Two species of helmeted tree frogs have been found in Brazil and are reported to be venomous. A team of researchers, including Utah State University biologist Edmund "Butch" Brodie, Jr., has come up with the discovery.

The discovery leads to questions regarding the poison dart frog. Brodie said that poisonous term is different from venomous.

According to Brodie, "A poisonous animal has toxins that must be inhaled or ingested by another animal to cause harm. To be described as venomous, the organism must have a delivery mechanism - such as hollow fangs in vipers - to introduce its toxins into other animals".

Brodie has been carrying out a study with colleagues from the Brazil's premier biomedical research center, Butantan Institute and the University of Sao Paulo in the case of the arboreal frogs. The amphibians make use of sharp spines protruding from their skulls to 'head-butt' predators and inject fatal venom. The scientists have reported their findings in an issue of Current Biology and it is the first known information regarding venomous frogs.

Other than Brodie, writers of the paper include Marta Maria Antoniazzi, Pedro Mailho-Fontana, Katia Cristina Barbaro, Vanessa Aparecida Mendes, Miguel Trefaut Rodrigues and lead author Carlos Jared.

Brodie said that it is among 'once in a career' discoveries and is quite strange. The two species are members of a family of amphibians called casque-headed tree frogs. The two species, Corthythomantisgreeningi and Aparasphenodonbrunoi, have flat heads with comparatively long necks and projecting lip-like snouts.