In 1817, a German biologist named Johann Baptist von Spix set out for Brazil, together with his colleague, a German botanist named Carl Friedrich Philipp von Martius, and a group of Austrian researchers. After spending some time in Rio de Janeiro with their Austrian colleagues, Spix and Martius set off on their own, exploring the vast wilderness of the Caatinga scrubland, the Amazon jungle, and the Atlantic forest.

In addition to cataloguing and describing all the plants and animals they encountered, they also took notes on the activities and lifestyles of the indigenous people they met, they looked for fossils, and they examined a meteorite. In 1820, the duo returned to Munich, and their specimens would form the founding collections of the city’s natural history museum. While Spix is perhaps most famously associated with a macaw that now bears his name, he also first formally described a curious group of frogs found in the Atlantic forests, members of a genus called Brachycephalus.

These frogs are some of the smallest vertebrates known to science, with adults rarely growing larger than a single centimeter in length. Because they’re so small, their bodies have evolved to be slightly different than other frogs; some have fewer fingers and toes, for example. Most of them are brightly colored, betraying their toxic nature.

While the first tiny Brachycephalus was described by Spix in the 1820s, most other species within the genus haven’t been discovered, catalogued, or described until the last few decades. That’s because they live in remote cloud forests, small forested areas near the tops of mountains shrouded in thick blankets of suspended water droplets. Because the frogs rely on that sort of habitat, they can’t move from mountaintop to mountaintop by crossing the valleys between them. So each species is known from just one mountaintop, or occasionally from a handful of adjacent ones. In effect, they live on individual “sky islands.”

Until this week, researchers had counted 21 species of Brachycephalus, but today a group of Brazilian researchers published the descriptions of a whopping seven more, the results of five long years of fieldwork.

While some of the new species were given straightforward names (Brachycephalus auroguttatus was named for its gold colored spots; aurum is Latin for gold and gutta means spots or drops), others were named with a variety of honors in mind. B. mariaeterezae, for example, was named for Maria Tereza Jorge Padua, a well-known Brazilian conservation advocate. Another, B. boticario, was named for the Fundação Grupo Boticário de Proteção à Natureza, a Brazilian conservation organization that partially funded the fieldwork in this study.

Since they found so many new species, the researchers suspect that many more are waiting to be discovered, that this genus of colorful amphibians is more diverse than was previously thought. Unfortunately, whatever species are left unknown to science – along with the newly described ones – might already be dwindling because of human activities.

“Although little is known about the natural history of the new species described in the present study, assessments over the course of our fieldwork raise concern about their conservation status,” write the researchers. Brazilian cloud forests, already so limited in extent, are increasingly becoming disturbed – often illegally – due to deforestation for pine tree plantations and for the cattle industry. Even in cases where cattle graze at low densities, their foraging compacts and tramples the leaf litter on the forest’s floor, which is prime real estate for these tiny frogs.

In addition, climate change is forcing the cloud-covered forests higher and higher up the mountains’ slopes, taking the frogs with them. Eventually, the forests will have nowhere to go and the frogs’ critical habitat will disappear.

To address these conservation concerns, the researchers call on state environmental agencies to more strictly regulate the illegal logging industry as well as cattle farmers, and to include the new species in Brazil’s reptile and amphibian conservation plans. In addition, the researchers warn that captive assurance populations might need to be created if climate change further stresses the frogs’ ecosystems. – Jason G. Goldman | 05 June 2015

Source: Robeiro, L F et. al. (2015) Seven new microendemic species of Brachycephalus (Anura: Brachycephalidae) from southern Brazil. PeerJ 3:e1011. DOI: 10.7717/peerj.1011.

Header image: Luiz Fernando Ribeiro, CC-BY-SA.