Scientific discovery

In pictures: Seven new species of night frogs discovered in the Western Ghats

Four miniature species are less than 14 mm long.

The latest discoveries in the amphibian world are tinier than the average fingernail.

After six years of trudging through the rainforests of the Western Ghats in southern India, scientists have discovered seven new endemic species of Nyctibatrachus, or night frogs. Four of these species are hardly 14 mm in length. The study outlining this discovery was published on Tuesday.

The insect-like calls of the newly-discovered night frogs species deceived scientists on several occasions.

“For a long time, we heard these calls while we were walking through certain forest patches and thought they were insects till we spotted them under leaf litter,” said Sonali Garg, who undertook the study as part of her doctoral research at the University of Delhi. These miniature species were locally abundant, she said, but they had probably been overlooked by previous researchers because of their extremely small size and secretive habitats, apart from their deceptive insect-like calls.

According to the study, night frogs represent an ancient group of frogs that spread across the Indian landmass approximately 70 million to 80 million years ago. The first species belonging to this group was documented in 1882, and since then the group has been relatively well-studied.

These seven species add to existing knowledge about 28 species that have been identified so far as belonging to the ancient lineage of night frogs. This frog genus is endemic to the Western Ghats and is found near the marshy forests and mountain streams of five states – extending from the southern tip of Tamil Nadu across the tropical landscape of Kerala, Karnataka and Goa till northern Maharashtra.

“These frogs are very important links to understand how evolution took place over time,” said Garg. “In terms of evolutionary studies, these are the remaining relics of ancient frogs that lived on this landscape.”

Seven new discoveries: A. Radcliffe’s Night Frog (Nyctibatrachus radcliffei), B. Athirappilly Night Frog (Nyctibatrachus athirappillyensis), C. Kadalar Night Frog (Nyctibatrachus webilla), D. Sabarimala Night Frog (Nyctibatrachus sabarimalai ), E. Vijayan’s Night Frog (Nyctibatrachus pulivijayani), F. Manalar Night Frog (Nyctibatrachus manalari), G. Robin Moore’s Night Frog.  (Photo credit SD Biju).
Seven new discoveries: A. Radcliffe’s Night Frog (Nyctibatrachus radcliffei), B. Athirappilly Night Frog (Nyctibatrachus athirappillyensis), C. Kadalar Night Frog (Nyctibatrachus webilla), D. Sabarimala Night Frog (Nyctibatrachus sabarimalai ), E. Vijayan’s Night Frog (Nyctibatrachus pulivijayani), F. Manalar Night Frog (Nyctibatrachus manalari), G. Robin Moore’s Night Frog. (Photo credit SD Biju).

Enormous diversity

Of the 28 species of night frogs, 13 species were identified and documented over the last five years. With every discovery, scientists have realised just how diverse the group was. In 2007, Garg’s mentor SD Biju, who has discovered over 80 species of frogs so far, found India’s smallest frog species Nyctibatrachus minimus, that is just 10 mm in length. Popularly known as the frogman, Biju and his team went on to find 12 other species belong to the night frogs group in 2011. The largest species of night frog found, Nyctibatrachus grandis, is 77 mm in length and lets out a deep croaky call.

Manalar Night Frog (Nyctibatrachus manalari). (Photo credit: SD Biju).
Manalar Night Frog (Nyctibatrachus manalari). (Photo credit: SD Biju).

Not only do night frogs show immense diversity in terms of size and calls, but also in reproductive behaviour. Across the 7,500 species of frogs found across the world, researchers have observed six mating positions. But in 2016, a study also found a species of night frog, known as the Bombay night frog, which practices a seventh mating position – the dorsal straddle – a technique which is not found in any other frog species till date.

“This is a very interesting group of organisms to study since it is so diverse in every way,” said Garg. “Its DNA gives us information of a much longer time frame. It is evolutionarily significant information if we want to understand why certain frogs are found in small regions, or distributed widely, or to explain their diversity.”

The 12.2 mm long Robinmoore’s night frog (Nyctibatrachus robinmoorei) sitting on an Indian five-rupee coin (24 mm diameter) is one of the new species discovered from the Western Ghats mountain ranges in peninsular India. (Photo credit SD Biju).
The 12.2 mm long Robinmoore’s night frog (Nyctibatrachus robinmoorei) sitting on an Indian five-rupee coin (24 mm diameter) is one of the new species discovered from the Western Ghats mountain ranges in peninsular India. (Photo credit SD Biju).

Significance of miniatures

Of the 35 night frogs found in the Western Ghats so far, seven are miniature, less than 18 mm in length.

“In group after group of amphibians, miniatures have evolved,” said David B Wake, an evolutionary biologist at the University of California, Berkeley, who has studied miniaturisation in amphibians over many years. “We have been slow to understand this because the miniatures often look like juveniles of common larger forms and have been overlooked.”

Wake explained that miniaturised species often occur in environments that are not usually the favoured habitat of larger frogs. For instance, in the case of the new species found by Garg, the miniature frogs are more terrestrial and occur in leaf litter unlike the larger ones that are found largely near streams.

“Also, in salamanders and in groups of frogs in many parts of the world, the miniatures have abandoned the tadpole stage,” said Wake. “Eggs develop directly into miniatures of the adults and the eggs are laid on land. This frees them from reliance on water and expands ecological and evolutionary opportunities.”

The miniature frogs found by the team, however, are known to go through the tadpole stage. But the team has observed certain other adaptive changes across the new species. While the larger frogs by the streams had webbed feet used for swimming and sticking onto slippery surfaces, this was not found in miniature frogs.

