ToL I = 1.7; ToL II = 2.2, ToL III = 3.1; ToL IV = 5.1; ToL V = 3.6). Toes with well develop discs at tip (TD I = 0.4, TD II = 0.5, TD III = 0.5, TD IV = 0.7, TD V = 0.7; ToW I = 0.9, ToW II = 0.9, ToW III = 0.9, ToW IV = 0.9, ToW V = 1.0). Webbing moderate (MTTF = 5.0, MTFF = 5.8, TFTF = 4.5, FFTF = 4.2). First toe (ToLI = 1.7) 1.9 times the length of inner metatarsal tubercle (IMT = 0.9 mm). Outer metatarsal tubercle absent, supernumerary tubercles and tarsal tubercle present (toe: i = 1, ii = 1, iii = 2, iv = 3, v = 2).

Skin: Snout, between eyes, sides of head, fore limb, hind limb and dorsum shagreened. Tuberculate projections on dorsum, upper eye lids, snout, fore limbs and hind limbs. Tympanic region sparsely granular. Venter granular, larger granulation on belly reducing towards throat, flanks and thigh. Lower part of flanks granular. Upper flanks sparely granular. Dorso-lateral folds and macroglands absent.

Colour in life. Male–dorsum pale-yellow brown with small dark irregular lavender spots. Head with a grey band between eyes. Sides of head cream coloured. Dark brown lower margin of supratympanic fold. Vocal sac translucent with granular grey spots. Iris reddish brown, pale blue semi-circular skin fold at the posterior corner of eyes, translucent nictitating membrane, margins speckled with brown. Upper and lower lip cream coloured. Forelimbs cream coloured, shoulder flesh coloured. Venter uniform flesh coloured from chest to vent, throat pale buff, mottled with brown. Flanks straw yellow, interspersed with brown blotches, groin brown. Distinct dark brown horizontal band on inner and outer surface of thigh, inner surface of shank and inner surface of tarsus extending up to first three toes on upper surface. Forelimbs and hind limbs with faint cross bands. Webbing in feet brown.

Colour in preservative. Male–dorsum and head brown. Lateral parts of body light brown. Head with a flesh coloured band between eyes. Forelimb and hand cream coloured with faint cross bands. Irregular black spots throughout dorsum. Flanks dark brown, interspersed with cream blotches which reduce towards groin. Groin brown. Distinct dark brown horizontal band on inner and outer surface of thigh, inner surface of shank and inner surface of tarsus extended up to first three toes on upper surface. Forelimbs and hind limbs with faint cross bands. Webbing in feet brown. Faint cross bands across thigh, shank and tarsus. Venter cream coloured, with brown speckles through out. Throat mottled with brown. Palm and feet with brown speckles ( Figure 3. a–f ).

Female–head with tetragonal cap, ivory coloured. Lateral parts of body buff with black-brown blotches. Upper half of flanks mottled with brown and cream patches. Distinct dark brown horizontal band on inner and outer surface of thigh, inner surface of shank and inner surface of tarsus extended up to first three toes on upper surface. Venter cream coloured. Throat mottled with brown. Distinct brown cross bands across fore limbs and hind limbs.

Etymology. Named after the locality of holotype – Kakachi . Kakachi is treated as an invariable noun in apposition to the generic name.

Sexual dimorphism. Male–nuptial pad absent; possess a median subgular vocal sac with a pair of openings at the base of the lower jaw; iris colour dark brown. Female–larger than the male (SVL: male–24.9 ± 0.8 mm, n = 3 and female–29.0 ± 4.9 mm, n = 3); ovary large, with creamy white eggs; head with a tetragonal cap like patch, pale pink to grey, iris colour reddish to golden brown. Distinct from that of male, in having dorsum dark grey, interspersed with straw yellow and black marbling throughout. Head with a distinct pale grey tetragonal patch. Sides of head cream-ivory with three dark brown stripes below the eyes till upper lip. Lower margin of supratympanic fold dark brown ( Figure 2 .b).

