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LOGAN — The first known venomous frogs in the world were discovered with help from a biologist at Utah State University.
While the two helmeted tree frog species were previously known to scientists, no one knew that they — or any other frog species, for that matter — were venomous. In order to be considered venomous, instead of poisonous like poison dart frogs, animals need to be able to inject their toxins directly into others.
In the case of the Corthythomantis greeningi and Aparasphenodon brunoi species, frogs use spines in their heads to introduce toxins into predators. In contrast, poisonous frogs need to be consumed in order for a predator to be affected by their toxin.
"It takes frog adaptations to predators to a whole new, unforeseen level," USU biologist Edmund "Butch" Brodie said of the finding.
Brodie was part of the team that researched the discovery, which was reported in Current Biology Thursday. The investigation into the frogs was launched after fellow researcher Carlos Jared was jabbed in the hand by a C. greeningi specimen while collecting frogs in Brazil.
An intense pain immediately surged through Jared's arm and remained for about five hours, according to Brodie. He said because Jared was out in the field, he didn't have access to any medical help. Instead, Jared lay down and waited out the pain, assuming it wouldn't kill him because up until that point no one knew the frogs were dangerous to handle.
"Those are the eureka moments in science, where one experiences or sees something that no one else had ever imagined might be the case," Brodie said. "That's really what we have here. Carlos grabbing the frog by the head led to this study."
Researchers are still analyzing the frog's venom, but said it is made of enzymes similar to those found in other venomous animals, like snakes, scorpions and even fish.
Another surprising finding for researchers was just exactly how very toxic these venoms are, according to Brodie. The A. brunoi's venom was determined to be 25 times stronger than the venom found in Brazil's deadly pit vipers, while the C. greeningi has venom that is two times more toxic than the pit viper.
"Now, one doesn't get the same amount of toxin from a frog's spine as you would get by being bitten by a pit viper, but there is enough there to be dangerous," Brodie said. "We are exceedingly careful now handling these frogs."
C. greeningi and A. brunoi are the only known venomous frogs for now, but it might not remain that way for long. Brodie said his team, which includes researchers from Brazil's Instituto Butantan and the University of Sao Paulo, is currently studying several other frog species that they suspect are also venomous.
