Purple frog
(Nasikabatrachus sahyadrensis)

The purple frog was originally thought to belong to a unique family called Nasikabatrachidae, but was incorporated as a subfamily into the larger Sooglossidae family in 2006. Its closest relatives are the Seychelles frogs, the ancestors of which were present on the Indo-Madagascan land mass with the purple frog’s predecessors when it broke away from the supercontinent of Gondwana 120 million years ago. Formally discovered in 2003, the purple frog spends most of the year underground, surfacing only to breed during the monsoon. This species is threatened by ongoing forest loss for coffee, cardamom and ginger plantations.

Urgent Conservation Actions
Work with local people to encourage ecologically sensitive farming techniques; conduct more research on this elusive species to develop a Conservation Action Plan.
Western Ghats, India.
The scientific name for the purple frog (Nasikabatrachus sahyadrensis) derives from the Sanskrit word nasika (nose) referring to the pointed snout, the Greek word batrachus (meaning frog), and Sahyadri which is the local name of the Western Ghats mountain range where it was found.

The purple frog was officially discovered by Franky Bossuyt from the Vrije Universiteit Brussel (Free University of Brussels) and S.D. Biju from the Tropical Botanic Garden and Research Institute in Palode, India in 2003. However, it was well-known to the local people before this.

The recording of the purple frog as a new species to science 2003 prompted one researcher, Blair Hedges of Pennsylvania State University, US, to describe the discovery as "a once-in-a-century find". It is thought to be the sole representative of a family of frogs called the Nasikabatrachidae, which is the first new family of frogs to be discovered since 1926!

The purple frog from the southern Western Ghats may be the only known amphibian species in India that is a fully underground forager. All other burrowing frogs are either open burrow feeders or day-time burrow dwellers that are forage above ground at night.
Associated Blog Posts
24th Nov 14
The purple frog (Nasikabatrachus sahyadrensis) is currently listed as the world’s 4th most Evolutionarily distinct and globally endangered amphibian spec...  Read

25th Jul 11
This frog in not only extraordinary in its appearance but also in the way it lives.  Unlike most frogs the purple frog (Nasikabatrachus sahyadrensis) spends...  Read

27th May 10
The Purple frog (Nasikabatrachus sahyadrensis) is a flagship species for conservation in India. Its distribution is restricted to two states in peninsular In...  Read

5th May 09
Ashish Thomas, our first amphibian EDGE Fellow, tells you here a bit more about his chosen species and what he is doing towards its conservation. The Ind...  Read

7th Jan 09
One of our focal EDGE amphibians – the purple frog (Nasikabatrachus sahyadrensis) – has been caught on camera for the first time by EDGE-affiliated resea...  Read

Evolutionary Distinctiveness
Order: Anura
Family: Sooglossidae

The purple frog used to be considered the only surviving member of an ancient amphibian family called the Nasikabatrachidae, but in 2006 this family was incorporated into the Sooglossidae. Up until around 120 million years ago in the early Cretaceous period, India was joined to the eastern part of the ancient southern supercontinent Gondwana, which subsequently split apart into Australia, Antarctica, India, Madagascar and the Seychelles over millenia of movement of the earth’s plates. The closest relatives of the purple frog are four tiny frog species found in the Seychelles in the Sooglossidae family. In their phylogenetic study of the purple frog in 2003, S. D. Biju and Franky Bossuyt (respectively of the Tropical Botanic Garden and Research Institute, Kerala and the Free University of Brussels) reported that the origin of the Sooglossidae/Nasikabatrachidae lineage occurred around 182 million years ago. It is thought that these two amphibian lineages diverged an estimated 134 million years ago form a common ancestor that inhabited Gondwana prior to the break up of this land mass. These frogs were therefore sharing the earth with the dinosaurs for 70 million years and started to evolve independently before the common ancestor of the elephant and the human.

The ancestors of the Seychelles frogs and the purple frog were present on the Indo-Madagascan land mass as it broke away from Gondwana and drifted through the movement of the earth’s plates for over 50 million years. Around 65 million years ago the Cretaceous/Tertiary boundary, the Seychelles split away from India and the ensuring plate movements separated the purple frogs from their closest relatives by around 2,500 km of Indian Ocean. The purple frog is therefore the only representative of a lineage that has been evolving independently for over 130 million years, has survived the break up of a continent and the extinction of the dinosaurs.

