Seven new species of miniature frogs, small enough to sit on your fingertip, have been discovered in Brazil's high-altitude cloud forests. 

The tiny frogs are less than 1cm (0.4 inches) long! Image: Luiz Ribiero

Because these tiny amphibians (genus Bracycephalus) are extremely sensitive to their environment, even the slightest temperature change is a threat to their survival – and that restricts each species to a very particular elevation along the towering cliff faces. "Much of the genus is highly endemic to cloud forests, being found only on one or a few mountaintops," says Luiz F Ribiero, who published the findings in a study this week. “But exploring these inaccessible habitats makes it very difficult to find them.”

In their search for the frogs, the team would often hear the elusive amphibians long before they could see them, and imagining what they'd look like became a favourite pastime in the field. Even the slightest vibration in the leaf litter could render the frogs silent for extended periods of time. "It takes a lot of practice and sometimes it's very frustrating to go up the mountain for many hours and come back empty-handed," adds co-author of the new study, Marcio Pie. 

Little is known about the life history of these miniature frogs, but assessments over the course of the team's fieldwork raised concern about their conservation. “Cloud forests in southern Brazil have experienced disturbances from a variety of sources, particularly from (often illegal) deforestation for pine tree plantations and extensive cattle ranching," they explain. Even minimal cattle foraging can severely trample the leaf litter that the frogs rely on to survive.  

Ensuring the future survival of these remarkable creatures will require extensive efforts to protect their habitat, but in the meantime, the work of discovery goes on. The team has already come across four more species, and the details of those finds are soon to be published. "We are very confident that we're going to find even more," says Pie.

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Characterised by a thin blue line along its back (masked here by the camera's flash) Brachycephalus mariaeterezae is also distinguished from the other frogs by brown spots on its sides and belly. Image: Luiz RIbiero
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It's easy to see where Brachycephalus olivaceus gets its name! The dark green colouration reminded the team of the salty snack. Image: Luiz Ribiero
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Talk about a stunner. Brachycephalus auroguttatus' signature look is a vibrant, yellow-brown ombre.
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Brachycephalus verrucosus is one of the bumpiest of the tiny frogs. Its green is similar to that of olivaceus, but the fiery belly sets it apart. Image: Luiz Ribiero
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Brachycephalus fuscolineatus is definitely rocking the stripes, but if you look closely, you'll also see irregular black spots along the legs. Image: Luiz Ribiero
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Here we see Brachycephalus leopardus (named for its spots) during amplexus. Meaning "embrace" in Latin, amplexus is a type of mating behaviour exhibited by externally fertilising species like frogs. The male will grab the female with his front legs and fertilise the eggs as they are released. Image: Luiz Ribiero
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Last but not least is Brachycephalus boticario – the frog with the brown backside. Image: Luiz Ribiero

Top header image: Jodi/Flickr