Rhacophorus calcadensis Ahl, 1927

Biju, S. D., Kamei, Rachunliu G., Mahony, Stephen, Thomas, Ashish, Garg, Sonali, Sircar, Gargi & Suyesh, Robin, 2013, Taxonomic review of the tree frog genus Rhacophorus from the Western Ghats, India (Anura: Rhacophoridae), with description of ontogenetic colour changes and reproductive behaviour, Zootaxa 3636 (2), pp. 257-289 : 263-271

Rhacophorus calcadensis Ahl, 1927

Kalakkad Tree Frog (Das and Dutta 1998)

( Figures 1B , 2A , 3, 3A–B , 4A–F , 6A ; Tables 1–3)

Original name and description. Rhacophorus calcadensis Ahl, 1927 , Zur Systematik der asiatischen Arten der Froschgattung Rhacophorus . Sitzungsberichte der Gesellschaft Naturforschender Freunde zu Berlin, 1927:46.

Replacement name for Rhacophorus beddomi Boulenger, 1882 . Name-bearing type. Holotype, NHM 1947.2.8.43 (ex BMNH 82.2.10.24), by monotypy, an adult male. Type locality. “Calcad” (Kalakkad), Tirunelveli district, Tamil Nadu, India. Junior secondary homonym of Ixalus beddomi Günther, 1876 “1875”. Current status of specific name. Va li d n a m e, a s Rhacophorus calcadensis Ahl, 1927 . Synonym. Rhacophorus beddomii Boulenger, G.A. 1882 , Catalogue of the Batrachia Salientia s. Ecaudata in the Collection of the British Museum, Ed. 2:469.

Other material studied/observed. KERALA: Kollam district, Pandimotta, SDBDU 2011.291 (adult male), collected by SDB on 13 September 2011; Thiruvananthapuram district, Athirimala, SDBDU 569 (adult male), collected by SDB on 11 June 2002; Palakkad district, Kaikatti, SDBDU 2010.258–2010.259 (two adult males), collected by SDB on 29 May 2010; Idukki district, Kadalar, SDBDU 2012.864 (adult male), collected by SDB on 12 July 2011. TAMIL NADU: Tirunelveli district, Ooth, SDBDU 2042 and SDBDU 2043 (two adult males), collected by SDB on 20 June 2002; Upper Kodayar (Kalakkad Mundanthurai Tiger Reserve), SDBDU 2005–2007 (three adult males), collected by SDB on 15 November 2008; Coimbatore district, Andiparai Shola, Valparai, SDBDU 1156–1157 (two adult males), collected by SDB on 8 June 2010.

Diagnosis. Rhacophorus calcadensis can be distinguished from known congeners by the following combination of characters: (1) medium male adult size (SVL 33.2–47.0 mm); (2) brown dorsal colour with grey to yellowish-brown webbing between fingers and toes in life ( Figure 3A–B ); (3) finger and toe discs well developed (FD III 2.1 ± 0.4 mm, FW III 0.9 ± 0.3 mm, N = 20; TD IV 1.8 ± 0.3 mm, TW IV 0.7 ± 0.3 mm, N = 20); (4) webbing extensive, reaching the base of the disc in inner and outer side of finger III; (5) thick dermal fringe from base of pad of toe V extends along lateral edge of tarsus to heel where it develops into broad flange with lateral projecting calcar on lateral edge of heel; (6) toe webbing extensive, reaching beyond distal subarticular tubercle on either side of toe IV ( Figure 4E, F ); (7) dorsal skin with prominent granular projections ( Figure 4A ).

Comparison. Rhacophorus calcadensis can not be confused with other currently known members of the Western Ghats due to its dark brown or yellowish-brown dorsal skin colouration and extensive webbing on both fingers and toes.

The original description by Boulenger (1882) and subsequent description by Ahl (1927) were rather brief. For a more comprehensive understanding of this species morphology we provide a redescription of the holotype.

