Two Brazilian frog species use sharp spines protruding from around their noses and mouths to deliver toxins in their skin to predators — the first evidence of a venomous frog.

Credit: Carlos Jared/Butantan Inst.

Most frogs produce toxins in their skin but have no way of deliberately passing them on to predators. Edmund Brodie at Utah State University in Logan and his team discovered this toxin delivery when they were collecting specimens of two tree-frog species (Corythomantis greeningi and Aparasphenodon brunoi) and restraining them in their hands. C. greeningi (skull, pictured) jabbed its spiny head into the offending hand and released toxins from its skin glands, causing intense pain in the arm for several hours. When tested in mice, the venom from both frog species caused swelling and was deadly at high concentrations.

There could be more venomous amphibians than thought, the authors say.

Curr. Biol. (2015)