ON THE PHYLOGENETIC POSITION OF THE URAEOTYPHLIDAE (AMPHIBIA, GYMNOPHIONA)

The taxonomic history of the monogeneric caecilian family Uraeotyphlid ae and hypotheses concerning its phylogenetic position are briefly rev iewed. Previous phylogenetic analyses identified Uraeotyphlidae as sis ter to a ''higher'' caecilian clade that includes the families Caecili aidae, Scolecomorphidae, and Typhlonectidae. However, two distinctive derived features of the cardiovascular system are characteristic of Ur aeotyphlidae and Ichthyophiidae and provide support for the alternativ e hypothesis that they are sister taxa. Characters of significance for phylogenetic relationships of Uraeotyphlidae are reviewed. Parsimony analysis of a combined data set, including new characters and others d rawn from the literature, supports the hypothesis that Uraeotyphlidae is sister to the Ichthyophiidae; the new characters are instrumental i n producing this result. A compatibility analysis lends further suppor t to this conclusion.