It is believed that King Mahābalī visits Kerala for one day every year and crores of Malayalis celebrate this day as Onam. Now, researchers at the Kerala Forest Research Institute (KFRI) have decided to honour a little-known frog from Kerala’s Western Ghats by naming it Maveli (short for Mahābalī) and petitioning the government to recognise it as the state frog. If approved, Kerala would be the first state in India to have an official frog or amphibian.
Commonly known as the purple or pig-nosed frog, this robust, dark purple species is elusive and spends most of its time under the soil.
“We decided to name it Maveli since much like the asura king, it comes out of the soil once a year. It comes out during monsoons, typically to mate and moves to fresh streams to lay eggs,” Sandeep D, an EDGE fellow and PhD student at KFRI who has sent the proposal to make Maveli the state frog, told TNM.
Known in academic circles by the scientific name Nasikabatrachus sahyadrensis, the purple frog was discovered in 2003 by SD Biju, from the Tropical Botanic Garden, and Franky Bossuyt, from the Free University of Brussels.
Unlike other frogs found in India, this purple species has unique features, including a peculiar set of limbs and a pointy nose to survive underground. It remains endemic to the Western Ghats and is found in Kerala – right from the Agasthya hills and all the way to Wayanad.
The Africa connect
Back in 2003, the discovery of the purple frog created much excitement within the research community as it had huge evolutionary significance, Sandeep recalls.
“The frog belongs to the family of Sooglossidae and its closest relatives are found in the Seychelles island, near Madagascar, Africa,” he says.
The fact that the frog’s nearest relatives are found in Africa, zoologists believe is proof of the Gondwanaland Hypothesis, which posits that the Indian land mass was once part of Africa and the whole region made up a supercontinent.
Physical features and mating
The adult purple frogs have calcified shovel type features on their hind feet to dig tunnels inside the soil. A strong and pointy nose to help with movement is also one of their noticeable features.
According to a research paper header by Dr Anil Zacharia, which Sandeep is part of, the frogs feed on ants, white ants and soil mites found underground. Their breeding pattern too is rather unique, the paper observed.
“Every year when the conditions are ideal for mating, the male and female purple frogs mate on trees or on the ground, in a mating position called Amplexus, where the males sit on top of the females. After this the females go to nearby streams to lay their eggs,” Sandeep says.
Each female frog can lay around 2,000-3,000 eggs, he adds.
“They lay eggs typically after the first rains, inside shallow seasonal springs which are brought to life by the first rain water. This is clever as they avoid all kinds of aquatic predators which join the spring only at a later stage,” Sandeep says.
The eggs hatch into tadpoles and live inside rock crevices in the streams for a 100 days.
“Their tadpoles have oral suckers to grab on to rocks. This way, these babies can withstand torrential streams as they suck on to the rocks and stay put,” Sandeep states. The physical features of these tadpoles, including the suckers, were published in a 1917 paper by a British zoologist, Nelson Annandale and an Indian zoologist, C. R. Narayan Rao.
After 100 days, the tadpoles metamorphose into baby frogs and move underground. They then return once a year to mate and breed, just like their parents.
Proposal to make it the state frog
As per the IUCN’s Red List, the purple frog is placed in the fourth highest category of threatened species.
It is also ranked third in the list of threatened amphibians under the EDGE (Evolutionarily Distinct and Globally Endangered) list. This out of 8,007 amphibians in the world.
“The purple frog is considered an important species globally and it is endemic to Kerala. Making it a state frog can help boost its conservation,” Sandeep added.
Conserving the frog has other benefits: It could also lead to protecting the aquatic ecosystem of the Western Ghats, including tiny species living in the springs and pools.
“Since this frog only breeds in the seasonal springs, it becomes an umbrella species. If we have to conserve the frog, we have to conserve the whole aquatic ecosystem of the springs,” Sandeep adds.
A proposal has been sent to members of the State Wildlife Advisory Board and a decision is expected to be taken in June.