Chthonerpeton
Chthonerpeton is a genus of semiaquatic caecilian amphibians in the family Typhlonectidae. They occur in South America east of the Andes, with most species occurring along the Brazilian Atlantic coast.
With ten currently recognized species, Chthonerpeton is the most speciose genus within Typhlonectidae.
Species are characterized by having several diagnostic traits, including small ovate external nares, tentacular apertures located at an intermediate position between the eye and naris, and unroofed tentacular grooves.
Phylogenetically, Chthonerpeton is often recovered as the sister taxon to all other typhlonectids and retains plesiomorphic features, such as a subcylindrical body and the absence of fins.