Ra. Nussbaum et M. Wilkinson, A NEW GENUS OF LUNGLESS TETRAPOD - A RADICALLY DIVERGENT CAECILIAN (AMPHIBIA, GYMNOPHIONA), Proceedings - Royal Society. Biological Sciences, 261(1362), 1995, pp. 331-335
Lunglessness is rare in the Tetrapoda and previously recorded only in
salamanders (Amphibia: Caudata). Here we report lunglessness in anothe
r group of tetrapods, the poorly known tropical caecilians (Amphibia:
Gymnophiona). Typhlonectes eiselti is a lungless, aquatic caecilian fr
om South America known only from the single holotype specimen, NMW 914
4 (Vienna Museum of Natural History). At a total length of 725 mm, NMW
9144 is by far the largest known lungless tetrapod. It also has a sta
rtling array of other radically divergent morphological features, many
unique, and some correlated with lunglessness including: sealed choan
ae (paired internal nostrils); complete absence of pulmonary blood ves
sels; a repatterned skull with post-occipital jaw articulation; and a
novel cranial muscle associated with an elongate and redirected stapes
. This remarkable combination of highly derived characters sets Typhlo
nectes eiselti apart from all other caecilians and places it on a nove
l evolutionary trajectory. A new genus is described to accommodate thi
s form.