A tiny frog discovered in Brazil has been named the world’s smallest vertebrate. Known as Brachycephalus pulex, this amphibian is so small that it can fit on a Brazilian real coin, which has a diameter of 27 millimeters. The flea toad was first discovered by scientists in 2011 and is smaller than the previous record holder for the world’s smallest vertebrate.
This study highlights how small the flea toad can get compared to other mini frogs, with the smallest specimen in the study being only 6.45 millimeters long. At such small scales, frogs tend to develop unusual anatomical quirks, such as losing toes or having underdeveloped ears.
Despite being known for its small size and being discovered in 2011, only a limited number of flea toad specimens have been collected from its habitat on forested hilltops in southern Bahia, Brazil. In order to verify the species’ maturity and sex, the gonads of the frogs were examined. It was found that only males have vocal slits. Adult male B. pulex frogs are slightly over 7 millimeters long, smaller than the females, making them smaller than the previously known smallest amphibian, the Paedophryne amauensis frog from Papua New Guinea. The findings have led experts to believe that the flea toad may be the smallest extant frog in the world.
The researchers also suggested that there may be even smaller vertebrates yet to be discovered, leading to the possibility of the next record-holder being another small frog or perhaps a parasitic male of a deep-sea anglerfish