Frogs probably don’t normally elicit an *aaaaw* response, but there is just something about tiny things that make them utterly adorable.
The weeny species pictured above, plus six more, were all discovered recently following an arduous five year hunt in the Brazilian Atlantic Rainforest. With some adults not exceeding a puny 1 centimeter in length, you can easily envisage how tricky they were to spot, even with the striking colors sported by some.
The micro-amphibians all belong to a group, or genus, called Brachycephalus, members of which are up there with the world’s tiniest known terrestrial vertebrates. Their thumbnail-size is not without consequences and has led to various changes in body structure, such as a loss of toes and fingers. Although some Brachycephalus species are rather drab in appearance, blending in with the brown of tree trunks and dead leaves, several display conspicuous coloration patterns that are associated with the presence of a highly potent neurotoxin in the skin.
Brachycephalus olivaceus. Credit: Luiz Fernando Ribeiro, CC BY SA
Since Brachycephalus was first described in 1824, twenty-one nominal species have been added to the group, but more than half of the currently recognized species have been discovered over the past 15 years. This suggests that the diversity of this unique group could be underappreciated, which is why researchers, headed by Marcio Pie, headed to their rainforest home in Brazil to see what they could find, and it certainly proved a fruitful endeavor.
As described in PeerJ, the frogs were discovered following extensive fieldwork in montane areas of the southern portion of the Atlantic Rainforest across the states of Paraná and Santa Catarina. After specimens were collected, the scientists used differences in the frogs’ morphology, in particular their coloration and the level of roughness in different parts of the body, in order to assign them. But since the original descriptions, DNA sequencing data has confirmed their distinctiveness, Pie told IFLScience.
The frogs ranged in color from brown to bright yellow and orange, but one in particular stood out as truly unique. This species, B. mariaeterezae, has a light blue stripe along its back that had not been previously observed in any member of this genus.
B. mariaeterezae. Credit: Luiz Fernando Ribeiro, CC BY SA
The majority of species within the Brachycephalus group so far discovered have only been found in very small ranges, at the scale of just a few neighboring mountain tops, said Pie. This highly endemic nature is the result of adaptation to their cloud forest habitat, which also limits their spread to other environments and thus increases the rate of new species formation.
But this endemism also comes at a cost, as only being found in one spot increases the likelihood of extinction following environmental alterations, for example from deforestation or climate change. That’s why, Pie says, it is urgent to document the existence of such species and to think about management plans to ensure their long-term survival.
Although there isn’t enough data to assign the new frogs a conservation status, Pie tells IFLScience that his team is in contact with state and federal environmental protection agencies to negotiate the creation of reserves in the region, which he calls an “evolutionary cradle of species.”
B. fuscolineatus. Credit: Luiz Fernando Ribeiro, CC BY SA