Salpida
Taxonomy

The systematics of this group was very confused in early studies. Solitary and aggregate forms of the same organism were often placed in different species (cf. Thompson, 1948; Foxton, 1961). Metcalf (1918) recognized a single genus, Salpa Forskål 1775, divided into 10 subgenera, 6 named by earlier authors (Cyclosalpa, Iasis, Pegea, Salpa, Thalia, and Thetys), and 4 new to science (Apsteinia, Brooksia, Ritteria, and Traustedtia). In 1919, because of prior occupation, Ritteria was replaced by Ritteriella and Apsteinia by Ihlea. Ihle and Ihle-Landenberg (1933) later raised the subgenera to genera, adding the new genus Metcalfina.

Yount (1954) recognized two subfamilies, Cyclosalpinae and Salpinae, and described two new genera: Helicosalpa and Weelia. This classification has been adopted in the present chapter (Order Salpida).

Van Soest (1973a, b, 1974a, b, 1975a, b) revised the order, raising the number of known species from about 35 (Yount, 1954; Berner, 1955; Foxton, 1961, 1971; Borgelt, 1968; Kashkina, 1973) to 44. Madin and Harbison (1978) revised the genus Pegea, describing a new species. Of the 45 species currently recognized, 29 have been recorded from the South Atlantic Ocean.