In Brazil, a tiny frog was discovered that could be the world’s smallest vertebrate. Brachycephalus pulex, also known as the flea toad, has been seen perched on a Brazilian real coin with a diameter of 27 millimeters. This amphibian was first described by scientists in 2011 and is smaller than the previous record holder for the world’s smallest vertebrate.
The study found that only males have vocal slits, with adult male B. pulex frogs being slightly over 7 millimeters long, making them smaller than females. The flea toad is now believed to be the smallest extant frog in the world, with the smallest specimen in the study being only 6.45 millimeters long.
At such small scales, these frogs tend to develop unusual anatomical quirks, such as losing toes or having underdeveloped ears. 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.