This frog is so small that they call it a flea

This creature is a tiny 6.95 millimeters long, and can fit on the size of your finger. It is smaller than many ant species. Although it looks like a cricket, it is not an insect: it is a very small frog.

The newly discovered animal is one of the smallest known vertebrates on Earth.

“We are talking about the size limits of life on Earth,” said Luis Felipe Toledo, a herpetologist at the University of Campinas in Brazil.

He and his colleagues described the frog in A The study was published Last week in PeerJ, we named it Brachycephalus dacnis after Dacnis Conservation project Through which it was monitored.

Dr. Toledo got his first hint about the tiny frog when a colleague shared several audio recordings of miniature frog species he was collecting in Brazil's Atlantic Forest. As soon as he listened, he knew he was hearing something new.

The Atlantic forests of Brazil are home to many frogs of the genus Brachycephalus, also known as saddleback frogs. Their tendency to hop and hop distances about 30 times their body length has led to the nickname “flea frogs.”

Because Brachycephalus frogs are so small, some of the different species look very similar and cannot be distinguished by sight alone. However, scientists have found that their mating calls are distinct enough that females are attracted to the correct male of their species, and even an inexperienced human listener can hear the differences.

“You know right away that they are different sounds,” said Dr. Toledo, who described the mating call of B. dacnis as shorter, with fewer notes, softer in volume and a playful sound. “People usually think it's a cockroach, not a frog.”

DNA tests provided confirmation that B. dacnis is genetically distinct from other species in its group.

This makes it the seventh scientifically known species of frog, and the second smallest known vertebrate species on the planet. A sample of another was found Brachycephalus frog Slightly smaller, at 6.5mm. These differences are almost imperceptible, according to Dr. Toledo, and are a matter only for the specimens that have been recorded so far – scientists could soon find a specimen of a new B. dacnis species that is also small.

“There are countless numbers of unknown tadpoles,” he says. Mark ShearsCurator of Herpetology at the Natural History Museum of Denmark, who was not involved in this study. He added, “These small species were previously overlooked, due to the difficulty of finding and collecting them.”

Before these discoveries, the world record for the smallest vertebrate was the world's largest Amau frog of New Guinea7 mm long, and Freshwater dwarf goby, 7.9 mm long.

Dr. Toledo's team also performed specialized high-resolution CT scans on the frog to reveal more of the inner workings of how a frog continues to be a frog when it is miniaturized to such an extent.

While frogs usually have four toes on their hands and five on their feet, B. dacnis, like other miniature frogs, has two toes on its hands and three toes on its feet. Parts of his inner ears are also missing.

Many species of Brachycephalus also have fused, ossified bones in the skull, he said Celio Haddad from Sao Paulo State University, who was not involved in the study. But B. dacnis does not: its head resembles that of a normal-sized frog. Dr. Haddad said: “We do not know exactly why this duplication occurs.”

B. dacnis, like all Brachycephalus frogs, also does not undergo the type of amphibian metamorphosis commonly taught in basic biology lessons. They lay only two eggs per reproductive cycle, which hatch into fully formed frogs rather than tadpoles.

While miniaturization makes these frogs vulnerable to small predators, such as ants and spiders, the trade-off seems worth it from an evolutionary perspective, he said. Judy Rowleycurator of amphibians and reptiles at the Australian Museum, who was not involved in the study.

“Miniaturization allows frogs to live in a whole new world that larger frogs cannot enter,” Dr. Rowley said. In addition to providing shelter from predators, these spaces are “full of food that is too small for larger frogs to take advantage of.”

Because Brazil's Atlantic Forest is so heavily deforested, knowing more about these tiny frogs helps their conservation.

“Much of our biodiversity, known and unknown, is small and camouflaged, and it is not surprising that it often goes unnoticed,” Dr Rowley said.