Biologists in Brazil have discovered the first venomous frogs ever known. Unfortunately, they discovered this in the most painful way. Carlos Jared, who works with the Butantan Institute in Sao Paulo, Brazil, was doing field work in the Goytacazes National Forest when he decided to pick up a small and lumpy green and spotted frog known as the Brazilian hylid frog or the Corythomantis species. But while he was holding it, the little creature raked its spikes onto Jared's skin and made a cut on his hand.

The scientist instinctively dropped the frog and then writhed in pain. His co-study author, Edmund Brodie, Jr., described this as an "intense pain, radiating up the arm, lasting for five hours," according to NBC News.

"We have not experienced the effect of the venom of the most toxic species, and hope we do not," Brodie said.

Some frog species are known to be poisonous, but it's only now that scientists have been able to determine a venomous species. There is a difference between poisonous and venomous creature, as explained in this graphic cartoon from Bird and Moon. Poisonous creatures can only secret the toxins, however, venomous creatures inject them and cause more harm.

The Corythomantis delivers the toxins through the sharp ridges found around its face where the venom glands are located. The researchers said the toxin is "twice as potent as that of a deadly pit viper."

The scientists also found a second type of venomous Brazilian hylid frog, the Aparasphenodon brunoi, with brown stripes, which is said to be 25 times more potent than a pit viper. Roughly, one gram of the venom can kill 80 people.

The researchers said that both frog species are not even remotely related, but there could be more venomous frogs to be discovered.

The biologists' findings were published in Current Biology.