The first documented occurrence of Osmundea oederi (Gunnerus) G. Furnari comb. nov. in the Mediterranean Sea is reported from the Gulf of Taranto (Italy). A comparison with the morphologically similar species O. truncata and other species of Osmundea with compressed thalli and secondary pit-connections between epidermal cells occurring in the Mediterranean Sea, is presented. The conspecificity of the Caribbean Laurencia bolivarii with O. oederi is also proposed.