[Herpetology • 2022] Amolops chanakya & A. tawang • Two New Species of Amolops (Anura: Ranidae) from Arunachal Pradesh, Northeast India under the morphological ‘Viridimaculatus species group'

Amolops tawang  

Saikia, Laskar, Dinesh, Shabnam & Sinha, 2022

तवांग झरना मेेंढक  ||  RecordsofZSI.com/index.php/zsoi/article/view/169417

Photo: Bikramjit Sinha

Abstract

With the descriptions of a large number of Amolops species in the last two decades, the historical reports of Amolops species from India are in a state of flux, resulting in doubts regarding the specific identities of many species of this genus from the country. Due to their morphological crypticity, species belonging to Amolops are most often difficult to identify based only on morphological characters and colour alone. In the recent years, a number of species of this genus have either been described or reported from India, based on both morphological and molecular phylogenetic studies, like Amolops aniqiaoensis, A. adicola, A. indoburmanensis, etc. Herein, we are describing two new species of Amolops, namely Amolops chanakya sp. nov. and Amolops tawang sp. nov. from western Arunachal Pradesh that belong to the morphological ‘Viridimaculatus species group’ based on a combination of morphological character data sets, genetic studies, and geographical distribution.

Keywords: Amolops chanakya sp. nov., Amolops tawang sp. nov., Cascade Frogs, Chanakya, Cryptic Species, Dirang, Eastern Himalaya, Tawang

Class AMPHIBIA Linnaeus, 1758 

Order ANURA Dumeril, 1806 

Family RANIDAE Batsch, 1796 

Genus Amolops Cope, 1865 

Amolops chanakya sp. nov. 

(Chanakya’s Cascade Frog)

 

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 (IUEFOL>ShL), about 2/3rd of SVL; tibio-tarsal articulation reaches up to the nostril; supra-tympanic fold strong; single row of discontinuous roundish tubercles dorso-laterally.

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. 

 

Etymology: The species epithet is a patronym named after Chanakya (also known as Kautilya or Vishnugupta), a 4th 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. 

Live colour image of holotype of Amolops tawang sp. nov. 

(Photo: Bikramjit Sinha).

Amolops tawang sp. nov. 

(Tawang Cascade Frog)

Diagnosis: Amolops tawang sp. nov. is a member of the morphological Viridimaculatus species group isolated in geographical space from its phylogenetic sister species having a distinct morphological set of characters. The new species can be diagnosed based on the following set of morphological characters: adult male size large (SVL 82.5 mm); head wider than long (HW>HL); snout rounded, snout longer than eye length (SL>EL); inter-orbital distance equals the upper eyelid width but smaller than the inter-narial distance (IUE=UEWShL), about 2/3rd of SVL; tibio-tarsal articulation reaches up to snout; supra-tympanic fold strong; dorso-lateral skin granular.

Natural history: The lone specimen of A. tawang sp. nov. was collected during the mid-day from a torrential hill stream with low water volume, which was characterised by large boulders. The specimen was resting under a boulder in a shallow trickle of water. A single specimen of Nanorana liebigii was also collected from the same habitat. 

Distribution: Currently, this species is known only from its type locality in Tawang District, Arunachal Pradesh, India.   

Etymology: The species epithet is a toponym named after the district Tawang, from where the type was collected. Located in the westernmost part of Arunachal Pradesh, Tawang is renowned for Tawang Monastery, which is the largest in India as well as being the birthplace of the 6th Dalai Lama, Tsangyang Gyatso. The species epithet is treated as a noun in apposition to the generic name. Suggested 

Common Name: We suggest Tawang cascade frog as a common English name and तवांग झरना मेेंढक as a common Hindi name for this species.  

Bhaskar Saikia, Mostaque A. Laskar, K. P. Dinesh, A. Shabnam and Bikramjit Sinha. 2022. Description of Two New Species of Amolops (Anura: Ranidae) from Arunachal Pradesh, Northeast India under the morphological ‘Viridimaculatus species group'. Rec. zool. Surv. India. 122(3); 247–266. DOI: 10.26515/rzsi/v122/i3/2022/169417

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