A phylogenetic tree of the five photoreceptor opsins of Neoceratodus forsteri and selected full-length nucleotide coding sequences of related species. The tree was constructed using the Neighbour-joining method with 1000 bootstrap replications . Sarcopterygian fish (coelacanth and lungfish) are in red, agnathan fish (lamprey) are in light blue, teleost fish are in dark blue, amphibians are in green and reptiles are in purple. Genbank accession numbers are listed in Table 1. Bootstrap confidence values are at the base of each node. The rh4 opsin of Drosophila melanogaster (Table 1) was used as an outgroup. Scale bar indicates nucleotide substitutions per site.