Brazilian flea toad stands out as the world’s smallest vertebrate

A tiny Brazilian frog concerning the dimension of a pea could threaten the present record-holder for the world’s smallest vertebrate.

The flea toad Brachycephalus pulex (really a frog species) was first described by scientists in 2011. Shortly after, Mirco Solé on the State University of Santa Cruz in Brazil questioned if the species may very well be the smallest amphibian but found. But solely a handful of specimens had been collected from the frogs’ solely recognized habitat on two forested hilltops in southern Bahia, Brazil. And their gonads hadn’t been examined, which is critical to substantiate if they’re adults.

Solé and his colleagues measured the physique lengths of 46 flea toads, verifying the frogs’ maturity and intercourse by inspecting their gonads and checking for the presence of vocal slits of their throats, one thing solely males have.

Adult B. pulex males common a contact over 7 millimetres lengthy, barely smaller than the females. This makes them smaller than the males of Paedophryne amauensis, a frog from Papua New Guinea that was, till now, thought of each the smallest amphibian and smallest vertebrate.

“It’s completely clear,” says Mark Scherz on the Natural History Museum of Denmark in Copenhagen. “These actually are doubtlessly the smallest extant frogs on the planet, which is astonishing.”

It isn’t simply the typical dimension that’s surprising, however how small these flea toads can get in contrast with different mini frogs – illustrated by the smallest specimen within the research. “It’s 6.45 millimetres [long], which is 30 per cent smaller than any grownup male frog I’ve ever seen,” says Scherz. “It’s virtually one millimetre smaller than the following smallest frog.”

At such small scales, frogs develop unusual anatomical quirks, resembling shedding toes or having such underdeveloped ears that they’ll’t hear their very own suitors’ songs. Some species can hardly leap as a result of their stability organs are so wee.

Yet there may even be smaller vertebrates nonetheless undiscovered, says Solé. Perhaps the following record-holder is one other teensy frog, or perhaps a parasitic male of a deep-sea anglerfish.