Polypedates bengalensis, Purkayastha & Das & Mondal & Mitra & Chaudhuri & Das, 2019

Purkayastha, Jayaditya, Das, Madhurima, Mondal, Kingshuk, Mitra, Shibajee, Chaudhuri, Anir- Ban & Das, Indraneil, 2019, A new species of Polypedates Tschudi, 1838 (Amphibia: Anura: Rhacophoridae) from West Bengal State, Eastern India, Zootaxa 4691 (5), pp. 525-540 : 529-536

publication ID	https://doi.org/ 10.11646/zootaxa.4691.5.6
publication LSID	lsid:zoobank.org:pub:581C9435-F356-4F8E-89CF-80F0AE36CC98
persistent identifier	https://treatment.plazi.org/id/03B087C9-FFB6-143E-FF03-739BFA08F974
treatment provided by	Plazi
scientific name	Polypedates bengalensis
status	sp. nov.

Treatment

Polypedates bengalensis sp. nov.

Figs. 2–6 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 6

Holotype. V/A/ NERC/1448 , mature male, SVL 53.6 mm ( Fig. 2 View FIGURE 2 ). Khordanahala , South 24 Parganas District (22.2 47719°N, 88.144078°E; WGS84 ), elevation 7 m above sea level, collected on 13 June 2018, by Kingshuk Mondal.

Paratypes. (V/A/ NERC/1449 , mature male, SVL 52.1 mm; V/A/ NERC/1450 , mature male, SVL 47.9 mm; collector and date as in holotype. V/A/ NERC/1451 , mature male, SVL 50.9 mm; V/A/ NERC/1452 , mature female, SVL 72.0 mm; V/A/ NERC/1453 , mature male, SVL 51.5 mm; V/A/ NERC/1454 , mature male, SVL 48.2 mm and V/A/ NERC/1455 , mature male, SVL 48.1 mm were collected by Shibajee Mitra on 21 June 2018 from Badu , North 24 Parganas District (22.692860°N, 88.505926°E), elevation 13 m above sea level. GoogleMaps

Diagnosis. A mid-sized Polypedates , SVL range from 47.9–53.6 mm (mean: 50.3 mm) in males and 72.0 mm in the single female specimen. Tympanum large, about three fourth of the size of orbit ( Fig. 3 View FIGURE 3 ). Digits without webbing (rudimentary webbing can be seen between the first and second finger, Fig. 4 View FIGURE 4 ). Inner and outer metacarpal tubercles present, outer one about 65% in length of the inner one. Toe webbed with webbing formula I 1–1 II 0.5–2 III 1–2 IV 2 –0.5V ( Fig. 4 View FIGURE 4 ). An inner metatarsal tubercle present. Tibio-tarsal articulation reaches between eye and nostril. Canthus rostralis steeply concave. A straight angular supratympanic fold runs from behind the eyes to the angle of the jaw. The skin on the forehead co-ossified to the skull, vomerine teeth oblique between the choanae ( Fig 5 View FIGURE 5 ). No dermal fold present on the forearm; thigh with white spots forming a reticulated pattern.

Description of holotype. Body elongate (SVL/HW 3.1); head slightly longer than broad (HW/HL 0.9), relatively deep (HD/HL 0.7). Canthus rostralis concave. Interorbital space flat and wider than upper eyelid (UE/IOS 0.7). The skin on the forehead co-ossified to cranium. An angular supratympanic fold runs from behind the eyes to the angle of the jaw. Nostrils small (ND/EHD 0.2), laterally placed, closer to snout (NS/EN 0.6) than to the eye. Eye horizontally elliptical (EVD/EHD 0.7); tympanum horizontally elliptical (TVD/THD 0.8), more than 4/5 th of the size of the eye, tympanum separated from eye by a small gap (TE 1.2 mm). A straight angular supratympanic fold runs from behind the eyes to the angle of the jaw. Vomerine teeth oblique (30 degrees to body axis) between the choanae, seven in number separated broadly from each other. Tongue lanceolate with bifid tip. Forelimb relatively long (FLL/SVL 0.5), No dermal fold present on forearm; relative length of the fingers are F1 (6.3) <F2 (7.1) <F3 (8.4) <F4 (11.3). Tip of the digits with prominent discs. Inner and outer metacarpal tubercles present, outer ca. 64.5% in greatest length of inner. The nuptial pad is elongated and is on dorsal surface of first finger. Hind limb long (x 1.5 SVL), tibia longer than femur (FL/TBL 0.9), tibio-tarsal articulation reaches between eye and nostril, subarticular tubercle and toe disk distinct, relative toe length: T1 (4.2) <T2 (5.2) <T3 (8.5) <T5 (10.2) <T4 (14.7). Webbing formula of toe I 1–1 II 0.5–2 III 1–2 IV 2 –0.5V. Large, spade-shaped outer metatarsal tubercle present.

