Fig. 2
From: Sea as a color palette: the ecology and evolution of fluorescence
Distribution of fluorescent proteins in metazoan. Canonical GFPs have been found in cnidarian, arthropods and cephalochordates, supporting the hypothesis of a common metazoan ancestral origin. Color expansion is present in cnidarians and has been recently showed in cephalochordates as well. Furthermore, two other FPs, not related to GFP, have been characterized in vertebrates: UnaG and Sandercyanin