A Brazilian scientist has made a painful discovery of two species of venomous frogs, capable of injecting toxic venom into its predators. Though there are a number of “poisonous” frogs with toxins in the skin, this is the first time “venomous” frogs have been discovered.
Carlos Jared, a researcher at Instituto Butantan in Sao Paulo was head-butted by one of the frogs, jabbing the spines into his hand when he was collecting frogs in a forest Goytacazes National Reserve in southeastern Brazil. According to the study published in the journal Current Biology by Jared and co-authors, the pain radiated up his arm, and lasted for about five hours.
“It is likely that venomous amphibians are more toxic and common than previously assumed,” said researchers.
The two species — Aparasphenodon brunoi and Corythomantis greeningi are not only toxic, but venomous also as the poison is secreted on its skin and head. They have an effective delivery mechanism as they have skulls with bony spines and toxic-producing skin glands. The toxin profiles of the frogs revealed that they do not absorb toxins from noxious insects like the poison dart frogs of Central and South America.
Study co-author Edmund Brodie, Jr., a herpetologist at Utah State University in Logan, said in a statement:
“The strength of toxicity of the skin secretions is remarkable, and to say we were surprised by that is an understatement. Amphibians have a wide array of skin toxins that have been well-studied, but this sort of mechanism — transmitting the toxin as a venom — has not been found before. It moves the study of amphibian defenses to a new level.”
Researchers said that these frogs release the toxins in the same way by releasing a “sticky secretion” and flex their head, jabbing and rubbing spines into the hand. Their ability is also maximized by moving their heads, which other frogs can’t. Researchers believe that the spines are not as effective as delivering venom using fangs like the pit viper. There are no known predators of these frog species.
Researchers mentioned that these are not the only frogs with spines on their head, and they have not tested the secretions from other spiny-headed frogs. This has prompted the team to study other frog species around the world, to ascertain if they are venomous or not.