Caecilian phylogeny and biogeography inferred from mitochondrial DNA sequences of the 12S rRNA and 16S rRNA genes (Amphibia : Gymnophiona)

The classification and phylogeny of the caecilians has received much attention in the past decade, yet no consensus has been reached. We present new mitochondrial ribosomal gene sequence data from 13 caecilian species representing 10 genera from four of the six recognized families. Out of 1208 total sites, 890 were aligned, 475 were variable, and 329 were informative under the parsimony criterion. A phylogeny for these taxa supports the Caudata (as represented by Amphiuma) as the sister lineage to the Gymnophiona, the basal position of the Rhinatrematidae and Ichthyophiidae, the paraphyly of the Caeciliaidae, and the monophyly of the Seychellean caecilians. These sequence data support previous morphological studies suggesting that the typhlonectids were derived from Neotropical caeciliaids, and therefore the Typhlonectidae is synonymized within the family Caeciliaidae. Species previously placed in the Typhlonectidae are assigned to a separate subfamily (Typhlonectinae) of the Caeciliaidae. Resolution of relationships within the largest family, the Caeciliaidae, remains the major task of caecilian systematics.