Blue-eyed bush frog (Philautus neelanethrus)
|Size||Male snout-vent length: 2.3 - 3 cm (2)|
- The Western Ghats is home to more than 90 endemic Philatus species, with even more thought to be undiscovered.
- Frogs in the Philautus genus do not lay eggs in water, instead developing directly into miniature adults from eggs laid on the forest floor.
- The blue and golden eyes of the blue-eyed bush frog make it a very distinctive species.
- The blue-eyed bush frog was first described as recently as 2007.
The blue-eyed bush frog is classified as Endangered (EN) on the IUCN Red List (1).
The blue-eyed bush frog (Philautus neelanethrus) is a small, distinctive frog which gains its common name from the bright blue ring running around the edge of its protruding, golden eyes. Its scientific name, neelanthrus, means ‘blue eyes’ in Sanskrit, a historical local dialect (2).
The skin of the blue-eyed bush frog varies between yellow and cream and there are brown dots and blotches on the upperside of the body, indicating areas of granulation which can differ in intensity between individuals. The skin on the underside of the body has round, white blotches and is also granulated. The skin on the wide head of the blue-eyed bush frog features circular brown spots, and the snout is pointed and protrudes forward beyond the mouth (2).
The colouration of the male blue-eyed bush frog becomes more yellow and vivid during the breeding season. The female blue-eyed bush frog is likely to be slightly larger than the male (2).
Vocalisations are made by the blue-eyed bush frog during the breeding season, using the unpigmented vocal sac in the throat. Calls usually begin as a shrill ‘treek’ and are followed by a recurring ‘tink’ note (2).
The blue-eyed bush frog is endemic to India, where it is found in the state of Karnataka in the southwest of the country (1).
The blue-eyed bush frog inhabits shrubby areas in evergreen and moist deciduous forests, as well as Myristica swamps, which are dominated by Myristica plants and are a favoured habitat of this species (1) (2). Within its habitat this small amphibian is found at elevations between 500 and 700 metres (2).
The blue-eyed bush frog avoids open or barren areas where there is rocky terrain or where the area has been disturbed by forest fires or human activities such as agricultural growth or urbanisation (1) (2).
Very little is known about the biology of the blue-eyed bush frog. Like other species in the Philautus genus, it is thought to breed by ‘direct development’, with the female laying eggs on the ground rather than into water (1) (2). The eggs are usually laid underneath stones or leaves and development then occurs within the egg, which eventually hatches into a miniature version of the adult, rather than passing through a tadpole stage (3).
The blue-eyed bush frog has lost a great amount of suitable habitat due to dam construction, agriculture and urbanisation. Many of the remaining habitats are fragmented and ecological barriers prevent movement of individuals between the forest fragments (1) (2). The formation of fragmented habitats has left most populations of the blue-eyed bush frog at high risk of extinction due to inbreeding stress and has increased their vulnerability to invasive species. Any further reductions in habitat area could compromise the future survival of this species (2).
Some areas within the range of the blue-eyed bush frog are protected, including the Sharavathi Valley Wildlife Sanctuary, Mookambika Wildlife Sanctuary and Kudremukh National Park, offering it a certain degree of protection. More research is required into the range, habitat requirements and populations of the blue-eyed bush frog, and investigations are needed into how threats can be addressed to conserve this colourful amphibian (1).
Find out more about the blue-eyed bush frog:
- Gururaja, K.V. et al.(2007) A new frog species from the central Western Ghats of India, and its phylogenetic position. Zoological Science, 24: 525-534.
Find out more about amphibian conservation:
More information on conservation in the Western Ghats:
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- Deciduous forest: forest consisting mainly of deciduous trees, which shed their leaves at the end of the growing season.
- Endemic: a species or taxonomic group that is only found in one particular country or geographic area.
- Evergreen forest: forest consisting mainly of evergreen trees, which retain leaves all year round. This is in contrast to deciduous trees, which completely lose their leaves for part of the year.
- Genus: a category used in taxonomy, which is below ‘family’ and above ‘species’. A genus tends to contain species that have characteristics in common. The genus forms the first part of a ‘binomial’ Latin species name; the second part is the specific name.
- Inbreeding: the breeding of closely related individuals. An inbred population usually has less genetic variability and this is generally disadvantageous for its long-term survival and success.
IUCN Red List (July, 2012)
- Gururaja, K.V. et al. (2007) A new frog species from the central Western Ghats of India, and its phylogenetic position. Zoological Science, 24: 525-534.
- Bossuyt, F. and Dubois, A. (2001). A review of the frog genus Philautus Gistel, 1848 (Amphibia, Anura, Ranidae, Rhacophorinae). Zeylanica, 6: 1-112.