Redescription of holotype (all measurements in mm): Medium sized frog (SVL 46.5); head longer than wide (HL 16.2; HW 14.6; MN 12.5; MFE 9.8; MBE 5.9); outline of snout in dorsal and ventral view pointed, snout (SL 7.3) longer than horizontal diameter of eye (EL 5.2); loreal region obtuse, canthus rostralis indistinct; nostril oval and closer to tip of snout than eye (NS 3.0; EN 3.5); interorbital area (IUE 4.0) wider than upper eyelid (UEW 3.5); distance between posterior margins of eyes (IBE 11.8) 1.4 times the distance between anterior margins of eyes (IFE 8.4); tympanum ( TYD 2.4) distinct, rounded, its distance to eye (TYE 0.9) less than half of tympanum diameter, supratympanic fold distinct, from posterior corner of upper eyelid to near the shoulder; pineal ocellus absent; vomerine ridge horizontal in position, near anterior corner of choanae; space between the two ridges is less than the length of the ridge; tongue notched; median lingual process absent. Forearm (FAL 7.9), shorter than hand (HAL 12.0); fingers with dermal fringes, presence of dermal flaps on border of forelimbs; finger discs with distinct circummarginal grooves, third finger disc 2 times wider than finger (FD III 1.9; FW III 0.9); webbing extensive, on finger I, II, III and IV to base of disc ( Figure 4C, D ); relative length of fingers: (I <II <IV <III); subarticular tubercles prominent, oval, all present; prepollex distinct, oval; one palmar tubercle, oval, indistinct; nuptial pad well developed. Hind limbs moderately long, shank length (SHL 21.3) shorter than thigh (TL 22.2), and longer than the foot length (FOL 16.4); distance from heel to tip of toe IV (TFOL 25.9); thick dermal fringe from base of pad of toe V extends along lateral edge of tarsus to heel where it develops into broad flange with lateral projecting calcar on lateral edge of heel; webbing extensive, on toe I, to base of disc; toe II, to base of disc (inner and outer); toe III, to base of disc (inner and outer); toe IV, to above distal subarticular tubercle (both outer and inner); and toe V, to base of disc; relative length of toe: I <II <III <V <IV; finger discs with distinct circummarginal grooves, fourth toe disc 1.8 times wider than toe (TD IV 1.8, TW IV 1.0); subarticular tubercles prominent, oval, all present; inner metatarsal tubercle distinct, oval; outer metatarsal tubercle, supernumerary tubercles and tarsal tubercle absent.

Skin of snout and between eyes prominently granular with spinular tips, upper eyelids tuberculate; anterior parts of back coarsely wrinkled with keratinised spines throughout the body, posterior parts of back with minute granules and skin folds ( Figure 4A ); ventral side, throat, chest, belly prominently granular (tree frog belly skin), thigh granular, forelimbs smooth; a conspicuous squarish dermal fold above the anal opening.

Colour of holotype. In preservation. Dorsally dark grey with irregular dark patches; ventral side light grey, thigh darker than belly and chest, hand, feet and webbing dark grey ( Figure 4 ). In life (SDBDU 2005). Dorsally dark grey, brownish-grey, with or without yellow tinge ( Figure 3A, B ) and scattered inconspicuous patches; lateral side light yellowish-grey; limbs dorsally light brown, forelimbs, hind limbs and fingers with faint brown cross bands; flanks light grey with dark spots; ventral side light grey, webbing dark grey.

Secondary sexual characters. Male, nuptial pads present.

Variation. Measurements of 20 male specimens, including holotype, are given in Table 2. Rhacophorus calcadensis shows considerable variation in morphometric characters, especially snout to vent length (33.2–47.0 mm) in adult males. Though PCA of the ordination plot ( Figure 5 ) indicates no clear demarcation between the populations based on their morphometric characters, population from Kadalar (Idukki, Kerala) shows relatively less overlapping characters. However, the combination of low genetic distance and lack of distinct morphological differences do not warrant this population to be named as a new species.

