In Brazil, scientists have discovered a new frog that may be the world’s smallest vertebrate. Known as the flea toad, or Brachycephalus pulex, it was found perched on a Brazilian real coin with a diameter of 27 millimeters. Although it was discovered in 2011, only a few specimens have been collected from its habitat on forested hilltops in southern Bahia.
To verify the species’ maturity and sex, the gonads of the frogs were examined. The results showed that only males have vocal slits, making them slightly over 7 millimeters long, smaller than females. This makes them smaller than the previously known smallest amphibian, the Paedophryne amauensis frog from Papua New Guinea.
The study also revealed how small flea toads 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 like losing toes or having underdeveloped ears.
Researchers suggest 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. Despite its small size and limited number of specimens collected, researchers believe that flea toad may hold secrets about how small creatures can survive and thrive in extreme environments.