Researchers have discovered two species of what may be the world’s smallest frog species. As described in the journal PloS ONE, these new species of mini, terrestrial frogs were found on the island of New Guinea, and represent not only the smallest known frog but possibly also the smallest known vertebrate species (animal with a backbone). Both new species are members of the recently described genus Paedophryne, the four species of which are among the ten smallest known frog species. They attain an average body size of only 7.7 mm (range 7.0–8.0 mm), less than the size of an M&M.
The researchers believe that the frogs have evolved their teeny size in a unique ecological niche: the leaf litter of tropical forests that remains moist year round. The frogs eat even tinier creatures (mites etc) that most other frogs don’t exploit. They are well camouflaged among leaves on the forest floor, and have evolved calls resembling those of insects.
According to the researchers, other places in the world that also feature dense, moist leaf litter tend to possess such small frog species, indicating that amphibians are well placed to occupy this ecological niche.
Before the Paedophrynes were found, the title of “world’s smallest frog” was bestowed on the Brazilian gold frog (Brachycephalus didactylus) and its slightly larger Cuban relative, the Monte Iberia Eleuth (Eleutherodactylus iberia). They both measure less than 1cm long.
For more information:
Rittmeyer EN , Allison A , Gründler MC , Thompson DK , Austin CC , 2012 Ecological Guild Evolution and the Discovery of the World’s Smallest Vertebrate. PLoS ONE