The smallest frogs in the world have been found in New Guinea. These tiny frogs, just one-third of an inch in length and well camouflaged in dark brown, could have easily gone unnoticed in the leaf litter and moss of the rainforest floor. But Fred Kraus, a zoologist at the Bishop Museum in Honolulu spotted these diminutive creatures while conducting field research in the rainforests of southeastern New Guinea. He announced his results in the online journal ZooKeys on December 12, 2012.
Here’s a close-to-actual-size image of one of the frogs, Paedophryne dekot, shown at a scale of about 8 millimeters in length. Image credit: Fred Kraus, Bishop Museum.
Actually, Kraus had found two different frog species: Paedophryne dekot and Paedophryne verrucosa. Ranging just 8 to 9 millimeters in length, they are also the smallest known tetrapods (non-fish vertebrates). With such tiny digits, these frogs are not good climbers; they live among leaf litter and moss on the rainforest floor, feeding on small invertebrates. Females, slightly larger than the males, carry only two eggs at a time.
In 2002, not far from the locations of his new discoveries, Kraus had also discovered two other frog species of the genus Paedophryne. Those frogs were a bit larger, about 10 to 11 millimeters in length.
In a press release, Kraus commented,
Miniaturization occurs in many frog genera around the world but New Guinea seems particularly well represented, with species in seven genera exhibiting the phenomenon. Although most frog genera have only a few diminutive representatives mixed among larger relatives, Paedophryne is unique in that all species are minute.
The four Paedophryne frog species — the two recently discovered species that are the smallest frogs in the world, and the two slightly larger species found in 2002 — are the smallest known tetrapods. In his recently published paper announcing the discovery of Paedophryne dekot and Paedophryne verrucosa, Kraus commented that there are likely more miniature frog species awaiting discovery in the tropics.