Magnifying glass, calipers, teeny tiny tape measure. These are the weapons with which researchers are fighting it out to find the world’s smallest frog.

One team just announced the discovery of the on-average 7.7 millimeter Paedophryne amanuensis, which can sit comfortably on a dime. It was discovered in the moist under-layer of New Guinea’s tropical rainforest. The research was published in the journal Public Library of Science One. [Eric N. Rittmeyer et al., "Ecological Guild Evolution and the Discovery of the World's Smallest Vertebrate"]

The little guy thus ousts another New Guinea frog, which had only claimed the title in December. The newest frog species is also being cited as the world’s smallest vertebrate, although it’s more correctly the smallest free-living vertebrate. A 6.2 millimeter male anglerfish spends its life buried in the body of its mate. 

Finding the little frog was no small achievement. Besides being tiny, the high-pitched mating calls researchers followed sound more insect than amphibian. [Frog calls.]

Tiny vertebrates reveal changes that make miniaturization possible. For instance, some of the digits on the frogs’ feet have disappeared. And their skulls develop differently than those of larger critters.

So we celebrate the world’s smallest frog and free-living vertebrate. Until the next one is discovered.

—Cynthia Graber

[The above text is a transcript of this podcast.]

[Frog audio via Christopher Austin, L.S.U., http://www.museum.lsu.edu/Austin/Lab.html]