Atretochoana eiselti is a species of caecilian known only from two preserved specimens until its 2011 rediscovery in Brazil. Until 1998, it was known only from the type specimen in the Naturhistorisches Museum, Vienna. Originally placed in the genus Typhlonectes in 1968, it was reclassified into its own monotypic genus in 1996. It was also found to be more closely related to the genus Potomotyphlus than Typholonectes. The species is the largest of the few known tetrapods, and one of two caecilians, to lack lungs, the other being Caecilita iwokramae.A. eiselti is the largest tetrapod to lack of lungs, double the size of the next largest. Caecilians such as Atretochoana are limbless amphibians with snake-like bodies, marked with rings like those of earthworms. It has significant morphological differences from other caecilians, even the genera most closely related to it, despite the fact that those genera are aquatic. The skull is very different from those of other caecilians, giving the animal a broad, flat head. Its nostrils are sealed, and it has an enlarged mouth with a mobile cheek. Its body has a fleshy dorsal fin.