The Italian expeditions made on board the Liguria (1903-1905) included sites in western Mexico; as part of these cruises, Rosa (1907, 1908) described species of the planktonic families Tomopteridae and Alciopidae.
Family Tomopteridae Grube, 1848 Tomopteris (Johnstonella) aloysii sabaudiae Rosa, 1907: 176; 1908: 274, pl.
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.
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).
Rosa (1907,1908a,1908o), analyzed the Tomopteridae gathered by the Italian corvette R.
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.