Phylogenetic relationships, character evolution, and biogeography of the subfamily Lygosominae (Reptilia : Scincidae) inferred from mitochondrial DNAsequences

Phylogenetic relationships among the lygosomine skinks were inferred from 1 249 base positions of mitochondrial DNA sequences of 12S and 16S rRNA genes . The monophyly of this subfamily was confirmed and the presence of five di stinct infrasubfamilial lineages detected. Of these, the Sphenomorphus grou p appears to have diverged first, followed by the Lygosoma and Egernia grou ps in order, leaving the Eugongylus and Mabuyra groups as sister groups. Ou r results did not support monophyly of the Mabuya group sensu late (i.e., a n assemblage of the Lygosoma, Egernia, and Mabuya groups), for which a numb er of morphological and karyological studies demonstrated a considerable si milarity. Our results also contradict the previous hypothesis, formulated o n the basis of morphological and immunological data, which argued for the s ister relationship between the Egernia and the Eugongylus groups. Morpholog ical and karyological characters used to define the Mabuya group (sensu lat o) may actually represent plesiomorphic states. The phylogenetic diversity of lygosomine skinks in the Australian region appears to have increased thr ough multiple colonizations from Southeast Asia. (C) 2000 Academic Press.