Corsican painted frog
(Discoglossus montalentii)
The Corsican painted frog is only found in mountain streams in the pristine forests of central Corsica.  Due to its similarity in appearance to the more common Tyrrhenian painted frog (Discoglossus sardus), also present on Corsica, not much is known about how many D. montalentii exist within its limited range.  The two species overlap in some areas, but have evolved different foraging strategies.  D. montalentii also has a very different mating call to other species of painted frog, which prevents interbreeding.  Painted frogs are so-called because of their variety of colour patterns, complicating the identification of species within this group.  They have been evolving independently of any other lineage for over 200 million years, making them older than many species of dinosaur.

Urgent Conservation Actions
Endemic to Corsica.
Evolutionary Distinctiveness
Order: Anura
Family: Alytidae
The Alytidae are an ancient family found in Europe, the Middle East and Northwestern Africa, and are comprised of the midwife toads (Alytes) and painted frogs (Discoglossus).  Overall, this family is now named after the midwife toads.  The family name was formerly Discoglossidae or ‘disc-tongued frogs’ because, unlike the slender tongues of many amphibians, midwife toads and painted frogs possess a round and flattened tongue.  They diverged from the fire bellied toad lineage and all other amphibians about 210 millions years ago at the end of the Triassic period, around the same time that the first primitive mammals started to appear.  The midwife toad family therefore evolved at the feet of some of the earliest dinosaurs, and survived the dinosaur’s demise nearly 150 million years later.

Within the family Alytidae, the painted frogs diverged from the midwife toads about 155 million years ago, about 5 million years before the first birds started to appear in the fossil record.  Painted frogs are more different from their closest relatives in terms of evolutionary time than kangaroos are to elephants, as they started to evolve independently about 10 million years before the common ancestor of these two mammal groups.

The number of species in this group has been the subject of debate since the discovery of Discoglossus in the 1830s.  For over a hundred years it was contested whether the two described forms, D. pictus and D. sardus, even deserved subspecies status.  Developments in molecular biology allowing the study of genetic make-up have revealed a high level of divergence within the group, and have identified a number of new species.  It is currently being debated whether there are six or seven species within the Discoglossus genus. 

It is thought that the Corsican painted frog was the first to split off from the rest of the painted frog group, colonising Corsica when prehistoric land bridges connected it to Sardinia and the mainland.  Recent estimates date this divergence event to between 10 and 15 million years ago, around the time of the splitting of the gorilla lineage from chimpanzees and humans.     
Unlike their closest relatives the midwife toads, which are relatively stocky and toad-like, painted frogs have classic frog features such as a slim waist, long legs and webbed toes on their hind feet.  Their pupils are round, triangular or ‘upside-down teardrop’ shaped, and their skin is generally smooth and shiny with small but visible warts.  The name comes from the variety of colour variations and patterns seen in the group; some are plain in colour whilst others have stripes, spots, bands and blotches of varying tones.

Corsican painted frogs can be light or dark brown, light or dark grey, reddish, red-brown, light brownish grey or olive greenish, and have a yellow-white belly and a scattering of warts over both sides of the body.  Some have dark brown spots and bands, others have few or none.  They are very similar in appearance to the more widespread Tyrrhenian painted frog Discoglossus sardus, but can be distinguished by minor morphological differences like finger shape and leg length.  Due to their cryptic forms, the two have only recently been recognised as separate species, and as such very little is known about how many D. montalentii populations exist.
The disc-shaped tongues seen in this group of frogs are not long and free to be flicked out of the mouth to capture insects in mid-air.  Instead, invertebrate prey items are gobbled straight into the mouth whilst the frog is on land or in water.  The Corsican painted frog is sympatric with the Tyrrhenian painted frog D. sardus, meaning that they are found in overlapping geographic areas but do not interbreed.  In some localities they are even syntopic, meaning that not only do their ranges overlap but they can actually share the same habitat within the same geographic area.  Studies have shown that differences in foraging strategy explain how the two close relatives can coexist, as D. sardus mainly captures prey items whilst on land, while D. montalentii takes prey from land and water in similar proportions.

