Amolops chanakya, Saikia & Laskar & Dinesh & Shabnam & Sinha, 2022

Saikia, Bhaskar, Laskar, Mostaque A., Dinesh, K. P., Shabnam, A. & Sinha, Bikramjit, 2022, Description of two new species of Amolops (Anura: Ranidae) from Arunachal Pradesh, Northeast India under the morphological ‘ Viridimaculatus species group’, Records of the Zoological Survey of India 122 (3), pp. 247-266 : 250-254

Amolops chanakya sp. nov.

(Chanakya’s Cascade Frog)

Zoobank ID: urn:lsid:zoobank.org:act:22CC1259-3D8E-47E3-ABE9-E8BCE6B46315

Holotype: V /A/ NERC / ZSI/1771 , adult male ( Figure 3 ), collected by Bikramjit Sinha and party on March 13, 2018 from Chakpa Village (N 27.422089; E 92.2190308; alt.: 1794 m), Dirang, West Kameng district, Arunachal Pradesh, India; collected after dusk hours.

Diagnosis: Amolops chanakya sp. nov. is a member of the morphological Viridimaculatus species group isolated in geographical space from its phylogenetic sister species and has a distinct set of morphological characters. The new species can be diagnosed based on the following set of morphological characters: adult male size large (SVL 76.4 mm); head wider than long (HW>HL); snout rounded, longer than eye length (SL>EL); inter-orbital distance less than both upper eyelid width and inter-narial distance (IUE<UEW<IN); tympanum distinct, about 40% of eye length; finger I disk slightly dilated, all disks with circum-marginal grooves, only a hint of groove in finger I; tibia longer than femur and foot (TiL>FOL>ShL), about 2/3 rd of SVL; tibio-tarsal articulation reaches up to the nostril; supra-tympanic fold strong; single row of discontinuous roundish tubercles dorso-laterally.

Description of the Holotype: Adult male (SVL 76.4 mm), body robust, head wider than long (HW>HL), flat above; snout rounded, protruding in lateral view, snout longer than the eye diameter (SL>EL); canthus rostralis distinct, loreal region depressed; inter-orbital distance less than both upper eyelid width and inter-narial distance (IUE<UEW<IN); the nostrils laterally placed, slightly nearer to the eyes (NS>NE); pupil horizontal; tympanum distinct, circular and little depressed, separated from the eye by a distance slightly more than its diameter; pineal ocellus visible; a pair of vomerine teeth situated between the choanae; tongue bilobed. Vocal sac externally visible.

Arms strong, forearm length shorter than the hand length; fingers free, tips ending in disk, finger I disk slightly dilated; all disks with circum-marginal grooves, only a hint of groove in finger I, relative length of fingers I<II<IV<III; sub-articular tubercles prominent, circular; prepollex oval.

Hindlimbs long, tibia longer than femur and foot (TiL>FOL>ShL); toes long and thin, tips of all toes dilated into disks with circum-marginal grooves, toes completely webbed; sub-articular tubercles domed shaped; inner metatarsal tubercle oval shaped, outer absent.

Dorsal skin smooth; a single row of discontinuous roundish tubercles dorso-laterally; laterally granular, supra-tympanic fold strong; ventral skin smooth. The Colouration of the Holotype: (in life) Dorsal color dull brick-red, spotted with irregular cocoa-brown spots, these cocoa-brown spots enclosing a number of smaller dull brick-red spots; laterally spotted with neon yellow; ventral color cocoa-brown. Limbs distinctly banded; thighs with alternating dull brick-red and cocoa-brown (speckled with lighter dots) bands, hind limbs with neon yellow spots laterally ( Figure 3 ). In preservative same as in live condition, except that all the colours are faded ( Figure 4 ).

Condition of the type: The type is in good condition. Ventral incision was made to extract liver tissue which was used in the molecular study.

Natural history: The holotype was collected after the dusk hours from a small hill stream from Chakpa village.

Distribution: Known from its type locality of Chakpa Village, Dirang Administrative Circle, West Kameng district of Arunachal Pradesh, India.

Comparisons: The new species is compared with the other species of Viridimaculatus species group.

