Specimens of Galaxaura rugosa (J. Ellis & Solander) J.V. Lamouroux were collected in June 2006 and June 2007 at three localities in Fernando de Noronha Archipelago (Atalaia, Porto and Cagarras), aiming to identify the epiphytic diatom flora that inhabits the algae thallus. A total of 52 taxa were identified, distributed in the classes Coscinodiscophyceae (19%), Fragilariophyceae (21%) and Bacillariophyceae (60%) with 81% dominance of individuals with pinnate symmetry. The following species characterized the floristic diatom structure being considered very frequent: Amphora sp., Biddulphia biddulphiana (J.E. Smith) Boyer, Cocconeis scutellum Ehrenberg, Diploneis bombus Ehrenberg, Grammatophora marina (Lyngbye) Kützing, Mastogloia binotata (Grunow) Cleve, Navicula longa Grunow, Nitzschia sp., Psammodiscus nitidus (Gregory) Round in Mann, Rhabdonema adriaticum Kützing, Trachyneis aspera (Ehrenberg) Cleve e Tryblionella coarctata (Grunow) Mann. Specific diversity was médium to high, with lower values for the blooming of Amphora sp. (49.3%), Mastogloia binotata (42.1%) and Nitzschia sp. (62.5%).
abundance; richness; spatial and temporal distribution; tropical region