Another adaptation to living side by side with a closely related species is the evolution of a very distinct call, which ensures that the two species only attract mates of their own kind.  A study comparing the calls of four painted frog species found that D. pictus, D. sardus, D. galganoi and D. montalentii can all be distinguished by their call, but that D. montalentii has the call that differs the most from all the others.  The call of D. montalentii has a harmonious structure (the others are unharmonious) and is more similar to that of the fire bellied toads of the family Bombinatoridae.  ‘Acoustic partitioning’ of this kind prevents the two species from interbreeding.
The Corsican painted frog lives in high altitude streams in pristine woods and forests.  Although its distribution overlaps with that of the Tyrrhenian painted frog D. sardus, there seems to be some degree of differentiation in habitat preference, with D. montalentii preferring running water at higher elevations and D. sardus preferring slow running or stagnant water at lower elevations.  The differences in foot morphology that distinguish D. montalentii from D. sardus are thought to be an adaptation to living in the more rocky areas.
This species is endemic to the French island of Corsica, and has a very limited range.  It is mainly found at high altitudes in the centre of the island, from Corte and Cervione in the North to Porto-Vecchio in the South.  It has been recorded at elevations between 300 and 1,900 metres above sea level.
Population Estimate
Population Trend
It is not known whether or not this species is in decline, so it is listed as Near Threatened in the 2006 IUCN Red List of Threatened Species due to its small range.
There are currently no known threats to D. montalentii, but very little research has been carried out into this species.  Introduced predator and competitor species are listed as possible future threats by the IUCN Red List of Threatened Species.
Conservation Underway
D. montalentii is listed as ‘strictly protected’ in EU legislation, under Appendix II of the Bern Convention and Annex IV of the Natural Habitats Directive.
Conservation Proposed
Research into the population status of this species is needed in order to ascertain whether or not it is in decline.  Suitable habitat is limited and so must be maintained if D. montalentii is to survive.
AmphibiaWeb           http://amphibiaweb.org/

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Glaw, F. and Vences, M. 1991. Bioacustic differenciation in Painted frogs (Discoglossus). Amphibia-Reptilia 12: 385-394.

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Lanza, B., Cei, J. M. and Crespo, E. 1975. Immunological evidence for the specific status of Discoglossus pictus Otth, 1837 and D. sardus Tschudi, 1837, with notes on the families Discoglossidae Günther, 1858 and Bombinidae Fitzinger, 1826 (Amphibia Salientia). Monitore Zoologico Italiano (N.S.) 9: 153-162.

Lanza, B., Nascetti, G., Capula, M. and Bullini, L. 1984. Genetic relationships among West Mediterranean Discoglossus with the description of a new species (Amphibia Salientia Discoglossidae). Monitore Zoologico Italiano (N.S.) 18: 133-152.

Martinez-Solano, I. 2004. Phylogeography of Iberian Discoglossus (Anura: Discoglossidae). Journal of Zoological Systematics and Evolutionary Research 42(4): 298-305.

Miaud, C. and Cheylan, M. 2006. Discoglossus montalentii. In: IUCN 2008. 2008 IUCN Red List of Threatened Species. www.iucnredlist.org. Downloaded on 09 January 2009.

Salvido, S., Sindaco, R., Emanueli, L. 1999. Feeding habits of sympatric Discoglossus montalentii, Discoglossus sardus and Euproctus montanus during the breeding season. Herpetological Journal 9:163-167.

San Mauro, D. 2004. Phylogenetic relationships of discoglossid frogs (Amphibia: Anura: Discoglossidae) based on complete mitochondrial genomes and nuclear genes. Gene 343(2): 357-366.

Veith, M. and Martens, H. 1997. Discoglossus montalentii. In: Gasc et al. (eds.) Atlas of Amphibians and Reptiles in Europe. Societas Europa Herpetologica, Muséum National D’Histoire Naturelle, Paris.

Distribution dataset:  IUCN 2008. 2008 IUCN Red List of Threatened Species. http://www.iucnredlist.org

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