Dorsum smooth, lacking tubercles, dorsal region of forelimbs and hindlimbs smooth. Ventral surface of the body granular with enlarged tubercles present in the abdominal region extending up to vent. Ventral surface of the femoral region granulated. Ventral surface of forelimb, tibia and tarsus smooth.

Colour in life (based on type series). Ground colour of dorsum yellowish brown to greenish-brown. A continuous series of 6–9 dark brown blotches extend laterally from behind the eye to vent ( Fig. 3 View FIGURE 3 ). The blotches vary in shape, but are mostly elongate and run parallel to body axis. A maximum of three rows of such blotches can be seen around midbody, and are largest medially. Typically, two triangular shaped blotches in interorbital region, each in contact with upper eyelid ( Fig. 3 View FIGURE 3 ). A dark brown streak runs from behind the nostril to the eye and continues from behind the eye to angle of jaws. Iris golden brown, tympanum dark brown ( Fig. 3 View FIGURE 3 ). Upper lip cream coloured. Dorsal surface in forelimb and hindlimb is lighter compared to colouration of dorsum, dorsum with distinct broad bands of dark brown colour. Back of thigh with yellowish brown blotches, forming a reticulate pattern ( Fig. 6 View FIGURE 6 ). Similar reticulated pattern are present on region between axilla and groin. A narrow dark brown line runs along outer edge of forearm and tarsus. Venter cream-coloured. Gular region yellowish-white, sometimes with a light reticulate pattern.

Colour in preservative. Body colour has turned into a lighter shade compared to the live specimen. The yellow colour of the spots behind the thigh and between axila and groin completely faded, producing a pale off-white appearance. The blotches and stripes are dull in comparison to live specimens.

Etymology. The specific epithet bengalensis is proposed, referring on to the type locality of the species located in the West Bengal State of India.

Suggested vernacular name. The vernacular names suggested for the new species are ‘Khoyeri Daag Gecho Bang’ and ‘Brown Blotched Bengal Tree Frog’, in Bengali and English, respectively.

Bioacoustics. The advertisement call was recorded at an ambient temperature of 34ºC (https://doi.org/10.6084/ m9.figshare.9768059). A typical advertisement call consists of five to eight notes with an average note length of 10.3 ms (max: 14ms, min: 7ms, σ: 2.5) and inter-note interval of 107 ms. (max: 86ms, min: 137ms, σ: 15.3). The call we worked with has nineteen numbers of repetition in a minute. The portion of the call we analyzed consisted of seven notes. Each note comprised of six pulses. Approximate prevalent bandwidth of the calls ranged from 0.5 kHz to 2.5 kHz with a dominant frequency of 1464.25 Hz. The call has only one peak of amplitude ( Fig. 7 View FIGURE 7 ).

Distribution. The new species is known from Khordanahala, South 24 Parganas and Madhyamgram, North 24 Parganas in the State of West Bengal, in eastern India ( Fig. 1 View FIGURE 1 ).

Natural history. All frogs were encountered around residential areas. Calls were heard after sunset and continued till after midnight. The males were seen perched on vegetation, including bamboo, banana and taro leaves, and were calling from a height of ca. 1.2–1.8 m above ground, over stagnant waters bodies (mostly rainwater pools), and amplexus is axillary ( Fig. 8 View FIGURE 8 ).

Comparisons. Polypedates bengalensis sp. nov. genetically differs (16s rRNA) from congeners (0.094 –0.147 uncorrected genetic distance; Table 1); and no sister-group relationship could be uncovered with any single of the congeners with certainty, rather the new taxon is sister-group to a clade containing several species ( Fig. 9 View FIGURE 9 ). Polypedates bengalensis sp. nov. shows skin on the forehead co-ossified to the skull (free in P. assamensis , P. chlorophthalmus , P. colletti , P. cruciger , P. discantus , P. himalayensis , P. maculatus , P. occidentalis , P. subansiriensis , TABLE 1. Uncorrected pairwise distances (%) of the 16s rRNA sequences of Polypedates (P.) and Rhacophorus (R.) used in this study.

P. taeniatus and P. zed ); lack of hour glass pattern on dorsal surface (hour glass pattern on dorsal surface present in P. insularis , P. megacephalus , P. pseudotilophus , P. subansiriensis ); lack of spiny projection from the angle of jaw (a spine at the angle of jaw is present in P. otilophus and P. ranwellai ), iris golden yellow (iris bright green in P. chlorophthalmus ), lack of postcloacal tubercles (2–4 post cloacal tubercle present in P. macrotis ), body with elongated blotches (body without spots in P. cruciger ), palmar tubercles two in number (three palmer tubercles present in P.impresus , P. leucomystax and P. teraiensis ), males with vocal sacs (vocal sac absent in P. macrotis , P. mutus and P. hecticus ). Toes are less webbed in comparison to P. iskandari (web formula for P. iskandari is I 1–1 II 1–2 III 1–2 IV 2–1 V).