Polychaeta
Geographic distribution

Since the middle part of the twentieth century, strong correlations between the distributions of planktonic animals and the movements of water masses in the oceans have been established. Tebble (1960) has demonstrated such correlations for some species of pelagic polychaetes in the South Atlantic Ocean, and Tebble (1962) and McGowan (1960) for pelagic polychaetes in the North Pacific Ocean. Støp-Bowitz (1948) found differences between the pelagic polychaete fauna in the western and eastern parts of the North Atlantic Ocean, the western part being richer, both in species and abundance. In addition, some species occur only in the eastern half while they are absent in the western half, and vice versa. Orensanz and Ramírez (1973) have studied the distribution of pelagic polychaetes in the southwestern Atlantic Ocean. They recorded 27 species from the families Lopadorhynchidae, Iospilidae, Alciopidae, Typhloscolecidae and Tomopteridae, and also some larval and epitokous forms. Orensanz et al. (1974) described the distribution of nine polychaete species from antarctic waters near Argentina. Støp-Bowitz (1992) has documented the distribution of pelagic polychaetes in the eastern South Atlantic off the coast of the Africa between the equator and about 20°S.

The distributions of some holoplanktonic species have been mapped by Tebble (1960) in the South Atlantic Ocean. He discusses their zoogeographical patterns, and describes endemic, cosmopolitan and tropical-subtropical species. Tebble (1960) concluded that although there were three endemic species of antarctic pelagic polychaetes, there were no endemic species of pelagic polychaetes in the subantarctic Atlantic. He also noted that the Subtropical Convergence was not a barrier to the distribution of any planktonic polychaete species. Five species (Tomopteris planktonis, T. septentrionalis, Typhloscolex mulleri, Travisiopsis levinseni and Pelagobia longicirrata) were found in all the investigated hydrological zones of the South Atlantic Ocean. The Discovery samples that Tebble (1960) analyzed also included some specimens collected with opening-closing nets, and he provided some depth distribution data. However, much more work is needed in order to properly elucidate the bathymetric ranges of pelagic polychaetes. Distribution records of 63 species of pelagic Polychaeta in the South Atlantic Ocean are shown.