The largest lungless tetrapod: report on a second specimen of Atretochoana eiselti (Amphibia: Gymnophiona: Typhlonectidae) from Brazil

Abstract

The discovery is reported of a second specimen of the radically divergent lungless aquatic caecilian Atretochoana eiselti (Taylor), previously known only from the holotype. Aspects of the morphology of the second specimen are described and compared to the holotype, allowing a minimal evaluation of variation within this enigmatic species. With a total length of 805 mm, the second specimen is the largest known lungless tetrapod. Most of the distinctive morphological features reported for the holotype are true of the second specimen also indicating that the holotype is not a ‘hopeful monster’. An important exception, from the perspective of species identification, is variation in the form of the pattern of denticulations about the cloacal disk. Although precise locality data are lacking for both the holotype and the second specimen, the latter specimen was almost certainly collected more recently and from within Brazil. This justifies increased expectation that this remarkable species is still extant and that it will be rediscovered.

Keywords :

• Atretochoana
• Typhlonectidae
• Gymnophiona
• Caecilian
• lunglessness
• Neotropics
• Brazil