USU Professor Helps Discover Ancient Amphibian With A Venomous Bite

Jul 7, 2020

A general view of the ringed caecilian, Siphonops annulatus on leaf litter.
Credit Carlos Jared / Butantan Institute

Hikers in the mountainous west are often wary of snakes, knowing some are venomous, many of us may be less concerned about our amphibious friends, like frogs, toads and salamanders. While in tropical regions, there are poisonous amphibians, but a venomous amphibian – that’s something new.

“What we've discovered now is one group of amphibians has a venomous bite, where there are venom glands in both the upper and lower jaw that feed the venom to the base of the teeth. And these amphibians are in the caecilians group," said Edmund Brodie, a professor emeritus from Utah State University.

Brodie said caecilians are burrowers, often found in leaf litter and piles of coconut husks, with a narrow head, small eyes, strong jaws and well-developed teeth. They range from inches to about 6 feet in length, and are known to eat worms, other amphibians and reptiles and mice, when in captivity. He also said they are much older than snakes and have been around for 250 million years or more but are poorly studied.

“On the rear half of the body are poisoned glands that produce a toxin," Brodie said. "Now I want to differentiate between poison and venom. The venom associated with the teeth can be used to subdue prey.”

In the oral gland secretions of the ringed caecilian the team found a class of enzyme similar to snake venom, Brodie said. Caecilians have many small glands filled with small amounts of fluid, while snakes have less but larger glands.

“Does the very fact that caecilians have no limbs make it more important for them to have evolved oral venom to subdue prey like snakes have?” he said.

Brodie said future work for the team includes studying the specific enzymes in the venom to see if there are any biomedical applications as well as studying the evolution of these traits, the oral glands, across families of caecilians.