Distribution and natural history. This species is known from Athirimala, Pandimotta, Kadalar, Kaikatti, Nelliyampathy, in Kerala and Kakachi, Kalakkad, Ooth, Upper Kodayar, Andiparai Shola, Valparai in Tamil Nadu ( Figure 6A , Table 1). The species occurs at elevations between ca. 200 to 1400 m asl. Specimens from Upper Kodayar, Kaikatti, Nelliyampathy and Athirimala were found in evergreen forest patches at height of about six to seven meters above ground level. The population from Ooth was collected from disturbed forest fringes close to tea plantations at about three meters height. Specimens (SDBDU 2012.863, SDBDU 2012.811) from Kadalar were collected from leaves and stems of wild cardamom plants and shrubs on the roadside ca. one meter above ground level between 19:30 to 21:00 hours. During the breeding period (June–August) animals aggregated near marshy areas covered with vegetation.

Distribution Coordinates Altitude Reference Latitude (ºN) Longitude (ºE)

Rhacophorus calcadensis

KERALA

Kollam dist.

Pandimotta 8.8269 77.2164 1222 Present study

Palakkad dist.

Kaikatti, Nelliyampathy 10.5372 76.6764 965 Present Study

Idukki dist.

Kadalar 10.1311 76.9986 1429 Present study

Thiruvananthapuram dist

Athirimala 8.6178 77.2297 993 Present study

TAMIL NADU

Coimbatore dist.

Valparai 10.3669 76.9697 600 Present study

Tirunelveli dist.

Kakachi 8.5442 77.4278 1200 Vasudevan et al. 2001

“Calcad” (= Kalakkad) 8.7050 77.3136 198 Boulenger 1882; Ahl 1927

Ooth, Tirunelveli 8.5917 77.5031 1100 Present study

Upper Kodayar, Tirunelveli 8.5292 77.3656 1346 Present study

......continued on the next page TABLE 1. (Continued)

Kollam dist.

Kattalappara 8.9178 77.0953 130 Present Study Pandimotta 8.8264 77.2122 1221 Present Study Pathanamthitta dist.

Moozhiyar 9.3161 77.0683 566 Present Study

......continued on the next page ......continued on the next page Rhacophorus pseudomalabaricus

KERALA

Palakkad dist.

Figures

FIGURE 5. Ordination plot of Principal Component Analysis (PCA) for morphometric variables studied in four populations of Rhacophorus calcadensis. Percent variance explained by each PC axis is given in parentheses.

FIGURE 1. A – G. Leaf nest types and multimale mating in the Western Ghats Rhacophorus. A – C. Leaf nest types. A. Type 1: Single leaf rolling— Rhacophorus lateralis; B – C. Type 2: Multiple leaves nest— R. calcadensis, R. malabaricus, R. pseudomalabaricus; D – G. Multimale mating. D – E. R. lateralis on vegetation. F. R. malabaricus on vegetation. G. R. malabaricus on ground.

FIGURE 2. A – D. Photographs showing colour and marking of juveniles and adults in the Western Ghats Rhacophorus. A. R. calcadensis; B. R. lateralis; C. R. malabaricus; D. R. pseudomalabaricus.

FIGURE 3. A – H. Rhacophorus of the Western Ghats. A – B. R. calcadensis; C – E. R. lateralis; F – G. R. malabaricus; H. R. pseudomalabaricus.

FIGURE 4. A – F. Holotype of Rhacophorus calcadensis, NHM 1947.2. 8.43 (ex BMNH 82.2.10.24), from " Calcad ” (Kalakkad): A. dorsal view; B. lateral view of head; C. ventral view of hand; D. schematic illustration of webbing on hand; E. ventral view of foot; F. schematic illustration of webbing on foot.

FIGURE 6. A – D. Distribution maps of the four Rhacophorus species in the Western Ghats. A. R. calcadensis; B. R. lateralis; C. R. malabaricus; and D. R. pseudomalabaricus. Positioning of symbols is approximate; see Table 1 for coordinates.