How a mating call led Indian & German scientists to new green tree frog species in Arunachal

Named after the Patkai hills, it's the first of its kind found in India, and the 6th new frog species found in Namdapha Tiger Reserve. Findings published in Vertebrate Zoology.

Patkai green tree frog | Credit: Vertebrate Zoology

GAURVI NARANG, The Print, 29 May, 2023, New Delhi: A team of Indian and German scientists has discovered a new species of green tree frog in the Namdapha Tiger Reserve in Arunachal Pradesh’s Changlang district — the first of its kind found in the country, and the sixth new frog species in the reserve. 

According to a study published in the German scientific journal Vertebrate Zoology on 26 May, the frog has been named ‘Patkai green tree frog’, after the Patkai Hills, which are part of the Indo-Myanmar hill ranges where the reserve is located.

Researchers from the Dehradun-based Wildlife Institute of India, the Senckenberg Natural History Collections in Dresden, Germany, and the Namdapha Tiger Reserve, first heard the frog’s mating call during an exploration on 14 May, 2022, says the study.  

The frog belongs to the genus Gracixalus — a subspecies of small- to medium-sized frogs.  Although there are 19 species of this genus across Vietnam, Laos, Thailand, southern China and Myanmar, this is the first time it has been discovered in India.

“Protected areas are the cornerstone of wildlife conservation and tiger reserves perhaps are at the top of conservation priority. However, for better management of these protected areas, one needs a detailed inventory of species,” the researchers wrote in their study.  

According to the authors, the discovery of a unique new species might serve as an example for other protected areas, “especially the least explored ones along the eastern borderland of India”. 

“Apart from this, such research can help in transboundary conservation initiatives and future recognition of the area as a UNESCO world heritage site,” they add.

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Behaviour and habitat

According to the authors, they first heard the frog while on a herpetological exploration of the reserve between 6 pm and 12 am on 14 May 2022, and took photographs and collected some samples for study. 

Herpetology is the branch of zoology concerned with the study of amphibians and reptiles.

The newly-discovered Patkai green tree frog breeds in swampy areas during the monsoon season. 

Despite belonging to Gracixalus, the frog looks different from all known species of this genus, the paper said — it’s small, roughly 23-26 mm, has a long head, small nostrils, a green back with irregular brown spots, slender physique, a dark streak across the head and white marks on its side. 

It also has spikes sticking out of its head and back and appears to be closely related to the Gracixalus gracilipes — a species found in China, Thailand and Vietnam. 

Recordings of the male frog’s mating calls showed that they resembled that of insects, according to the study, which adds that “other aspects such as breeding behaviour, oviposition site (the process of depositing or laying eggs) and habitat use of this interesting species need to be studied in future”.

(Edited by Uttara Ramaswamy)