Description
Female: 22-28 mm, Male: 18-22 mm. Dorsum uniformly black without blotches. Belly black with red and/or yellow blotches. Interdigital web poorly developed. Throat dark. Sexual dimorphism is not evident. This species could be easily confused with Melanophryniscus montevidensis.

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Argentina, Brazil, Paraguay, Uruguay

View distribution map in BerkeleyMapper.

This species inhabits grasslands, open savannas and some areas with rocky soils. Widespread in Pampas grasslands (South America).

Life History, Abundance, Activity, and Special Behaviors
These diurnal toads are active throughout the year and they are explosive breeders. They reproduce in temporary ponds, following heavy rains. The advertisements calls have two components: a repeated whistle, followed by a train of vibrations. During amplexus females release about one hundred eggs in several immersion events. This species exhibits a defensive behaviour ("Unkenreflex").

Trends and Threats
M. atroluteus is a common species in Uruguay in habitats with extensive cattle raising. Intensive livestock could affect reproductive habitat quality (i.e. hard soils - compactation).

Possible reasons for amphibian decline

General habitat alteration and loss
Habitat modification from deforestation, or logging related activities
Habitat fragmentation

References

Achaval, F., and Olmos, A. (2003). Anfibios y reptiles del Uruguay Ed. Graphis. Serie Fauna N°, Montevideo, Uruguay.

Klappenbach, M. A., and Langone, J. A. (1992). ''Lista sistemática y sinonímica de los anfibios del Uruguay con comentarios y notas sobre su distribución.'' Anales del Museo Nacional de Historia Natural de Montevideo (2a Serie), 8, 163-222.

Kwet, A., Maneyro, R., Zillikens, A., and Mebs, D. (2005). ''Advertisement calls of Melanophryniscus dorsalis (Mertens, 1933) and M. montevidensis (Philippi, 1902), two parapatric species from southern Brazil and Uruguay, with comments on morphological variation in the Melanophryniscus stelzneri group (Anura: Bufonidae).'' Salamandra, 41(1/2), 1-18.

Kwet, A., and Miranda, T. (2001). ''Zur Biologie und Taxonomie der Swarzkrote Melanophryniscus atroluteus (Miranda-Ribeiro, 1920).'' Herpetofauna, 23, 19-27.

Langone, J. A. (1994). Ranas y sapos del Uruguay (reconocimientos y aspectos biológicos). Museo Damaso Antonio Larrañaga 5, Serie de Divulgación

Maneyro, R., Forni, F., and Santos, M. (1995). Anfibios del Departamento de Rocha. Serie Divulgación Técnica 1 (PROBIDES), Rocha, Uruguay.

Maneyro, R., and Langone, J. A. (2001). ''Categorización de los anfibios del Uruguay.'' Cuadernos de Herpetología, 15(2), 107-118.

Miranda-Ribeiro, A. (1920). ''Os Brachycephalideos do Museu Paulista (com tres especies novas).'' Revista do Museu Paulista, 12, 305-313.

Núñez, D., Maneyro, R., Langone, J. A. and De Sá, R. O. (2004). ''Distribución geográfica de la fauna de anfibios del Uruguay.'' Smithsonian Herpetological Information Series, 134, 1-34.

Species Account Citation: AmphibiaWeb 2006 Melanophryniscus atroluteus <https://amphibiaweb.org/species/341> University of California, Berkeley, CA, USA. Accessed Nov 8, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 8 Nov 2024.

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