Small frog with relatively large head. Males attain a snout-vent length of up to 34,7mm, whereas females grow up to 38 mm. The eyes are large and have a vertical slit-shaped pupil. Limbs, fingers and toes are relatively long. There are three metacarpal tubercles. The skin is fairly smooth and shiny. Some larger warts are present along the sides of the back. The coloration is very variable. Usually there are dark green to black spots of variable size and shape on a golden-greenish background. Not seldom there is a black triangle present on the head behind the eyes. The underside is white. There is no clear sexual dimorphism. (Noellert and Noellert 1992).
Distribution and Habitat
Country distribution from AmphibiaWeb's database: Spain
Alytes muletensis is endemic to Mallorca a small island off the eastern coast of Spain. The species was first described from fossils in the upper pleistocene as Baleaphryne muletensis Sanchiz and Adrover, 1977. It was believed to have gone extinct following the colonization of the island by man about 4000BC, until larvae and young frogs were found in the inaccessible limestone gorges of the Serra de Tramuntana (Buley and Garcia 1997). The species is found in only ten brooks (torrentes) in the Serra de Tramuntana. The area receives an annual rainfall of 1000 to 2000mm. Water temperatures range from 9ºC to 22ºC. The frogs hide in crevices and under stones in groups of up to 5 individuals.
Life History, Abundance, Activity, and Special Behaviors
Mating behaviour is similar to other Alytesspecies. Male call sounds like a high melodic "pi..pi..pi..". Like in the rest of the genus Alytes, the males of this species carry the eggs in strings around their ankles until the tadpoles hatch. Males bearing eggs are found mostly in May and June. The eggs in this species are larger than those of other Alytes, but smaller in number. The eggs measure 5.4 to 7mm in diameter and a clutch contains 7 to 12 eggs. The first larvae hatch in the beginning of May. Total length upon hatching is 18mm, and the larvae grow up to 76mm in a few weeks. Metamorphosis occurs mostly in June. There is no hibernation period. These frogs are mostly active at night (Noellert and Noellert 1992).
Trends and Threats
Alytes muletensis is among the most important species in Europe from a conservation viewpoint. The small occupied area, the low number of adults (between 500 and 1500 pairs in all, according to various estimates) and the evidence of a formerly much larger range - all bring this species to the highest rank in the list of animals deserving special protective measures. In fact, state and regional laws have forbidden the capture, keeping or killing of this species since 1980. Listed on the Red Data Book of Spanish Vertebrates as endangered, the species' rarity has also been acknowledged by all international conservation agreements signed by Spain. The habitat was put forward as a Biogenetic Reserve to the council of Europe, and the species has been subject to two recovery programs, one of them involving breeding of captive animals. In spite of that, the future of the species looks bleak. Dangers are too high, and populations too scarce and small to withstand a serious threat. So far, animals introduced by man have been the main enemies of the toad. Especially dangerous is the snake Natrix maura, an efficient predator of adults and tadpoles, introduced by man in Roman times. Competition for food with Rana perezi could be another factor of the past range decrease. Today, Alytes muletensis lives only in places which both these species, the snake and the frog, cannot reach. The heavy tourism in Mallorca and the increase of urban population have resulted in a strong need for water, to be taken from the only available place on the island, the mountains of the north. There are already proposals to dam some of the rivers where Alytes muletensis lives, and tap the water for urban needs. It may be that breeding in captivity, which has already allowed repopulating on some sites, will become, in the long term, the only hope for survival of the species (Paris 1997). Translocation of Alytes muletensis have had some measure of sucess (Seigel, 2001)
Possible reasons for amphibian decline
Drainage of habitat
Predators (natural or introduced)
Buley, K.R. and Garcia, G. (1997). ''The recovery programme for the Mallorcan midwife toad Alytes muletensis: An update.'' Dodo: Journal of the Jersey Wildlife Preservation Trusts, (33), 80-90.
Gasc, J.-P. (1997). Atlas of Amphibians and Reptiles in Europe. Societas Europaea Herpetologica, Bonn, Germany.
Nöllert, A. and Nöllert, C. (1992). Die Amphibien Europas. Franckh-Kosmos Verlags-GmbH and Company, Stuttgart.
Seigel, R. A. and Dodd, C.K., Jr. (2001). ''Translocations of amphibians: proven management method or experimental technique?'' Conservation Biology, 16(2), 552-554.
Stumpel-Rieks, S. E. (1992). Nomina Herpetofaunae Europaeae. AULA-Verlag, Wiesbaden.
Written by Arie van der Meijden (amphibia AT arievandermeijden.nl), Research associate, Museum of Vertebrate Zoology, UC Berkeley
First submitted 1999-09-22
Edited by Vance Vredenburg (2006-04-05)
Feedback or comments about this page.
Citation: AmphibiaWeb: Information on
amphibian biology and conservation. [web application]. 2014. Berkeley, California:
(Accessed: Apr 25, 2014).
AmphibiaWeb's policy on data use.