Variation ( Figure 4. a–c ): Details of the morphometric variations observed in 6 individuals is provided in Table 1. Morphologically, the dorsum colouration among males varied from dark brown to buff. One male individual (ZSI/WGRC/V/A 858, Figure 4. c ) was with coffee brown dorsum, ivory patches on lower part of tympanic region, loreal region, shoulder, knee and heel. Ivory spots on upper part of flank, lower dorsum, dorsal part of hand and foot. Variations also included distinct cross bands on both forelimbs and hind limbs, straw yellow colouration on the lower dorsum and overall dark reddish colouration on anterior dorsum. In females, the patch on head was uniform. Among immature females, the dorsum colour varied from pale brown to dark brown similar to that of males.

Comparisons. Raorchestes kakachi sp. nov. can be confused with R. flaviventris (Boulenger) and R. kaikatti (Biju & Bossuyt) by its overall morphology. However, R. flaviventris differs from R. kakachi sp. nov. in the following characters: tongue with lingual papilla vs. absent, tympanum distinct vs. indistinct, thigh length equal to shank length (ThL = 13.5 mm, ShL = 13.5 mm) vs. thigh length shorter than shank length (male, ThL = 12.1 ± 0.2 mm, ShL = 13.1 ± 0.4 mm, n = 3; female, ThL = 14.4 ± 2.2 mm, ShL = 15.1 ± 2.1mm, n = 3), webbing between fingers rudimentary vs. absent, dermal fringe on fingers absent vs. present, ventral side grey and dark-brown vermiculated throughout vs. ventral side grey with brown mottling reducing towards vent, forelimbs, tibia and foot, dorsal and posterior part of thigh brown with cream dots vs. distinct dark brown horizontal band on inner and outer surface of thigh, inner surface of shank and inner surface of tarsus extended up to first three toes on upper surface. R. kaikatti differs from R. kakachi sp. nov. in the following characters: head length equal to head width (male, HW = 9.6 ± 0.4, HL = 9.5 ± 0.4 mm) vs. head wider than long (male, HW = 9.4 ± 0.4, HL = 8.1 ± 0.5 mm; female, HW = 11.16 ± 2, HL = 9.3 ± 1.5 mm), thigh length equal to shank length (male, ThL = 12.5 ± 0.9 mm, ShL = 12.3 ± 0.8 mm, n = 5) vs. thigh length shorter than shank length (male, ThL = 12.1 ± 0.2 mm, ShL = 13.1 ± 0.4 mm, n = 3; female, ThL = 14.4 ± 2.2 mm, ShL = 15.1 ± 2.1 mm, n = 3), ventral side greyish white vs. brown mottling, posterior part of thighs and groin brown vs. distinct dark brown horizontal band on anterior and posterior parts of thigh, inner surface of shank and inner surface of tarsus extended up to first three toes on upper surface.

The comparison provided above for R. kaikatti is based on the examination of the name bearing types at BNHS but that of R. flaviventris are based on original descriptions provided in Bossuyt and Dubois (2001) and Biju and Bossuyt (2009) since the specimen itself is located outside India. Details of name bearing types examined by authors has been provided in Appendix I and major opposing suite of morphological characters of all other species in Raorchestes found in the Western Ghats except R. flaviventris and R. kaikatti are provided in Appendix II.

Ecology and natural history notes. Two individuals (ZSI/WGRC/V/A/858: one male and one female) of this species were first collected on bushes up to 2 m height along streams on riparian vegetation next to the road in Kakachi by KSS, NAA, TG and RG on 24th January 2011 at 20:30 hrs. Subsequently, on 24th May 2011, a pair (ZSI/ WGRC/V/A/859: one male and one female) in axillary amplexus was observed and collected on forest floor in the same location by KSS and PS from 20:49 hrs to 21:30 hrs. The amplecting pair was carried to laboratory where they were observed for egg laying in a terrestrial enclosure. The amplecting pair dismounted and the female laid six eggs and a few more eggs were visible in the abdomen. The eggs were non-pigmented with jelly mass and measured (2.2 mm, n = 3). However, we did not make any further observation on egg development.

