''Frostius'' – known as Frost's toads – is a small genus of

true toads A true toad is any member of the family Bufonidae, in the order Anura (frogs and toads). This is the only family of anurans in which all members are known as toads, although some may be called frogs (such as harlequin frogs). The bufonids now ...

consisting of only two species

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

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 ...

. The genus was proposed by David C. Cannatella in 1986 based on an analysis of a species previously classified as ''

Atelopus ''Atelopus'' is a large genus of Bufonidae, commonly known as harlequin frogs or toads, from Central America, Central and South America, ranging as far north as Costa Rica and as far south as Bolivia. ''Atelopus'' species are small, generally br ...

''. Various morphological and life-history information first suggested that it is

sister taxon In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and t ...

to ''Atelopus'' or ''Atelopus'' + ''

Osornophryne ''Osornophryne'' (plump toads) is a genus of true toads endemic to the Cordillera Central in Colombia and central Andes in Ecuador Ecuador ( ; ; Quechua: ''Ikwayur''; Shuar: ''Ecuador'' or ''Ekuatur''), officially the Republic of Ecuado ...

'', but later molecular evidence suggests that it is sister taxon to ''

Oreophrynella ''Oreophrynella'', commonly known as bush toads, is a genus of true toads native to the tepuis of southern Venezuela and adjacent Guyana. The distribution of some species is restricted to a couple of tepuis or even a single tepui, as in the case ...

''. It was named for

Darrel Frost Darrel Richmond Frost (born 1951) is an American herpetologist and systematist. He was previously head curator of herpetology at the American Museum of Natural History, as well as president of both the Society for the Study of Amphibians and Repti ...

in recognition of his work on anuran

systematics Biological systematics is the study of the diversification of living forms, both past and present, and the relationships among living things through time. Relationships are visualized as evolutionary trees (synonyms: cladograms, phylogenetic tre ...

Species

There are only two species in this genus:

References

Amphibians of South America Endemic fauna of Brazil Amphibian genera Taxa named by David C. Cannatella {{Bufonidae-stub