Note: This family was established by Pedersen (1984: 50) to accommodate genera previously placed in the Ectocarpaceae but which differ chiefly in that the thallus becomes parenchymatous as a result of the formation of a few longitudinal divisions and the sporangia arise by a simple transformation of vegetative cells. Pedersen aligned the Pilayellaceae with families traditionally placed in the Dictyosiphonales and with the Tilopteridaceae in the order Tilopteridales Kylin sensu lato. While accepting the Pilayellaceae, we retain it in the Ectocarpales.
Ectocarpus antillarum Grunow, 1867: 46–47 (footnote), pl. IV: fig. 2 (type locality: Guadeloupe, West Indies).
Bachelotia antillarum (Grunow) Gerloff, 1959: 38.—Umamaheswara Rao & Sreeramulu, 1964: 599.— Umamaheswara Rao, 1969d: 40.— V. Krishnamurthy & H. Joshi, 1970: 9.— Umamaheswara Rao, 1970b: 367.— Umamaheswara Rao & Sreeramulu, 1970a: 31, fig. 21.— Umamaheswara Rao, 1974a: 300.— S. Dixit, 1980: 63.— Lawson, 1980: 20.— M. Balakrishnan & Kinkar, 1981: 5, figs. 4–7.— Untawale, Dhargalkar, & Agadi, 1983: .— Bolton, 1986: 254.— Bolton & Stegenga, 1987: 170.— Seagrief, 1988: 42.— Bolton & Stegenga, 1990: 234, 237.
INDIAN OCEAN DISTRIBUTION: India, South Africa, Tanzania (Zanzibar).