In a small region of the mountainous forests in Brazil, the peaks meet the clouds and humidity fills the air.
As the leaves fall, they make thick layers of soft material on the forest floor. It's the perfect place for a tiny amphibian to make a home -- and where a new species has been discovered.
In two field expeditions in December 2021 and March 2022, researchers carefully searched through the fallen leaves of Estação Ecológica de Bananal, a section of the Serra da Bocaina Mountain range, according to a study published Sept. 9 in the peer-reviewed journal Zootaxa.
"We actively searched the area with careful removal and analysis of the leaf litter at the site, dedicating seven hours for day search and two hours for night search, totalizing 40 hours of effort/person," researchers said.
Their work was not in vain. As they searched, six tiny frogs were found hiding in the leaves.
Less than a centimeter long, these "extremely small" frogs are called flea-toads, or "pumpkin toadlets," according to the study.
They are so small they can fit on the tip of a finger.
The frogs are "slender" in the body but their heads are as wide as they are long, according to the study.
They are generally brown in color, with "a few golden spots" scattered on their backs, researchers said. They have a golden stripe that stretches from the tip of the snout to their sides, and the tops of their arms and legs have dark brown stripes.
All of the frogs were found sheltering, sometimes under fallen trees, but they had different approaches to dealing with potentially being captured, researchers said.
"The specimens displayed different defensive behaviors upon our approach: motionless, crouching down posture, or fleeing by jumping away," according to the study. "... Being motionless or in a crouching posture, in addition to its cryptic coloration, provides individuals an advantage against visually oriented predators. Fleeing by jumping, besides avoiding subjugation, could be especially successful for the flea-toads, which could jump several times its body length, falling in the matching background leaf litter far from the predator."
The frogs were primarily active during the day, and chose to come out more on moist days, researchers said. The frogs are particularly susceptible to drying out, known as desiccation, because of their incredibly small size.
"For this reason, the leaf litter environment is important, because it provides not only shelter but also the moisture that protects the frogs from desiccation even in the driest or coldest conditions," according to the study.
"It is worth noting that this species is micro-endemic -- only known to a single spot in the Atlantic rainforest and we still don't know much about the species, not even its vocalization was recorded," study author L. Felipe Toledo told McClatchy News in an email. "But, we have some data on diet and anatomy -- in the paper -- which is rare for these tiny species."
Flea-toads are known for their "cryptic or conspicuous coloration" and are found at elevations more than 6,500 feet. They have a wide geographical range for a genus, but most of the individual species have extremely small species-level ranges, according to the study.
The species was named Brachycephalus nanicus, the genus name referring to the frogs called flea-toads, and the species name coming from the Latin word meaning "those with reduced size," according to the study.
Bananal is in the state of São Paulo in southeastern Brazil.
The research team includes Toledo, Ivan Nunes, Mariana L. Lyra, Thaynara M. Machado, Andres Santiago Carrasco-Medina, Felipe Silva de Andrade, Isabelle Aquemi Haga, Lucas M. Botelho, Mariana Pedrozo, Isabel G. Velasco, Fernando De Castro Jacinavicius, Jaimi A. Gray, David C. Blackburn, Tiana Kohlsdorf and Edélcio Muscat.