The purple frog is a relatively large burrowing frog with a distinct, bloated or plump appearance. The head is conical and short in comparison with the rest of the body, and has a white, protruding snout. The fore- and hind-limbs are short, ending in partially webbed feet with rounded toes and each hind foot possesses a large, white wart-like growth, most likely used for digging. The eyes are small, rounded, and have a horizontal pupil. This species has smooth, dark purple skin that fades into grey along the stomach. Purple frogs reach a total length of about 7 cm.
The purple frog spends most of the year underground, surfacing only for about two weeks during the monsoon season in order to mate. It lives 1.3-3.7m below ground and the frog's reclusive fossorial (digging or burrowing) lifestyle is what caused the species to escape earlier detection by biologists. It comes to the surface for a few weeks a year to breed in temporary and permanent ponds and ditches. During the breeding season, local people reported seeing purple frogs in the vicinity of water pools or at the sides of the swelling streams in pairs clasping each other, especially at the beginning of the monsoon season. During mating, the male clasps the female from behind just above the legs in a behaviour termed “inguinal amplexus”. The bloated shape of both male and female purple frogs, and the smaller size of the male, may mean that males partially glue themselves onto females using sticky skin secretions, as occurs in “short-headed frogs” in the family Brevicipitidae. Eggs are laid in water that hatch into tadpoles, often in ponds close to streams.

The diet of the purple frog predominantly consists of termites, and this species has a narrow mouth with a small gape, preventing it from catching and consuming larger prey items. Its strong head and pointed snout permits it to penetrate underground termite niches, and a fluted tongue may allow this species to suck up its prey from subterranean burrows. With its poor vision, this frog presumably depends on smell and tactile cues to detect and locate prey. It also consumes ants and small worms.

The burrowing and mound-building activities of termites increase the rate of percolation of rainwater and aeration of both the top and subsoil keeping the underground soil temperature low and the moisture content high. It may therefore benefit burrowing amphibians like the purple frog to live in close proximity to termite colonies, which improve the quality of their habitat as well as providing a food source. In India, the purple frog from the southern Western Ghats may be the only known amphibian species that is a fully underground forager. All other burrowing frogs are either open burrow feeders or diurnal burrow dwellers that are open ground feeders in the night.

Purple frogs require damp, loose soil to borrow into, and may dig themselves fully into appropriate soil within 3 to 5 minutes. When placed on hard ground, pebbled- or gravel-strewn soil, or areas with a thick mat of weeds, purple frogs are unable to borrow effectively and go in search of cover. The hind limbs have strong feet with wart-like structures that are primarily used for digging. This frog burrows downwards using its hind limbs like spades, throwing the soil over its back. They rest underground in a horizontal position with the limbs tucked under the body, although they do not remain idle underneath the soil, especially when foraging for their prey.
The first purple frog was officially discovered in disturbed secondary forest near a cardamom plantation. It has also been found in disturbed secondary forest contiguous with montane evergreen forest. It presumably occurs in undisturbed forest as well and apparently does not survive in open, completely clear habitats. This species requires fairly loose, damp, well-aerated soil, especially in close proximity to termite colonies.
This species is endemic to the Western Ghats in India, and is known from only two localities in the Idukki District in the Cardomom Hills, Kerala at an altitudinal range of 850 - 1,000m above sea level. These two areas are Kattapana and near Idukki town. It might occur more widely, but it seems that other reported localities probably refer to currently undescribed species.
Population Estimate
The purple frog is thought to be a rare species, although it is very hard to find which makes any population estimate difficult to determine. Only 135 individuals have so far been observed, and of these only three have been females. The plantation workers within the range of this species have reported that this frog is uncommonly found when they are cutting trenches during the monsoon period (June to October).
Population Trend
The purple frog is thought to be in decline by the IUCN Red List of Threatened Species.
The purple frog is listed as Endangered in the IUCN Red List of Threatened Species because its extent of occurrence is less than 5,000 km sq., all individuals found are in fewer than five locations, and there is a continuing decline in the extent and quality of its habitat in the Cardomom Hills, Western Ghats.
The main threat to the purple frog is believed to be ongoing forest loss for coffee, cardamom, ginger and other species for cultivation.
Conservation Underway
It has not yet been found in any protected areas, although its range is an integral part of the peripheral hilly area that adjoins the Silent Valley National Park. There are no specific conservation measures ongoing for this species.

This project aims to discover more about the ecology of this elusive and recently described frog.

Conservation Proposed
The conservation of suitable habitat for this species should involve working with local plantation owners to encourage ecologically sensitive farming techniques. Establishing a reserve for this species, or extending the boundary of the Silent Valley National Park to encompass part of the range of the purple frog could be beneficial if the protect area is appropriately managed. More research into the environmental requirements and range of this species, in addition to regular population surveys, are also vital components of any conservation project for the purple frog, and all information collected should be used to develop a Conservation Action Plan for this species and its habitat.

Developing an environmental education programme for the communities, farmers and plantation workers within the range of the purple frog would help increase local knowledge and pride in this species, especially if it can be made a symbol of local biodiversity. This could also enable local stakeholders to become involved in conserving through learning about more ecologically sensitive land uses and how to set aside some areas for this species.
Associated EDGE Community members

Biju is a systematic biologist working on amphibians

Karthik is the coordinator and field scientist of a project which aims to find out more about the elisive purple frog.

