Molecular phylogenetics reveals extreme morphological homoplasy in Brazilian worm lizards challenging current taxonomy

Amphisbaenians are fossorial squamate reptiles distributed mainly in South America and Africa. Brazilian worm lizards belong to the family Amphisbaenidae, which has far more recognized species than any of the other five amphisbaenian families. Morphological datasets recovered Amphisbaenidae as paraphyletic, while previous molecular phylogenetic studies did not include enough taxa to solve the generic-level relationships within this family. We present a molecular phylogenetic hypothesis based on a sample of 58 amphisbaenians, including representatives of six of the seven South American genera. Our molecular data include sequences from two mitochondrial genes (16S, ND2; 1,184 characters) and three nuclear genes (RAG-1, C-MOS, BDNF; 1,898 characters). Our phylogenetic hypothesis is not fully resolved, although it does not support the monophyly of most genera except Leposternon. Morphological characters currently used to diagnose genera of South American amphisbaenians are homoplastic, and the taxonomy based on them is not appropriate. We revise the taxonomy of this group and sink several South American genera of Amphisbaenidae (Cercolophia, Bronia, Aulura, Anops and Leposternon) into Amphisbaena.