Its call was “pretty generic" as far as frogs go, but it was intriguing enough that he followed the sound straight to a tree in Brazil's Floresta Nacional de Pau-Rosa, a protected area in the state of Amazonas (map).  

The mystery amphibian was too high to simply reach up and grab, so Peloso had to carefully stand up in his fishing boat and pull the tree branches down, revealing a bright-yellow frog with orange feet. 

“I had never seen anything like it before,” said Peloso, a herpetologist who divides his time between New York City's American Museum of Natural History and Brazil's Museu Paraense Emílio Goeldi. 

Peloso named the species Dendropsophus mapinguari, after a mythical rain forest beast called the mapinguari. The legend of the tall, furry monster with giant claws and a second mouth in its belly likely originates from sightings of the extinct giant ground sloth, which once roamed South America. 

The name doesn't suggest the 22-millimeter-long frog is scary—instead, Peloso wanted to honor the culture of this region in north-central Brazil. (Also see "Seven New Mini-Frogs Found—Among