Rhodopsin family receptors with ambiguous relationships to other members. Groups, pairs and "single" Rhodopsin family receptors that display ambiguous relationships to other members (see material and methods). These are shown in order of decreasing sequence identity (given in the lower right corner of each box). Species-specific receptors have names in bold style. The ligand types of the receptors are indicated with the following colours; red: orphan, blue: peptide, lilac: amine, green: lipid-like, brown: purine, turquoise: opsin and black: other. The phylogenetic trees are consensus trees of 100 maximum likelihood trees for which branch lengths were calculated using TreePuzzle (see material and method). The olfactory subfamily/group of the Rhodopsin family was analysed in a separate phylogenetic analysis [see Additional files 7 and 8].