West J.A., Zuccarello G.C., Loiseaux de Goer S., Stavrias L.A. & Verbruggen H. (2016)
Rhodenigma contortum, an obscure new genus and species of Rhodogorgonales (Rhodophyta) from Western Australia
Journal of Phycology 52: 397-403


An unknown microscopic branched filamentous red alga was isolated into culture from coral fragments collected in Coral Bay, Western Australia. It grew well unattached or attached to glass with no reproduction other than fragmentation of filaments. The cells of some branch tips become slightly contorted and digitate, possibly as a substrate-contact-response seen at filament tips of various algae. Attached multicellular compact discs on glass have a very different cellular configuration and size than the free filaments. In culture the filaments do not grow on or in coral fragments. Molecular phylogenies based on four markers (rbcL, cox1, 18S, 28S) clearly shows it belongs to the order Rhodogorgonales, as a sister clade of Renouxia. Based on these results, the alga is described as the new genus and species Rhodenigma contortum in the Rhodogorgonaceae. It has no morphological similarity to either of the other genera in Rhodogorgonaceae and illustrates the unknown diversity in cryptic habitats such as tropical coral rubble.

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