The marine red algae of Rodrigues (Mauritius, Indian Ocean) OLIVIER DE CLERCK{, ERIC COPPEJANS*{, TOM SCHILS{, HEROEN VERBRUGGEN{, FREDERIK LELIAERT{, THOMAS DE VRIESE{ and DANIEL MARIE{ {Phycology Research Group, Biology Department, Ghent University, Krijgslaan 281/S8, 9000 Ghent, Belgium {Mauritius Oceanography Institute, France Centre, Victoria Avenue, Quatre Bornes, Mauritius This paper reports on the red algae of Rodrigues, collected in the framework of the Shoals of Capricorn Programme (10 September to 5 October 2001). In total 68 species are reported, of which 65 represent new records for the island. Although most taxa represent rather common species, which are generally widespread in the Indian and western Pacific Ocean, some are of special interest to algal systematists and biogeographers. Renouxia antillana is reported for the first time for the Indian Ocean. The presence of Renouxia also constitutes the first record of the order Rhodogorgonales for the entire Indian Ocean. A few species have interesting distribution patterns. Halydictyon sp. is restricted in its distribution to South Africa, Mauritius and Australia. Despite these interesting records, the red algal flora of Rodrigues is most remarkable by the absence of several ‘ubiquitous’ species. KEYWORDS: Algae, floristics, Indian Ocean, macroalgae, Mascarene Islands, Rhodophyta, Rodrigues, seaweeds. Introduction The algae of Rodrigues have received very little attention in the past. The most detailed account of the algae from the island is by Dickie (1877) who reported on some algae collected by Balfour during a short stay of the Transit of Venus expedition in 1874. In total 52 species and varieties were enumerated, 39 of which were of marine origin, ‘a number so small that it manifestly cannot be considered a fair representation of the marine alga flora’ (Dickie, 1877: 6). Of those 39 taxa, only 14 belong to the Rhodophyceae. As part of the Shoals of Capricorn Programme, Eric Coppejans and Daniel Marie had the opportunity to sample the marine algal flora of the island, the red algae of which are reported in this paper. It should be Journal of Natural History ISSN 0022-2933 print/ISSN 1464-5262 online # 2004 Taylor & Francis Ltd http://www.tandf.co.uk/journals DOI: 10.1080/00222930410001695033 *To whom correspondence is addressed; e-mail: eric.coppejans@ugent.be JOURNAL OF NATURAL HISTORY, 2004, 38, 3021–3057