Molecular systematics of social skinks: phylogeny and taxonomy of theEgerniagroup (Reptilia: Scincidae)

The lizards of the Egernia group of Australia and Melanesia include some of the most distinctive members of the family Scincidae in morphology (including giant size, spinose scalation), ecology and behaviour. Social behaviour, including long-term recognition of individuals and kin, mate fidelity and home site fidelity, is amongst the most complex known in squamate reptiles and is the subject of an expanding number of studies. Lack of a sound phylogeny for the Egernia group has limited our ability to understand the evolution and patterns of variation in social behaviour within this group, and evidence for the monophyly of the largest genus, Egernia (64% of the species), has been lacking. We present data derived from nucleotide sequences that establish a phylogenetic framework for the Egernia group. We used two mitochondrial sequences, the protein-encoding ND4 gene and a ribosomal gene, 12s rRNA, and two nuclear sequences, the protein-encoding c-mos, and non-encoding intron 7 of β-fibrinogen. Our phylogenetic analyses show that Corucia of the Solomon Islands is the sister group of the rest of the Egernia group. The genus Egernia is paraphyletic, including four well-supported monophyletic units, one of which is the sister lineage of the Tiliqua lineage (Tiliqua plus Cyclodomorphus). We suggest a revised taxonomic scheme that recognizes the major monophyletic lineages in Egernia (s.l.) as distinct genera.