Toward the phylogeny of the family Lacertidae - Why 4708 base pairs of mtDNA sequences cannot draw the picture

Abstract

A phylogeny of the family Lacertidae was derived from DNA sequences of six mitochondrial genes. Only a few nodes were confidently resolved using maximum parsimony, although the data yielded a total of 1664 phylogenetically informative characters. The lacertids grouped into two subfamilies, the Gallotiinae which includes genera Gallotia andPsammodromus , and the Lacertinae which includes the remaining lacertids. The Lacertinae split into two additional groups. The African group included all African and Arabian lacertids and two Eurasian genera, Eremias and Ophisops; the remaining Eurasian lacertids were included in the Eurasian group. Most of the relationships within the African and Eurasian groups cannot be confidently resolved. A permutation tail probability test suggested that there is very little character covariance in the data to support these unresolved relationships. A recent explosive speciation hypothesis was invoked to explain the lack of structure of the data. The common ancestor of the Eurasian group, as well as the ancestor of the African group, experienced simultaneous, or almost simultaneous, multiple speciation events, which left none or very few characters fixed on the internodes. The phylogenetic reconstruction at the family level will be very difficult, if not impossible. Future phylogenetic research should focus on lower levels.