Note: As pointed out by Woelkerling, Chamberlain, & P. Silva (1985), Titanoderma Nägeli (1858: 532, footnote) is an earlier nomenclatural synonym of Dermatolithon Foslie (1898a: 11), both having as their type Melobesia pustulata Lamouroux (1816: 315, pl. XII: fig. 2). According to Woelkerling (1988: 111), Titanoderma differs from all other genera of Corallinaceae subfamily Lithophylloideae in having the combined features of a thallus with a dorsiventral internal organization in crustose portions and primigenous filaments composed of palisade cells. Campbell & Woelkerling (1990), in a study concentrating on the occurrence of palisade cells in six species currently assigned to Titanoderma, concluded that this genus cannot be separated from Lithophyllum on the basis of the presence or absence of these cells. Moreover, they found no other criteria to delimit the two genera. While agreeing that the shape of the hypothallial cells does not unequivocally distinguish between the two genera, Chamberlain, L. Irvine, & Walker (1991) argued for the retention of Titanoderma on other anatomical bases. Woelkerling & Campbell (1992: 17–18), who maintained that these other characters are unsatisfactory, continued to recognize only one genus, Lithophyllum.
Melobesia corallinae P. Crouan & H. Crouan, 1867: 150, pl. 20: fig. 133 bis: 7–11 (type locality: near Brest, Finistère, France).
Dermatolithon corallinae (P. Crouan & H. Crouan) Foslie in Børgesen, 1902: 402.—Pocock, 1958: 26 (with query).
Titanoderma corallinae (P. Crouan & H. Crouan) Woelkerling, Chamberlain, & P. Silva, 1985: 333 (table 2).—Chamberlain & R. Norris, 1994a: 14.
INDIAN OCEAN DISTRIBUTION: Mozambique?, South Africa.