Abstract
During a study on the Syllidae (Annelida) inhabiting artificial panels in the Red Sea, five species have appeared as the first colonizers in the first sampling carried out after three months: Syllis crassicirrata (Treadwell, 1925); Syllis gerlachi (Hartmann-Schroder, 1960); Syllis picta (Kinberg, 1866); Syllis schulzi (Hartmann-Schroder, 1960); and Syllis warrnamboolensis (Hartmann-Schroder, 1987). Syllis gerlachi and S. schulzi, already known from the Red Sea, are re-described on the basis of the collected material and type-specimens. The other three species, S. picta, S. warrnamboolensis and S. crassicirrata, recently re-described from Australia, are new for the Red Sea. The most abundant species, S. crassicirrata, shows an interesting variation of colour pattern, which may indicate the presence of a complex of pseudo-cryptic species. A molecular phylogeny was also performed in order to investigate the evolutionary relationships of the Red-Sea species within the genus Syllis.