First evidence of snake-like venom glands found in amphibians
Caecilians are limbless amphibians that, to the untrained eye, can be easily mistaken for snakes. Though caecilians are only distantly related to their reptilian cousins, researchers in a study appearing July 3 in the journal iScience describe specialized glands found along the teeth of the ringed caecilian (Siphonops annulatus), which have the same biological origin and possibly similar function to the venom glands of snakes. If further research can confirm that the glands contain venom, caecilians may represent the oldest land-dwelling vertebrate animal with oral venom glands.
Caecilians are peculiar creatures, being nearly blind and using a combination of facial tentacles and slime to navigate their underground tunnels. "These animals produce two types of secretions--one is found mostly in the tail that is poisonous, while the head produces a mucus to help with crawling through the earth," says senior author Carlos Jared, a biologist and Director of the Structural Biology Lab at the Butantan Institute in São Paulo. "Because caecilians are one of the least-studied vertebrates, their biology is a black box full of surprises." ...
"The poisonous skin glands of the ringed caecilian form from the epidermis, but these oral glands develop from the dental tissue, and this is the same developmental origin we find in the venom glands of reptiles," says Mailho-Fontana. This marks the first time glands of this kind have been found in an amphibian.
Researchers suspect that the ringed caecilian may use the secretions from these snake-like oral glands to incapacitate its prey. ...