Ashish Thomas is working on one of the most bizarre and fascinating frog – Nasikabatrachus sahyadrensis.

GWild will wear ONLY 12 outfits in 12 months for 12 threatened animals to fundraise for their conservation.

AmphibiaWeb: Information on amphibian biology and conservation [web application]. 2006. Berkeley, California: AmphibiaWeb. Available: . Accessed: 08 December 2006.

Biju, S.D. and Bossuyt, F. 2003. New frog family from India reveals an ancient biogeographical link with the Seychelles. Nature 425: 711-714.

Biju, S.D. 2004. Nasikabatrachus sahyadrensis. In: IUCN 2006. 2006 IUCN Red List of Threatened Species. . Downloaded on 16 May 2007.

Duellman, W. E. and Trueb, L. 1986. Biology of Amphibians. McGraw-Hill, New York.

Dutta, S.K., Vasudevan, K., Chaitra, M.S., Shanker, K. and Aggarwal, R.K. 2004. Jurassic frogs and the evolution of amphibian endemism in the Western Ghats. Current Science 86(1): 211-216.

Frost, Darrel R. 2006. Amphibian Species of the World: an Online Reference. Version 4 (17 August 2006). Electronic Database accessible at: . American Museum of Natural History, New York, USA.

Frost, D. R., Grant, T., Faivovich, J., Bain, R.H., Haas, A., Haddad, C. F. B., De Sá, R.O., Channing, A., Wilkinson, M., Donnellan, S.C., Raxworthy, C.J., Campbell, J.A., Blotto, B.L., Moler, P., Drewes, R.C., Nussbaum, R.A., Lynch, J.D., Green, D.M., and Wheeler, W.C. 2006. The Amphibian Tree of Life. Bulletin of the American Museum of Natural History 297: 1-370.

Halliday, T. and Adler, C. (eds.). 2002. The new encyclopedia of reptiles and amphibians. Oxford University Press, Oxford.

Hedges, S.B. 2003. The coelacanth of frogs. Nature 425: 669-670.

IUCN, Conservation International and NatureServe. 2006. Global Amphibian Assessment. . Accessed on 08 December 2006.

Obst, F.J., Richter, K. and Jacob, U. 1984. The Completely Illustrated Atlas of Reptiles and Amphibians for the Terrarium. T.F.H. Publication Inc., N.J., U.S.A.

Radhakrishnan, C., Gopi, K.C. and Muhamed Jafer Palot. 2007. Extension of range of distribution of Nasikabatrachus sahyadrensis Biju & Bossuyt (Amphibia: Anura: Nasikabatrachidae) along Western Ghats, with some insights into its bionomics. Current Science 92(2): 213-216.

Roelants, K., Gower, D. J., Wilkinson, M., Loader, S. P., Biju, S. D., Guillaume, K., Moiau, L. and Bossuyt, F. 2007. Global patterns of diversification in the history of modern amphibians. Proceedings of the National Academy of Sciences 104: 887-892.

if you can provide new information to update this species account or to correct any errors, please email us at info@edgeofexistence.org

Forum comments
  1. markS

    This thing may be ugly, but certainly worth protecting. The first and foremost golden rule of animal protection is protection of their habitat. Our global agriculture, cattle raising, and deforestation initiatives are the main causes in too many of these destruction of habitats.

    Posted 7 years ago #
  2. jbpatlanta

    That is one ugly frog. I must say purple is such an unusual color. My son really liked looking at it. He loves all reptiles. His one question was "Why is it Purple?"

    How many of these are there in the world today?

    Posted 7 years ago #
  3. cert sheets

    Wow. Thank you for a really insightful post.

    Posted 7 years ago #
  4. real answers

    Thanks for sharing this post

    Posted 7 years ago #
  5. Anonymous

    its ugly

    Posted 8 years ago #
  6. Anonymous

    this is useful

    Posted 8 years ago #
  7. Sally Wren
    EDGE Team

    Yes - this frog is unique, truly a one of a kind species!

    However, there are other frogs which have completely independently evolved to fill a similar ecological niche (meaning that they live a similar lifestyle) burrowing for most of the year and only coming out after heavy rains to mate. An example that comes to mine is the most evolutionarily distinct of all amphibians, the Mexican burrowing toad (http://www.edgeofexistence.org/amphibians/species_info.php?id=1355).

    Strange that there should be two purple burrowing frogs in the world!

    Posted 8 years ago #
  8. Anonymous

    Is it the only frog of it's type found?

    Posted 8 years ago #
  9. Anonymous

    hi good job! i like those purple frogs!!

    Posted 8 years ago #

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