Sphaerosyllis sandrae sp. nov. (Annelida: Polychaeta: Syllidae) is described as a new species from shallow sandy bottoms off Guanahacabibes Biosphere Reserve (Cuba). Thirteen more syllid species belonging to nine genera (Exogone, Myrianida, Opisthosyllis, Parexogone, Plakosyllis, Salvatoria, Syllides, Sphaerosyllis and Syllis) have been found from algal and sand bottom samples from the same area; four species that belong to the genera Myrianida, Syllides and Parexogone are only identified at the generic level.
