Sunday, March 12, 2023

[Herpetology • 2023] Amolops terraorchis • A New Species of Amolops (Anura: Ranidae) representing the morphological ‘Marmoratus Species Group’ from Sessa Orchid Sanctuary, Arunachal Pradesh, Northeast India

Amolops terraorchis 
Saikia, Sinha, Laskar, Shabnam & Dinesh. 2022

Rec. zool. Surv. India. 122(3) 

The cascade-dwelling frog genus Amolops is known for its range of distribution concentrated in China, India, Myanmar and Nepal. The first Amolops species described from India was in 1871, and since then, 11 species have been described from the country. Being morphologically cryptic and with a preference for cascade habitats, identification of Amolops species based on morphology alone is difficult. Although 11 species of Amolops have been described from the country, their genetic data is very poorly represented in the Amolops phylogenetic studies. In one of our efforts of explorations and documenting the Amolops diversity, multiple populations were sampled in Arunachal Pradesh, which was subjected to genetic analysis. Our study has led to the generation of a novel genetic datum for the species Amolops gerbillus, and a report of a new species. Due to shallow genetic divergence between A. yarlungzangbo and A. gerbillus and the close geographic proximity of the type localities, Amolops yarlungzangbo is proposed to be a junior synonym of Amolops gerbillus as per ICZN codes warranting the examination of the type specimens. Additionally, single gene-based phylogeny is presented including the genetic data available for the Indian species of Amolops.

Keywords: Amolops, Eaglenest, Eastern Himalayas, New Species, Sessa Orchid Sanctuary, West Kameng

Field photo of holotype of Amolops terraorchis sp. nov.

Amolops terraorchis sp. nov. 
Sessa Cascade Frog

Field diagnosis: Amolops terraorchis sp. nov. is a member of the morphological Marmoratus species group. The new species can be diagnosed based on the following set of morphological characters: adult male size medium (SVL 38.6-42.6 mm) and adult female size large (SVL 65.8-82.9 mm); head length wider than long; obtusely pointed snout; snout longer than eye length; inter-orbital distance equals upper eyelid width but smaller than internarial distance; tympanum distinct, about 40% of eye length; finger I disc slightly dilated, all discs with circummarginal grooves; tibia longer than femur and foot, about 2/3rd of SVL; tibio-tarsal articulation reaches beyond snout; no supra-tympanic fold; a discontinuous row of small glandular tubercles dorsolaterally

Distribution: Currently, this species is known from two protected landscapes of West Kameng district of Arunachal Pradesh, India – Sessa Orchid Sanctuary and Eaglenest Wildlife Sanctuary.

Type locality of Amolops terraorchis sp. nov. from Sessa Orchid Sanctuary, West Kameng district, Arunachal Pradesh, India.

Etymology: The species epithet is derived from two Latin words – terra meaning ‘land’ and orchis meaning ‘orchid’, meaning ‘from the land of orchids. The name refers to the type collection locality of Sessa Orchid Sanctuary, which is the first such unique protected landscape in India, and most probably in the world, dedicated to the protection and conservation of the rich orchid diversity of the area. Interestingly, with an area of just 100 km2 , the Sessa Orchid Sanctuary harbours an incredible 149 species of orchids including 59 rare and five extremely rare species, with further scope of documenting much more species (Tsering and Rinya, 2020). 

Suggested Common Name: We suggest ‘Sessa cascade frog’ as a common English name for this species.

A male Amolops gerbillus (Annandale, 1912) from Rottom, Kamle district, Arunachal Pradesh, India.

Bhaskar Saikia, Bikramjit Sinha, Mostaque A. Laskar, A. Shabnam and K. P. Dinesh. 2022. A New Species of Amolops (Anura: Ranidae) representing the morphological ‘Marmoratus Species Group’ from Sessa Orchid Sanctuary, Arunachal Pradesh, Northeast India. Rec. zool. Surv. India. 122(3); 303–322.