7 Tiny New Frogs Discovered
In the “cloud forests” of south-east Brazil, cool forest-covered mountains peak up over the hot jungle below. The mountain peaks are like ecological islands, separated from each other by the very different environment of the valleys between.
In these cloud forests live a genus of tiny frogs known as Brachycephalus. Previously 21 species of Brachycephalus were identified, but a recent 5 year expedition has uncovered 7 new species, raising the total to 28.
The frogs, in addition to being very small, share other traits, such as being brightly colored and highly toxic. Their skin is covered with a powerful neurotoxin called tetrodotoxin, their primary defense.
Marcio Pie of Federal University of Parana and his team spent five years searching for the frogs. They report that they would typically hear the frogs first, but they would go silent as they approached. The researchers would then have to poke through the dried leaves looking for the small frogs.
Tiny frogs are among the smallest vertebrates, and the smallest vertebrate known belongs to a distinct but related genus of frogs known as Paedophryne, found on the island of New Guinea.
The 28 species of Brachycephalus are good examples of evolutionary speciation through isolation. The cloud forests, acting like ecological islands, have allowed Brachycephalus populations to evolve into their own species.