The green alga Pedobesia lamourouxii (J. Agardh) Feldmann et al. (Bryopsidales) is reported from the northern Arabian Sea on the basis of collections from the Sultanate of Oman and Socotra Island (Yemen). Vegetative and sporangial plants as well as the ecology are described. These collections constitute the first record of this widely distributed species for the Indian Ocean. In the course of this study we discovered that Bryopsis simplex Kutzing is an older taxonomic synonym, and thus we propose Pedobesia simplex (Kutzing) comb, nov. as the correct name for this species. A specimen of Bryopsis simplex in the Leiden Herbarium (L) is designated as lectotype. (C) 2001 Adac/Editions scientifiques et medicales Elsevier SAS.