In December 2011, researcher Fred Kraus of the Bishop Museum in Hawaii reported the discovery of two frog species from the mountains of southeastern New Guinea that were smaller than any “already known.” The smaller species—in a genus named Paedophryne—came in at just 8.1 millimeters, making it the world’s smallest non-fish vertebrate, Kraus reported in the journal ZooKeys.
That record didn’t last long. In January 2012, another team found an even smaller frog. Their Paedophryne amauensis frog, also from New Guinea, stretched to just 7.7 millimeters—making it the tiniest known vertebrate. All told, four of the world’s ten smallest frogs now come from the same genus, the researchers noted in PLoS ONE. And eight of the ten live in moist leaf litter.
The discoveries also suggest that “minute frogs are not mere oddities, but represent a previously unrecognized ecological guild,” they write. And “additional miniaturized species,” Kraus says, “no doubt await discovery or description in other poorly surveyed areas of the tropics.”
Kraus F. 2011. At the lower size limit for tetrapods, two new species of the miniaturized frog genus Paedophryne (Anura, Microhylidae). ZooKeys doi:10.3897/zookeys.154.1963.
Rittmeyer E.N. et al. 2012. Ecological guild evolution and the discovery of the world’s smallest vertebrate. PLoS ONE doi:10.1371/journal.pone.0029797.doi:10.1111/j.1365-2745.2011.01910.x.
Photo ©Christopher Austin, Louisiana State University