Is The Flea Toad The Smallest Vertebrate In The World?

Is there a lower limit on vertebrate body size? How small can a vertebrate possibly get?

Brazilian flea toad, Brachycephalus pulex. (Credit: Iuri Ribeiro Dias, doi:10.1111/zsc.12654)

A team of herpetologists at the Universidade Estadual de Santa Cruz just reported that a tiny frog found only in a hilltop forest in southern Bahia, Brazil, may be the smallest vertebrate in the world. The scientists came to this extraordinary conclusion after capturing, measuring and releasing 46 individual wild Brazilian flea toads, Brachycephalus pulex, and finding that the adult males averaged just 7.1 millimeters (0.27 inches) in length — almost one millimeter smaller than the world’s next smallest frog species.