''Melanophryniscus atroluteus'' is a species of

toad Toad is a common name for certain frogs, especially of the family Bufonidae, that are characterized by dry, leathery skin, short legs, and large bumps covering the parotoid glands. A distinction between frogs and toads is not made in scientif ...

in the family

Bufonidae {{Cat main, Toad This category contains both species commonly called toads, and the true toads from the family Bufonidae {{Cat main, Toad This category contains both species commonly called toads, and the true toads from the family Bufonidae {{Cat m ...

. It is found in northeastern

Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...

Uruguay Uruguay (; ), officially the Oriental Republic of Uruguay ( es, República Oriental del Uruguay), is a country in South America. It shares borders with Argentina to its west and southwest and Brazil to its north and northeast; while bordering ...

, southern

Paraguay Paraguay (; ), officially the Republic of Paraguay ( es, República del Paraguay, links=no; gn, Tavakuairetã Paraguái, links=si), is a landlocked country in South America. It is bordered by Argentina to the south and southwest, Brazil to th ...

, and southern

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

(

Rio Grande do Sul Rio Grande do Sul (, , ; "Great River of the South") is a Federative units of Brazil, state in the South Region, Brazil, southern region of Brazil. It is the Federative_units_of_Brazil#List, fifth-most-populous state and the List of Brazilian st ...

, presumably also Santa Catarina). While in the past it was considered a

subspecies In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. Not all species ...

of '' Melanophryniscus stelzneri'', it might rather be conspecific with ''

Melanophryniscus montevidensis ''Melanophryniscus montevidensis'', also called Darwin's toad, is a species of toad in the family Bufonidae and the genus Melanophryniscus found in Brazil and Uruguay. Like other amphibians in its genus, its bright colors, defensive behavior, a ...

''. Common name Uruguay redbelly toad (also spelled Uruguay red belly toad) has been coined for it.

Description

Males can reach and females in snout–vent length, although reported lengths are commonly slightly smaller. Skin is strongly granular. The dorsum is uniformly black, without blotches, while the belly is black and has red and/or yellow blotches. The throat is dark. Webbing is poorly developed.

Behavior

When threatened, this species exhibits the

Unkenreflex Unkenreflex – interchangeably referred to as unken reflex (''Unke'' is the German word for the genus of fire-bellied toads) – is a defensive posture adopted by several branches of the amphibian class – including salamanders, toads, and cert ...

behavior.

Habitat and conservation

''Melanophryniscus atroluteus'' occurs in grasslands at elevations up to . Breeding is explosive and takes place in temporary pools and agricultural ditches. In parts of its range (Argentina and Uruguay,), ''M. atroluteus'' is abundant during the breeding, but it is rare or uncommon elsewhere. It can occur in substantially disturbed habitats, but not in areas with intensive cattle activities. It is threatened by pine and ''Eucalyptus'' plantations and by drainage of wetlands. Pet trade might also become a threat. It does not appear to occur in any larger protected areas.

References

{{Taxonbar, from=Q1941834 atroluteus Amphibians of Argentina Frogs of Brazil Amphibians of Paraguay Amphibians of Uruguay Taxa named by Alípio de Miranda-Ribeiro Amphibians described in 1920 Taxonomy articles created by Polbot