Red-nosed stub-footed toad (Atelopus oxyrhynchus)
|Also known as:||red-nosed stubfoot toad|
|Spanish:||Sapito Arlequin De Merida|
|Size||Male snout-vent length: 3.9 - 4.9 cm (2)|
Female snout-vent length: 4.6 - 5.8 cm (2)
The red-nosed stub-footed toad is classified as Critically Endangered (CR) on the IUCN Red List (1).
The red-nosed stub-footed toad (Atelopus oxyrhynchus) belongs to a genus of tiny, brightly coloured amphibians known as the ‘harlequin frogs’. Species in the genus Atelopus tend to have thin bodies, long legs and slender toes, and unlike most frogs and toads they tend to move by walking rather than hopping (3) (4). The snout is usually pointed and protuberant, and the toes are webbed (4).
Atelopus species have bright colouration and markings, which are thought to serve as a warning to predators that they are poisonous, due to their toxic skin secretions (3) (4). Although very little information is available on the appearance of the red-nosed stub-footed toad, it is likely to share the typically bright yellow to orange colouration of other Atelopus species (3).
The female red-nosed stub-footed toad is larger than the male (2).
The red-nosed stub-footed toad has an extremely limited distribution, being found only in cloud forest in the Cordillera de Mérida in the Venezuelan Andes (1).
A terrestrial species (3), the red-nosed stub-footed toad only inhabits montane cloud forest, at elevations of 2,100 to 3,500 metres (1).
Relatively little is known about the biology of the red-nosed stub-footed toad. It is a diurnal species, active during the day (3) (4), and is thought to live in forest away from water for most of the year. However, during the breeding season it migrates to streams to breed (2).
The red-nosed stub-footed toad begins to move towards its breeding areas in late April or May, with pairs often forming long before the toads move to the spawning area. Spawning occurs in May or June, and in some cases pairs have been known to remain in amplexus for up to 125 days (2). The large, unpigmented eggs of the red-nosed stub-footed toad are laid in chains in streams, where the tadpoles then develop (1) (2). As in other Atelopus species, the eggs are likely to be attached to rocks, and the tadpoles have suckers on the underside of the body which allow them to grip onto rocks in swift currents (3) (4).
The adult red-nosed stub-footed toad feeds on insects, especially beetles, as well as ants, fly larvae, caterpillars, mites and ticks (5).
The red-nosed stub-footed toad has undergone a drastic population decline, with most populations having completely disappeared. The last recorded sighting of this species was in 1994, and subsequent surveys have failed to find any individuals (1).
Habitat loss and degradation due to logging, mining and the expansion of livestock and crop agriculture have had negative impacts on the red-nosed stub-footed toad. There is also an apparent correlation between dry climatic periods, probably caused by El Niño,and drastic population declines in this species (6).
However, the major cause of the decline of the red-nosed stub-footed toad is likely to be chytridiomycosis, a fungal disease of amphibians (1). Amphibians around the world are currently facing an extinction crisis which threatens up to 50 percent of species, and chytridiomycosis is a key driver of many of these declines (7).
Few specific conservation measures exist for the red-nosed stub-footed toad, but some subpopulations are believed to occur, or have occurred, within the Sierra Nevada and Sierra de la Culata National Parks (1).
Surveys are needed to locate any remaining populations of the red-nosed stub-footed toad, and any surviving individuals may then be used to create a captive population, to try and prevent the extinction of this tiny amphibian (1).
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- Amplexus: the mating position of frogs and toads, in which the male clasps the female around the back or waist.
- Cloud forest: a tropical mountain forest with a high incidence of cloud cover throughout the year.
- Diurnal: active during the day.
- El Niño: a natural phenomenon that happens every 4 to 12 years, and lasts for several months, when upwelling of cold, nutrient-rich water does not occur. This causes the warming of ocean surface water off the western coast of South America and causes die-offs of plankton and fish. It also affects Pacific jet stream winds, altering storm tracks and creating unusual weather patterns in various parts of the world.
- 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.
- Larvae: stage in an animal’s lifecycle after it hatches from the egg. Larvae are typically very different in appearance to adults; they are able to feed and move around but usually are unable to reproduce.
- Montane: of mountains, or growing in mountains.
- Spawning: the production or depositing of eggs in water.
IUCN Red List (March, 2012)
- Dole, J.W. and Durant, P. (1974) Movements and seasonal activity of Atelopus oxyrhynchus (Anura: Atelopodidae) in a Venezuelan cloud forest. Copeia, 1974(1): 230-235.
- Wells, K.D. (2007) The Ecology and Behavior of Amphibians. University of Chicago Press, Chicago.
- Savage, J.M. (2002) The Amphibians and Reptiles of Costa Rica: A Herpetofauna between Two Continents, between Two Seas. University of Chicago Press, Chicago.
- Durant, P. and Dole, J.W. (1974) Food of Atelopus oxyrhynchus (Anura: Atelopodidae) in a Venezuelan cloud forest. Herpetologica, 30(2): 183-187.
- García, I.J., Albornoz, R. and La Marca, E. (2005) Perturbaciones climáticas y disminución de Atelopus oxyrhynchus (Amphibia: Anura) en los Andes de Venezuela. Herpetotropicos, 2(2): 63-71.
- Fisher, M.C., Garner, T.W.J. and Walker, S.F. (2009) Global emergence of Batrachochytrium dendrobatidis and amphibian chytridiomycosis in space, time, and host. Annual Review of Microbiology, 63: 291-310.