Five phyllodocidacean families (Alciopidae, Lopadorrhynchidae, Pontodoridae, Tomopteridae, and Typhloscolecidae) and two flabelligerid families (Flotidae and Poeobiidae) are dominated by transparent species (Uschakov, 1972; Glasby et al., 2000).
Polychaetes of the Suborder Phyllodociformia of the Polar Basin and the Northwestern Part of the Pacific: Families Phyllodocidae, Alciopidae, Tomopteridae, Typhloscoleicidae, and Lacydoniidae.
Of the 83 families of known polychaetes (Rouse & Pleijel, 2001), only the Tomopteridae, Alciopidae, Lopadorhynchidae, Iospilidae, Typhloscolecidae, and Pontodoridae are exclusively pelagic (Fauchald, 1977; Stop-Bowitz,1981).
Some families (e.g., Tomopteridae) are voracious predators of plankton and some species that are considered to be dominant in planktonic communities are a source of food for several types of fish (Pettibone, 1963; Fernandez-Alamo, 2000).
Rosa (1907,1908a,1908o), analyzed the Tomopteridae gathered by the Italian corvette R.N.
A total of eight species of planktonic polychaetes were determined; seven of these belong to the families Tomopteridae, Iospilidae, Lopadorhynchidae, Typhloscolecidae and one undetermined species belongs to the family Alciopidae.
In Chile's coastal waters representatives of three (Tomopteridae, Alciopidae, Lopadorhynchidae) of the six pelagic polychaete families had been found, in addition to two species of the family Polynoidae which, in spite of being essentially benthic, has two pelagic representatives (Rozbaczylo, 1985; Rozbaczylo et al., 2004).