In pictures: Four new species of burrowing frogs discovered in the Western Ghats

Scientists studying the Western Ghats in southern India have discovered four new species of burrowing frogs in this biodiversity hotspot.

The frogs belong to the genus Fejeverya, all of which make their homes underground. This made them particularly hard to find even though they are a fairly common group of frogs, said Sonali Garg, who undertook this study – a six-year long field exploration – as a part of her doctoral research at the University of Delhi.

Research on frogs species in the Western Ghats has grown in leaps and bounds over the past decade. Between the years 2006-’15, a total of 1,581 species of amphibians were described globally. Of these, 103 species were described from the Western Ghats region alone. In a span of 10 years, the number of amphibian species known in the Western Ghats has nearly doubled. Garg’s PhD research previously found seven new species of night frogs, of which four were less than 14 mm in length. Garg’s mentor and supervisor, SD Biju, has discovered over 80 species of frogs so far, earning himself the nickname “frogman”.

Of the 40-odd species of frogs that belong to genus Fejerverya, only one was previously known to have a burrowing lifestyle – the Rufescent Burrowing Frog. This species was given the “Least Concern” conservation status category on the International Union for Conservation of Nature’s Red List – an inventory of the global conservation status of biological species – since it was considered to be abundantly distributed throughout the Western Ghats.

However, Garg’s study revealed otherwise. It found that the Rufescent Burrowing Frog is, in fact, restricted to a much smaller region in Karnataka and adjoining parts of Kerala. After sampling 16 populations of frogs in other parts of the Western Ghats that looked similar to the Rufescent Burrowing Frog, scientists who were part of the study formally identified four different species entirely – based on differences in DNA, physical appearance and variations in their calls. These new species are the Neilcox Burrowing Frog (Fejervarya neilcoxi), the Manoharan Burrowing Frog (Fejervarya manoharani), the CEPF Burrowing Frog (Fejervarya cepfi) and the Kadar Burrowing Frog (Fejervarya kadar).

Hard to find

Since the frogs rarely surface through the year, they have not been properly documented, said Garg. “Knowledge on them is very less as of now,” she said. “We still don’t know much about their lifestyle or what exactly they eat.” Only seven or eight other species of burrowing frogs, across all groups, are known till date.

Usually hidden either in their burrows, or under leaf litter or large stones, these frogs can be spotted only during the mating season at the beginning of the South West monsoon. “We can see them for a very short period of time in a year, for less than two or three weeks,” said Garg. “If you miss the chance you have to wait an entire year to go back and study them.”

Biju usually names newly discovered species after people and organisations who have worked towards the conservation of biodiversity, who have helped him in his research, or after places that need to be conserved. For instance, the Neilcox Burrowing Frog is found in Parambikulam Tiger Reserve in Palakkad district of Kerala. It has been named after Dr Neil Cox of the US-based Biodiversity Assessment Unit in recognition of his role in preparing the International Union for Conservation of Nature’s Red List assessment of global amphibian species.

The Manoharan Burrowing Frog, found in Kerala’s Agasthyamala hills, has been named after TM Manoharan, the former principal chief conservator of forests of Kerala. Manoharan had offered financial support to Biju in the early phases of his scientific career.

Need for conservation

Of the four species found, two could face serious threats from human-induced environmental pollution, said the scientists.

The first is the CEPF Burrowing frog, named after the Critical Ecosystem Partnership Fund in the US. This frog is found in Maharashtra’s popular hill-station Amboli, which is often frequented by tourists, increasing the risk of loss of habitat.

The other is the Kadar Burrowing Frog, which was discovered in the Vazachal forest of Kerala. The species was named after the indigenous Kadar tribe that lives in the region. The tribe is currently protesting against a mega-hydroelectric project proposed on the Athirappilly falls in the region. If the project goes through, the existence of a number of wildlife species endemic to the Western Ghats, such as the Kadar Burrowing Frog, could be threatened.

“If you need to conserve biodiversity, you must first know what you are conserving,” said Biju. “In case of the burrowing frogs, we need to know their ecological niche and their habitat requirements. They are not found near water like other frogs. Unless we know where they are found, we cannot conserve them.”