Corsican painted frog  (Discoglossus montalentii)

The Corsican painted frog is classified as Near Threatened (NT) on the IUCN Red List (1).

The Corsican painted frog (Discoglossus montalentii) has a slender body with an acutely rounded snout. Like other painted frog species, the Corsican painted frog has a disc-shaped tongue and round or triangular pupils (4) (5). The fingers of this species are short and unwebbed, whereas the toes are long (4). The tip of the fourth finger is wider than the base (3).

The skin of the Corsican painted frog is smooth and shiny with a scattering of small warts (5). There are two colour pattern varieties of this species. One variety is uniformly plain coloured, either dark brown, dark grey, reddish or red-brown, while the other has dark brown spots (3) (6). The belly of the Corsican painted frog is yellowish-white (3). During the breeding season, the male Corsican painted frog has large nuptial pads on the fingers, chin and belly, which are swollen areas that help the male to grip onto the female during amplexus (4).

The tadpoles of the Corsican painted frog have tails which are longer than the body and are rounded at the tip. The upperparts of the tadpoles are blackish or dark brown, while the underparts and the muscular section of the tail are usually darkly pigmented (7).

The male Corsican painted frog has a call that has been described as a quiet, rolling laugh (4). The call of this species is more musical than in other frog species (3), described as a harmonious (5) ‘poop…poop…poop’ (3). It is thought that this distinctive call evolved as an adaptation to living in the same area as the closely related Tyrrhenian painted frog (Discoglossus sardus). The evolution of such different calls, or ‘acoustic partitioning’, ensures that the two species do not interbreed by only attracting mates of their own kind (5).

The Corsican painted frog is one of just three amphibian species endemic to the island of Corsica, France (2). It is mainly found in the central part of the island, from Corte and Cervione in the north, down to Porto-Vecchio in the south (1) (6) (8).

The Corsican painted frog is a mountain-dwelling species (2), which strongly favours areas in high-altitude pristine woods and forests with running waters (1) (2) (3). It is particularly associated with the edge of rocky, precipitous streams (1) (4) (8).

The Corsican painted frog has been recorded at elevations of between 300 and 1,900 metres above sea level, and it is not found in coastal lowlands (1) (3) (8).

The Corsican painted frog is generally a nocturnal species, although it is also known to be active during the day (4). This species frequently sits in shallow water with its head just above the surface, but the Corsican painted frog is very agile when it needs to be, often leaping between boulders in watercourses (3).

Breeding takes place in shallow water, with the male Corsican painted frog grasping the female around the waist during amplexus. Fertilisation is external, after which the female will lay between 500 and 1,000 eggs in slow-moving streams (4), generally under rocks and stones (1). The tadpoles of the Corsican painted frog develop in these streams for three to eight weeks before undergoing metamorphosis (4).

The Corsican painted frog appears to have a mixed feeding strategy, and generally feeds on a variety of very small terrestrial and freshwater invertebrates. Aquatic invertebrates are usually captured from the surface or in shallow water (2), as the disc-shaped tongue is relatively short and cannot be flicked out of the mouth to catch flying insects (5).

The exact status of the Corsican painted frog is not known (6), but it is thought that predation by introduced species is causing a slow decline in population numbers (1).

The Corsican painted frog is listed on Appendix II of the Bern Convention, which aims to conserve the wild flora and fauna of the European Continent (9). This species is also on Annexes II and IV of the EU Habitats Directive, which means that it is in need of strict protection and requires the designation of special areas of conservation to ensure its future survival (10).

Other measures proposed for the conservation of the Corsican painted frog include further research into assessing its range and population size, as well as the status of its habitat. Identifying, establishing and maintaining new protected areas within suitable habitat would also be beneficial to this species (6).

Learn more about amphibians:

• IUCN/SSC Amphibian Specialist Group:
  http://www.amphibians.org/
• AmphibianArk:
  http://www.amphibianark.org/
• Gascon, C., Collins, J.P., Moore, R.D., Church, D.R., McKay, J.E. and Mendelson III, J.R. (2005) Amphibian Conservation Action Plan. The World Conservation Union (IUCN), Gland, Switzerland. Available at:
  http://www.amphibianark.org/pdf/ACAP.pdf

Find out more about the habitat of this species:

• ARKive - Mediterranean Basin:
  http://www.arkive.org/eco-regions/mediterranean-basin/