<i>Schimmelmannia elegans</i> (Gloiosiphoniaceae, Rhodophyta): South Africa’s first introduced seaweed?

Although there are a number of records of recently introduced marine animals in South African waters, there has never been good evidence of a seaweed introduction. Schimmelmannia elegans, a red alga previously only known from Tristan da Cunha and Nightingale Island, is reported for the first time for South Africa. The plants were found growing in the Kelp Tank of the Two Oceans Aquarium in Cape Town. The morphology and reproduction of the specimens are described in detail and agree in all aspects with the original account of S. elegans. Several hypotheses on the arrival of this newcomer along the South African coast are discussed: previously overlooked, present as a different life history stage, or recently introduced. Of these, recent introduction seems the most plausible. In this context, the spread and potential ecological significance of an introduced seaweed species are discussed