| Abstract: | Phyllogorgia dilatata is a Brazilian endemic gorgonian with a natural color ranging from white to pale yellow. An unusual violet pigmentation has been observed in colonies with tissue damage and skeleton anomalies. In order to investigate the chemical composition of these pigments, we have used in situ Raman spectroscopy to characterize the white/cream and violet tissues as well as sclerites, a skeletal component consisting of calcite, from both samples. Violet/purple pigmentation surrounding tissue necrosis is characterized as purpling, in response to fungus infection and allelopathic interactions. The spectroscopic analysis of the white‐cream tissues, designated as healthy, has revealed the presence of the carotenoid peridinin, typical of the endosymbiont that harbors this species; however, peridinin was not observed in the colorless sclerites analysis, presenting bands exclusively of calcite. In contrast, the violet coloration of damaged tissue has also been observed in the sclerites. Both showed Raman bands corresponding to unmethylated polyunsaturated aldehyde, besides calcite bands. This is the first report of purpling in a Brazilian octocoral, identified as a derivative of the biochromes named psittacofulvins, which have been reported as exclusive in parrots. Copyright © 2011 John Wiley & Sons, Ltd. |
