Very little is known about the origins of amphisbaena, even less for the Iberian worm lizard. Phylogenetic analysis of two nuclear genes from the tissue of a modern amphisbaena specimen and that from museum fossil samples has shed some light on the origins of amphisbaena. The data would suggest a widespread convergence of limb loss as well as skull morphology from Rhineuridae and Bipedidae lineages. DNA analysis would suggest that there were three separate incidences of limb loss all convergent for amphisbaena formation. This evidence, as well as a look into mitochondrial and genomic DNA of B. cinereus has led some experts to believe there ought to be two distinct taxonomic clades within B. cinereus located on the Iberian peninsula. While morphological characteristics are less defined between the two proposed clades, the genetic variation is incontrovertible and significant enough to make gene flow unlikely. Experts attribute these divergent potential clades, and their potential to continue to differentiate, to constraints of subterranean life. The clades are distinguished based on their locations with B. cinereus being located centrally on the peninsula and the second proposed clade Blanus mariae located on the southwestern side of the Iberian peninsula.