“There was little webbing of the feet in the miniature frogs, probably because they did not need life in water,” said Garg. “This indicates that they are adapting to a terrestrial habitat.”

Manalar night frog (Nyctibatrachus manalari), a 13.1 mm miniature-sized frog discovered from a fragmented forest patch adjacent to tea plantations in the southern Western Ghats. (Photo credit SD Biju).
Manalar night frog (Nyctibatrachus manalari), a 13.1 mm miniature-sized frog discovered from a fragmented forest patch adjacent to tea plantations in the southern Western Ghats. (Photo credit SD Biju).

Conservation and names

Although night frogs are quite common across the Western Ghats, they face considerable threats from human activity.

“While new species are being identified, the known ones are moving towards extinction,” said Biju. He said that frogs are already threatened with extinction in one-third of the Western Ghats. He said of the seven new species found, five required immediate priority for conservation since they were all found outside the protected forest zone.

One of the new species – the Athirappilly night frog – was discovered close to Kerala’s Athirappilly falls, where a mega hydroelectric project is proposed to be set up.

Athirappilly night frog (Nyctibatrachus athirappillyensis), new species discovered from areas adjoining the Athirappilly waterfall, site for a proposed hydroelectric project. (Photo credit: SD Biju).
Athirappilly night frog (Nyctibatrachus athirappillyensis), new species discovered from areas adjoining the Athirappilly waterfall, site for a proposed hydroelectric project. (Photo credit: SD Biju).

Another species, which Biju and Garg have named the Sabarimala night frog was found in the vicinity of the Sabarimala temple, a pilgrim site located inside the Periyar Tiger Reserve in Kerala. “These species were purposely named after their collection localities in order to highlight the threats they might be facing due to anthropogenic disturbance,” said Biju.

Sabarimala Night Frog (Nyctibatrachus sabarimalai), a 12.3 mm miniature-sized frog found in close vicinity of the Sabarimala temple in Kerala. (Photo credit SD Biju).
Sabarimala Night Frog (Nyctibatrachus sabarimalai), a 12.3 mm miniature-sized frog found in close vicinity of the Sabarimala temple in Kerala. (Photo credit SD Biju).
Support our journalism by subscribing to Scroll+ here. We welcome your comments at letters@scroll.in.
Sponsored Content BY 

Following a mountaineer as he reaches the summit of Mount Everest

Accounts from Vikas Dimri’s second attempt reveal the immense fortitude and strength needed to summit the Everest.

Vikas Dimri made a huge attempt last year to climb the Mount Everest. Fate had other plans. Thwarted by unfavourable weather at the last minute, he came so close and yet not close enough to say he was at the top. But that did not deter him. Vikas is back on the Everest trail now, and this time he’s sharing his experiences at every leg of the journey.

The Everest journey began from the Lukla airport, known for its dicey landing conditions. It reminded him of the failed expedition, but he still moved on to Namche Bazaar - the staging point for Everest expeditions - with a positive mind. Vikas let the wisdom of the mountains guide him as he battled doubt and memories of the previous expedition. In his words, the Everest taught him that, “To conquer our personal Everest, we need to drop all our unnecessary baggage, be it physical or mental or even emotional”.

Vikas used a ‘descent for ascent’ approach to acclimatise. In this approach, mountaineers gain altitude during the day, but descend to catch some sleep. Acclimatising to such high altitudes is crucial as the lack of adequate oxygen can cause dizziness, nausea, headache and even muscle death. As Vikas prepared to scale the riskiest part of the climb - the unstable and continuously melting Khumbhu ice fall - he pondered over his journey so far.

His brother’s diagnosis of a heart condition in his youth was a wakeup call for the rather sedentary Vikas, and that is when he started focusing on his health more. For the first time in his life, he began to appreciate the power of nutrition and experimented with different diets and supplements for their health benefits. His quest for better health also motivated him to take up hiking, marathon running, squash and, eventually, a summit of the Everest.

Back in the Himalayas, after a string of sleepless nights, Vikas and his team ascended to Camp 2 (6,500m) as planned, and then descended to Base Camp for the basic luxuries - hot shower, hot lunch and essential supplements. Back up at Camp 2, the weather played spoiler again as a jet stream - a fast-flowing, narrow air current - moved right over the mountain. Wisdom from the mountains helped Vikas maintain perspective as they were required to descend 15km to Pheriche Valley. He accepted that “strength lies not merely in chasing the big dream, but also in...accepting that things could go wrong.”

At Camp 4 (8,000m), famously known as the death zone, Vikas caught a clear glimpse of the summit – his dream standing rather tall in front of him.

It was the 18th of May 2018 and Vikas finally reached the top. The top of his Everest…the top of Mount Everest!

Watch the video below to see actual moments from Vikas’ climb.

Play

Vikas credits his strength to dedication, exercise and a healthy diet. He credits dietary supplements for helping him sustain himself in the inhuman conditions on Mount Everest. On heights like these where the oxygen supply drops to 1/3rd the levels on the ground, the body requires 3 times the regular blood volume to pump the requisite amount of oxygen. He, thus, doesn’t embark on an expedition without double checking his supplements and uses Livogen as an aid to maintain adequate amounts of iron in his blood.

Livogen is proud to have supported Vikas Dimri on his ambitious quest and salutes his spirit. To read more about the benefits of iron, see here. To read Vikas Dimri’s account of his expedition, click here.

This article was produced by the Scroll marketing team on behalf of Livogen and not by the Scroll editorial team.