A team of researchers has discovered seven new species of tiny, bright colored frogs in mountainous areas of the southern Brazilian Atlantic Rainforest after nearly five years of exploration. The researchers said that the remarkably endemic frogs are restricted to cloud forests -- moist forests with frequent or seasonal low-level cloud cover -- in a few mountaintops.

The highly miniaturized frogs that belong to the genus Brachycephalus are among the smallest terrestrial vertebrates, with an adult measuring less than half-an-inch (one centimeter) in length. Many of the seven Brachycephalus species are brightly colored, suggesting that their skins could have a highly potent neurotoxin, known as tetrodotoxin. The frogs are deemed to be highly vulnerable to extinction because of shifts in the distribution of cloud forest due to climatic changes, the researchers said in a study published in the journal PeerJ on Thursday.

"The high level of microendemism found in some Brachycephalus species might be caused by their [frogs'] climatic tolerance to a narrow set of environmental conditions found only in montane regions,” the researchers said in the study. “This restriction severely limits the chance of discovery of new species, given the difficulty of exploring these inaccessible habitats.”

While the first species was described in 1824, most of the Brachycephalus species have been discovered only over the past 10 years. They remained undiscovered largely due to the difficulty in reaching the remote areas where they live.

“Field work usually involved from two to eight hours of steep trails to get to the sites, and the same time afterwards to get back,” Marcio Pie, a professor at the Universidade Federal do Paraná in Brazil and the study’s lead author, told National Geographic.

According to the researchers, the same factors that led to the frogs’ endemism could also be responsible for their extinction as cloud forests are highly sensitive to climate change. Preservation efforts for the new frog species should not only involve protecting their habitats but also nurturing them in captivity, the researchers said.

“Preserving these areas is crucial not only for conservation, but also to understand how such high levels of biodiversity were generated in the first place,” Pie said.