Frogs, toads, salamanders and other amphibians rarely make anyone’s favorite animal list (except perhaps for the psychedelic Colorado River toad), but they don’t pop up on the mast-fear lists either (except for the poisonous frogs of the poison dart kind). That may change with the recent discovery of the world’s first venomous amphibian – a limbless creature that resembles a scary cross between a worm and a snake but with teeth that deliver a deadly bite. Are you ready for Attack of the Killer Amphibians?
“We show here that amphibian caecilians, including species from the basal groups, besides having cutaneous poisonous glands as other amphibians do, possess specific glands at the base of the teeth that produce enzymes commonly found in venoms. Our analysis of the origin of these glands shows that they originate from the same tissue that gives rise to teeth, similar to the venom glands in reptiles. We speculate that caecilians might have independently developed mechanisms of production and injection of toxins early in their evolutionary history.”
You have to be a herpetologist to know that caecilians are rare tropical amphibians found primarily in the wet jungles of Central America and South America, and occasionally in Africa, and southern Asia. While reaching snakish lengths of up to 1.5 meters (5 feet), they more resemble giant worms but with poisonous glands that would take them off the menu of giant robins or bass. The name caecilian comes from the Latin word caecus, meaning “blind,” and refers to their tiny eyes, which are mostly invisible but sometimes missing completely. Throw in the fact that they live and die in moist jungles and it’s easy to see (unless you’re a caecilian) why little is known of the evolution or traits of this strange creature.
Tell me more!
“You have to jump on it.”
In an interview with The New York Times discussing the release of his study published in the journal iScience, Carlos Jared, a biologist at the Butantan Institute in Brazil, talks about wrestling caecilians (note: good movie scene) deep in the jungle, only to lose them as they wiggle free after covering him with slime. Jared says he’s always careful to avoid the venomous glands while trying not to squeeze or scoop the giant worm-like wigglers to hard or they break in two … and, unlike some worms, neither end lives on. However, he managed recently to get enough so his partner, post-doctoral scholar Pedro Luiz Mailho-Fontana, could hatch some babies and watch them grow. He was particularly interested in the venomous glands.
“This is a very different thing here.”
That’s when Mailho-Fontana saw something unexpected. As the caecilians’ baby teeth formed (caecilians need teeth to catch and eat worms and insects), venomous glands appeared next to them. These had never been seen before in adult caecilians whose mouths are typically full of slime. (Photos here.) The glands are also difficult to get to in adults, so the researchers haven’t yet identified the toxins they secrete, although it appears to be similar to that of venomous snakes and insects. The researchers also haven’t seen the end results of a caecilian biting and killing a prey, although Marta Maria Antoniazzi, a co-author of the study, claims she was bitten by a small one and “It hurt a lot” while taking a long time to heal.
An early drawing of a caecilian guarding her eggs.
“Based on our data we suggest that caecilians developed the ability to actively inoculate toxins through their teeth early in their evolutionary history, probably representing one of the first terrestrial vertebrates having an oral venom system.”
Despite limited data so far, the researchers felt confident to conclude that caecilians could be one of the first land vertebrates to develop a venomous bite. Warning: they also offered no evidence that the bite can result in a psychedelic experience, so don’t go rushing to Brazil with a sack, a bucket of worms and collection of Jefferson Airplane music.
On the other hand, ‘The Bite of the Killer Worm’ definitely has movie possibilities.
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