A new rain frog species has been described from Amazonian Peru and the Amazonian foothills of the Andes. The frog, given the name Pristimantis pluvialis, was found by researchers from Southern Illinois University Carbondale, the University of Michigan, and the National University of San Antonio Abad of Cusco in Peru. The discovery is published in the open access journal ZooKeys.

Several individuals of P. pluvialis were found during nocturnal surveys near Manu National Park, a region recognized as having the highest diversity of reptiles and amphibians of any protected area.

The species has also been collected within the private conservation area Bosque Nublado, owned by the Peruvian NGO Perú Verde, and within the Huachiperi Haramba Queros Conservation Concession, the first such type of concession granted to a native community in Peru.

The new species is likely found within the park as well, bringing the number of known amphibian species in this area to 156. Similarly to other species within its genus, which is among the largest vertebrate genera, the new rain frog exhibits direct development. This means that it is capable of undergoing its entire life cycle without a free-living tadpole stage.

It can be distinguished from other members of its genus by call, skin texture, and the presence of a rostral papilla. It was given the name "pluvialis," translatable to "rainy" from Latin, to denote the incredibly rain-soaked habitat it lives in (>8 meters of rain yearly), and because it was found calling only after heavy rains.

Unfortunately, when a fungal disease, known as the amphibian chytrid fungus, arrived in the area back in the early 2000s, many frog species in and around the region began to decline. Out of the studied ten individuals of the presently described new species, four were found to be infected. However, the impact of the disease on these particular rain frogs is still unknown, and their numbers do not seem to have decreased.

"This discovery highlights the need for increased study throughout the tropics, for example Manu NP and its surrounding areas have been well studied, but despite these efforts, new species are being continuously discovered," points out first author Alex Shepack, a PhD student in the laboratory of co-author Dr Alessandro Catenazzi at Southern Illinois University.