From the Indian Viridimaculatus species group, Amolops chanakya sp. nov. differs from A. formosus (in parentheses) in having larger male SVL (vs. smaller), nostril nearer to eye (vs. equidistant), tympanum small, distinct (vs. about the size of finger III disk), TiL>ShL (vs. TiL<ShL), inner-metatarsal tubercles distinct (vs. indistinct), outer metatarsal tubercle absent (vs. present), dorsal color dull brick-red, spotted with irregular cocoa-brown spots (vs. bright green with large dark spots); from A. himalayanus (in parentheses) in having small tympanum but distinct and depressed (vs. slightly visible), tibia 2/3 rd of SVL (vs. almost equal), tibio-tarsal articulation reached up to nostril (vs. beyond the tip of the snout), dorsum dull brick-red, spotted with irregular cocoa-brown spots (vs. olive with darker spots); from A. nidorbellus (in parentheses) having distinct pineal ocellus (vs. barely visible), IUE<UEW (vs. IUE>EUW), external vocal sac visible (vs. absent), dorsal color dull brick-red, spotted with irregular cocoa-brown spots (vs. brown with small, irregular cobalt green spots), ventral cocoa-brown (vs. pale brown with scattered small, white spots); from A. viridimaculatus sensu stricto (in parentheses) in having wider head (vs. longer), tympanum distinct (vs. indistinct), outer metatarsal tubercle absent (vs. present), dorsal color dull brick-red, spotted with irregular cocoa-brown spots (vs. maroon red with large green blotches); from A. tawang sp. nov. (in parentheses) in having smaller male SVL (vs. larger), nostril nearer to the eye (vs. equidistant), IUE<UEW (vs. IUE=UEW), tympanum larger (vs. extremely depressed and small), TYD ≈ TE (vs. TYD= ½TE), external vocal sac distinctly visible (vs. faintly visible), tibio-tarsal articulation reaches up to nostril (vs. snout), dorsum dull brick-red, spotted with irregular cocoa-brown spots (vs. dorsal color olive-green, spotted with large, irregular shaped dark-brown spots), ventral color cocoa-brown (vs. dark, speckled with lighter dots and dashes)

From the Viridimaculatus species group found outside India, Amolops chanakya sp. nov. differs from A. beibengensis (in parentheses) in having head wider than long (vs. HL=HW), tibio-tarsal articulation reached up to the nostril (vs. between nose and eye), vocal sac externally visible (vs. absent), dorsal color dull brick-red, spotted with irregular cocoa-brown spots (vs. dorsum brown with green spots); from A. gyirongensis (in parentheses) in having larger male SVL> 76 mm (vs. <64 mm), vocal sac externally visible (vs. absent); dorsal color dull brick-red, spotted with irregular cocoa-brown spots (vs. bright green with dark brown irregular large spots); from A. kaulbacki (in parentheses) in having larger male SVL> 76 mm (vs. up to 72 mm), IUE<UEW (vs. IUE>UEW), tibio-tarsal articulation reached up to the nostril (vs. beyond snout), vocal sac externally visible (vs. absent), dorsal color dull brick-red, spotted with irregular cocoa-brown spots (vs. green with black spots and marbling); from A. longimanus (in parentheses) in not having a distinctive dorsolateral fold (vs. present), absence of parotid-like swelling above tympanum (vs. present); from A. medogensis (in parentheses) in having smaller male SVL of 76 mm (vs. 95 mm), vocal sac externally visible (vs. absent), dorsal color dull brick-red, spotted with irregular cocoa-brown spots (vs. olive green with brown markings/dark brown with small yellow-green spots); from A. pallasitatus (in parentheses) in having tibio-tarsal articulation reached up to the nostril (vs. posterior eye corner), dorsal color dull brick-red, spotted with irregular cocoa-brown spots (vs. yellow green with irregular dark brown blotches); from A. splendissimus (in parentheses) in having a supra-tympanic fold strong (vs. poorly developed), dorsal color dull brick-red, spotted with irregular cocoa-brown spots (vs. black-brown spangled thickly with bright yellow spots); from A. wangyufani (in parentheses) in having larger male SVL> 76 mm (vs. <70 mm), tibio-tarsal articulation reached up to the nostril (vs. beyond snout), dorsal color dull brick-red, spotted with irregular cocoa-brown spots (vs. brown with sparse green patches).

Etymology: The species epithet is a patronym named after Chanakya (also known as Kautilya or Vishnugupta), a 4 th century BCE Indian polymath and administrator famous for Arthashastra, a Sanskrit treatise on economic policies, statecraft and military strategy. The species epithet is treated as a noun in apposition to the generic name.

Suggested Common Name: We suggest Chanakya’s cascade frog as a common English name and चाणक्य झरना मेंढक as a common Hindi name for this species.

Figures

Figure 3. Live colour image of holotype of Amolops chanakya sp. nov. (Photo: Bikramjit Sinha).

Figure 4. Holotype image of Amolops chanakya sp. nov. in preserved condition (A: dorsal view; B: ventral view).