FIGURE 6. Spectrogram of an advertisement call of Raorchestes kakachi sp. nov. (ZSI/WGRC/V/A/ 857) measuring 6.54 sec in duration recorded from Kakachi on 23rd June 2011 at 19:08 hrs. Dominant frequency of this call 2625 Hz, pulse duration 0.05 sec, pulses 9, pulse rate 1.77 sec–1. a. Amplitude; b. Spectrogram and c. Band width.

Between May and June 2011, three individuals were observed and photographed (not collected) to be foraging in the canopy of Cullenia exarillata (32 m) and Diospyros sp. (30 m) trees between 19:00–21:15 hrs in forests around Kakachi and Upper Kodayar. The canopy was accessed at night using modified single rope technique ( Perry 1978). Two calling males were collected from 2 m high vegetation along a stream in Kakachi on 24th June 2011. The calls of these two individuals were recorded for analysis. An amplecting pair was observed the next day (25th June 2011) on the same location on roadside tree at 4 m height from 19:23 hrs–21:30 hrs but did not lay eggs. In another location, a male and female were observed in the sub-canopy (ca. 15 m) of roadside trees. A male Ramanella montana was seen mounting with a female of R. kakachi sp. nov. for about 5 min after which, the pair disengaged in the same location.

A long term monitoring study by KSS in KMTR using automated sound recorders have recorded the species to be vocalizing in the canopy and on the ground. The vocalization begins at about 18:30 hrs and the number of individuals and their vocalizing intensity reaches a peak between 18:00–20:30 hrs. Initially the calls were heard from the canopy and the frogs were detected on the ground at about 19:00 hrs.

Though many individuals of this frog were observed in the canopy in both Kakachi and Upper Kodayar, the individuals described in this paper were collected on ground and on natural vegetation in estate, either before the frog went up into the canopy or after they descended from there.

Advertisement call analysis. Calls were recorded using Nikon D90 DSLR camera within 20–30 cm from calling males at night (19:00–21:30 hrs). The air temperature and humidity at collection time were (23°C and 86% RH, measured using Kestrel 3500®, data logger). Eight calls from two calling males were analyzed using Audacity Ver.1.3 (Beta) and SIGVIEW 32 Ver.2.3.0. Call terminology was based on Kok and Kalamandeen (2008). Each call had 6–9 pulses (treek, treek, treek,…pulses). Average dominant frequency was 2637.25 ± 14.1 Hz (range: 2630–2651 Hz), Call duration was 4.98 ± 0.8 sec (range: 3.4–6.5 sec), inter call duration was 1.46 ± 0.7 sec (range: 0.6–2.2 sec), pulse duration was 0.74 ± 0.07 sec (0.6–0.9 sec), pulse period was 0.05 ± 0.006 sec (range: 0.04–0.07 sec) and pulse rate was 1.54 ± 0.1 sec -1 (range: 1.37–1.75 sec -1). Figure 6.a–c illustrates the amplitude, call spectrum and peak frequency of a single call (ZSI/WGRC/V/A 857). A short video clip of the frog vocalizing can be found on Amphibia web, 2012 (http://tinyurl.com/raorchestes-kakachi).

Figures

FIGURE 2. a. Raorchestes kakachi sp. nov. holotype in life (male, SVL = 25.8 mm; ZSI / WGRC / V / A / 857); b. Paratype in life (female, SVL = 34.1; ZSI / WGRC / V / A / 858). Photographed in type locality by KSS.

FIGURE 3. a – f. Raorchestes kakachi sp. nov. holotype in preservative. a. dorsal view; b. ventral view; c. ventral view of head; d. lateral view of head; e. ventral view of hand; f. ventral view of foot; g. dorso-ventral view of hand in life (female, ZSI / WGRC / V / A / 858) and h. schematic diagram of webbing in feet. All photographs by KSS.

FIGURE 4. a – c. Variations in morphology among males of Raorchestes kakachi sp. nov. from type locality (a & b: not collected, c: 858) d: holotype male calling (857); e. Variation in female (859) & f. amplecting pair (858). Numbers in parenthesis indicate voucher numbers with ZSI / WGRC / V / A as prefix. All photographs by KSS.