While some types of frogs are known to secrete poison from glands in their skin, researchers from Utah State University have reportedly discovered the first two species of the short bodied, tailless amphibians that can actually be considered truly venomous.
As Edmund Brodie, Jr., a professor in the university’s department of biology, and his colleagues report in Thursday’s edition of the journal Current Biology, the species produce powerful toxins and deliver the substances to other creatures through special bony spines on their heads.
The frogs, Corythomantis greeningi and Aparasphenodon brunoi., are native to Brazil but are not actually newly discovered species – they were first identified at least several decades ago, but scientists knew little about them. Brodie explained to redOrbit via email that his team learned the frogs were venomous in the most unfortunate way possible.
His colleague, Carlos Jared of the Instituto Butantan in São Paulo, “was jabbed by spines while collecting Corythomantis in the field,” Brodie said. “Intense, immediate pain radiated up his arm and this condition lasted five hours,” and since he was “many hours” away from medical help, he “toughed it out.” The incident wound up leading to a major discovery. No pain, no gain, right?
Venom is more toxic than that of pit vipers
On the plus side, the study authors explained in a statement, Jared was exposed to the less toxic of the two frogs, as their calculations indicate that the other species, A. brunoi, produced poison secretions powerful enough to kill more than 300,000 mice or roughly 80 humans.
“We compared the frog secretions with those of the deadly Brazilian pit-vipers (Bothrops) by mouse assays,” Brodie told redOrbit. “The secretions of Corythomantis greeningi are twice as toxic, by weight, as Bothrops venom; Aparasphenodon brunoi has secretions 25 times as toxic.”
However, he added, “the fact that these frogs have a stronger venom than pit-vipers does not make them more dangerous. Pit vipers inject a larger quantity of venom than would be transmitted on the tips of the frog head spines. Still, I would not want to test the venoms of Aparasphenodon on myself!”
Neither of the frogs is known to have any natural predators, the authors said – a fact that makes perfect sense in light of their unexpected discovery. They added that their research will help improve the understanding of amphibian biology.
Brodie and Jared also plan to further study both the venom and the glands that produce it, and noted that they intend to study other frog species in other parts of the world, also suspected to be venomous.
(Image credit: Carlos Jared/Butantan Institute)
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