Note: Derbesia Solier (1846: 452) has been shown to be the sporophyte in a life history of which Halicystis Areschoug (1850b: 446) is the gametophyte. Not all species of Derbesia, however, have been paired with gametophytes. Halicystis has been recorded from eastern Cape Province, South Africa (R. Anderson & Stegenga, 1989: 302, 306), but the identity of its sporophyte is not known.
Derbesia attenuata Dawson, 1954d: 390, figs. 9a,b (type locality: Nha Trang Bay, Vietnam).—Hackett, 1977: 25.— Russell, 1981: 466.
INDIAN OCEAN DISTRIBUTION: Chagos Archipelago (Egmont Atoll), Maldives.
Note: The gametophyte of Derbesia attenuata is not known. According to Calderón & Schnetter (1991: 293), this species may be referable to their new genus, Pseudoderbesia.