The Brazilian gold frog (''Brachycephalus didactylus''), also known as Izecksohn's toad or flea-frog, is a very small species of frogs in the family

Brachycephalidae The Brachycephalidae () are a family of frogs confined to eastern and southern Brazil and northern Argentina. The family is composed of two externally quite different genera: the tiny, often (but not always) colourful and plump saddleback toads ...

. It is

endemic Endemism is the state of a species being found only 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 foun ...

to southeastern

Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...

and is known from the central part of the state of

Rio de Janeiro Rio de Janeiro, or simply Rio, is the capital of the Rio de Janeiro (state), state of Rio de Janeiro. It is the List of cities in Brazil by population, second-most-populous city in Brazil (after São Paulo) and the Largest cities in the America ...

and from Serra das Torres in extreme southern

Espírito Santo Espírito Santo (; ) is a state in southeastern Brazil. Its capital is Vitória, and its largest city is Serra. With an extensive coastline, the state hosts some of the country's main ports, and its beaches are significant tourist attracti ...

. All three English names are misleading or potentially confusing. Many species in the genus '' Brachycephalus'' are bright yellow-orange, hence the name "Brazilian gold frog", but ''B. didactylus'' is all brown. "Izecksohn's toad" leads to easy confusion with another species in the genus, '' B. izecksohni'', and both names refer to the herpetologist

Eugênio Izecksohn Eugênio Izecksohn (1932 – June 2013) was a Brazilian people, Brazilian Herpetology, herpetologist.B. hermogenesi'', was described in 1998 and two others, '' B. pulex'' and '' B. sulfuratus'', have been described since then, bringing it to four species of flea-frogs/toads.

Comparison with other small frog species

At in snout–to–

vent Vent or vents may refer to: Science and technology Biology *Vent, the cloaca region of an animal *Vent DNA polymerase, a thermostable DNA polymerase Geology *Hydrothermal vent, a fissure in a planet's surface from which geothermally heated water ...

length, ''B. didactylus'' is one of the smallest frogs in the world. This species and the roughly similar-sized ''

Eleutherodactylus iberia The Monte Iberia eleuth (''Eleutherodactylus iberia''), also known as the Monte Iberia dwarf frog, is a species of eleutherodactylid frog. It is critically endangered and endemic to rainforest in a small part of easternmost Cuba. It is the sma ...

'' from Cuba were once regarded as ''the'' smallest, but several others that are smaller have since been discovered, including the closely related ''B. pulex'' at , ''

Stumpffia ''Stumpffia'' is a genus of microhylid frogs that are endemic to Madagascar. They are mostly brown frogs that typically live among leaf litter. ''S. contumelia'' has a snout–vent length of about , making it one of the world's smallest frogs, ...

contumelia'' from Madagascar at , and ''

Paedophryne amauensis ''Paedophryne amauensis'', also known as the New Guinea Amau frog, is a species of microhylid frog endemic to eastern Papua New Guinea. At in snout-to-vent length, it was once considered the world's smallest known vertebrate. (See also Ecolo ...

'' from New Guinea at . SmallestFrogComparison

References

didactylus Amphibians of the Atlantic Forest Endemic frogs of Brazil Amphibians described in 1971 Taxa named by Eugênio Izecksohn {{Brachycephaloidea-stub