The tiny PEA-sized frog is the world’s smallest vertebrate

Scientists have discovered a pea-sized frog in a Brazilian forest that may be the world’s smallest vertebrate.

The ‘flea toad’ measures just 7.1 millimeters on average, making it now the smallest in the world – after researchers successfully measured 46 specimens of the tiny amphibian found in the hilltop forest habitat of southern Bahia, Brazil.

The small frog’s upward-facing back blends in with its surroundings in a ‘ground color’ of varying shades of brown, unlike many of the vibrant yellow or orange frogs in similar locations.

Male flea toads were found to be competitively the smallest half of the species, with their female counterparts measuring an average of 8.15 mm in size, or just slightly larger than the previous record holder: the Pedophryne amauensis frog from Papua New Guinea.

To illustrate just how small Brazil’s new record-breaking flea toad really is, the researchers also photographed the tiny creature on a 1 Brazilian real coin. The coin has a diameter of 27 mm and a thickness of 1.95 mm. More than a dozen adult flea toads can fit on a single Real

Biologists have been aware of the existence of the pea-sized flea toad since it was first discovered in the Atlantic rainforest of Bahia in 2011, as first published in Zootaxa.

But this new and more extensive examination of the specimens proved that the team had collected enough samples of adult frogs to draw a firm conclusion about the average size of the species.

“Sizes smaller than average should be confirmed as adults,” the new study reads, “which can be done by direct observation of the gonads.”

The researchers reported their measurements in the peer-reviewed journal Zoologica Scripta last January helped them quickly assess whether the toads were adults by determining “whether they are reproductively mature or not.”

The scientists, including herpetologists from German and Brazilian universities, also examined the frogs for the presence of vocal slits in their throats: a feature that only the males of the species have.

The results were “absolutely clear” according to Mark Scherz, who studies amphibians and reptiles as curator of herpetology at the Natural History Museum of Denmark in Copenhagen.

“These are potentially the smallest extant frogs in the world, which is amazing,” Scherz said. New scientist.

Above is one of the losing competitors of the flea toad, the pumpkin toad or Brachycephalus ephippiumalso posed with another Brazilian 1 Real coin

Above is another losing competitor of the flea toad, the Izecksohns flea toad Brachycephalus didactylusposing on a small mushroom

Scherz, an independent expert not affiliated with the authors of the new study, told the publication that he was impressed by how small the smallest adult flea toads could be.

“It’s 6.45 millimeters long, which is 30 percent smaller than any adult male frog I’ve ever seen,” Scherz said.

“It’s almost a millimeter smaller than the next smallest frog.”

The lengths of adult male flea toads ranged from 6.45 mm to 7.90 mm, the researchers found.

For the adult female flea toads, the range was 7.38 mm to 9.87 mm.

To better illustrate how small Brazil’s new record-breaking flea toad really is, the researchers also photographed the tiny creature on a 1 Brazilian real coin.

The seven-gram coin has a diameter of 27 mm and a thickness of 1.95 mm.

Well over a dozen adult flea toads, formally known as Brachycephalus pulexcould fit on the face of a single genuine coin.

“Identifying the world’s smallest frog was not an easy challenge,” the team admitted in their new report.

For starters, the species just seems to exist two forested hilltops in Brazil’s southern Bahia region.

The study’s lead author, herpetologist Dr. Mirco Solé at Santa Cruz State University in Brazil, had to obtain permission to work on the property from the owners of the private Serra Bonita reserve, Clemira Souza and Vitor Osmar Becker.

They also need extra flea toads or B. pulex samples from the Celio Fernando Baptista Haddad Amphibians collection.

Solé and his co-authors noted that it was remarkable that even in these tiny, pea-sized frogs, males were smaller than females – a form of “sexual dimorphism” that applies to 90 percent of all frog and toad species. ‘anura’ amphibians.

The researchers were also impressed by its smallness B. pulex meant that it actually had no hard ‘bony elements’, apart from a very hard and thick, or ‘hyperossified’, skull and spine.

But, as Solé and his team suggested in their paper, the flea toad may not sit on its crown for long, wondering, “Has the lower limit of vertebrate numbers really been reached?”