Phylogenetic recontruction of SWS1 opsin evolution. Majority rule (50%) consensus tree of passerines based on concatenated mitochondrial cytochrome b and ND2, nuclear myoglobin intron 2, ODC introns 6 to 7, TGFβ2 intron 5, and protein-coding nuclear c-myc exon 3, RAG-1 and RAG-2 sequences (> 9 kbp), inferred by Bayesian inference, analysed in eight partitions, with two parrots and two falconiforms as outgroup. Posterior probabilities given at nodes, * indicating ≥0.95. Long Ailuroedus branch truncated. VS/UVS optimisation represented by violet for VS, black for UVS and dotted for ambiguous. Transitions from one state to another are indicated by numbers; 1a and 1b, and 2a and 2b, respectively, represent uncertainties due to ambiguous ancestral state. a, b and c refer to insignificantly supported nodes discussed in the text. # Sister clade, genus Malurus (not included), contains both VS and UVS species .