These newly discovered mini-frogs are so small they barely fit on your fingernail – but, they do come in some flashy colors!

Brachycephalus (Anura: Brachycephalidae) is a remarkable genus of miniaturized frogs that call the Brazilian Atlantic Rainforest home. The first Brachycephalus species was found in 1824, but most of the species have been discovered over the past 15 years.

Brachycephalus leopardus is dark yellow with black spots – looks like its hitting the gym! IMAGE: MARCIO R. PIE, CC BY SA

A new species of Brachycephalus from Brazil IMAGE: LUIZ FERNANDO RIBEIRO, CC BY SA

The seven new species live on seven distinct mountaintops in south eastern Brazil. Their habitats are known as ‘cloud forests.’ Each species is cut off from one another due to dips and valleys with varying climates that act as environmental barriers.

Brachycephalus are a group of frogs known for their bright colors and miniscule size – some are the smallest terrestrial vertebrates on record (less than 1cm). Their tiny frog anatomy has shrunk to their size, but one thing has changed. These amphibians typically have three toes and two fingers, instead of the five toes and four fingers found in most frogs.

Their skin is what sets them apart. They vary in color and texture; some are rough and bumpy, while others are quite smooth. Their bright colors alert predators to the poisonous toxins in their skin. Those with brighter colors often reflect higher levels of the deadly chemical tetrodotoxin.

The severe isolation experienced by these frogs has produced 21 known species of Brachycephalus – and a new study has pushed that count to 28.

Marcio Pie, a professor at the Universidade Federal do Paraná in Brazil, led researchers into the remote misty rainforest in search of these tiny critters. Following extensive fieldwork, treacherous hikes, and hours of sifting through dirt and leaves, they found a surprising seven new species of Brachycephalus!

Marcio Pie’s findings were published June 4 in the journal PeerJ.