Seven new species of miniature frog, smaller than bumblebees, have been discovered clinging to survival on isolated mountaintops in Brazil.

 

The largest of the new discoveries has a maximum adult length of just 13mm. The frogs, which are among the smallest land vertebrates, have evolved with fewer fingers and toes in order to reduce their size.

 

Miniaturization allows the frogs to emerge from their eggs as fully-formed, albeit tiny, adults. This means they do not go through a tadpole stage and can survive far from standing water. Highly efficient absorption allows them to stay hydrated by soaking water from damp ground through the skin on their bellies.

 

Marcio Pie, a professor at the Universidade Federal do Paraná, led a team of researchers on a five-year exploration of the mountainous cloud forests on the southern Atlantic coast of Brazil. They published their study in the journal PeerJon Thursday.

 

The frogs are all species from the Brachycephalus genus, which are often tiny in size.

 

They live on ‘sky islands’, areas of high forest on mountains surrounded by lower altitude rainforest. The tiny frogs are highly adapted to their conditions and sometimes restricted to a single mountain. There they have evolved in isolation over millennia – much like the unique species on separate Galapagos islands that so fascinated Charles Darwin.

 

The study increases the number of recognized species in the genus by 50% to a total of 21.

 

Luiz Ribeiro, a research associate to the Mater Natura Institute for Environmental Studies, said the new discoveries suggested there were many more to find.

 

 

PHOTO: One of the species of miniaturized frog found in the Brazilian Atlantic forest.

CREDIT: Luiz Fernando Ribeiro, CC BY SA.