Studies on the systematics, heteronereid forms, swarming, and larval development of the Nereidae (Polychaeta) in Wellington Harbour

Abstract

A study of the polychaetes of family Nereidae occurring in the Wellington Harbour area showed the presence of fifteen species within genera Platynereis, Perinereis, Nereis, Neanthes, Websterinereis and Ceratonereis. This included five new species and two records new for New Zealand. The morphology of the reproductive heteronereid forms of these species is described, in most cases for the first time, and problems arising in the taxonomy of the species are discussed. Study of heteronereids of genus Platynereis reveal the presence of three species in addition to the previously recorded P. australis, although the benthic atokes are similar. The comparative morphology, possibility of interbreeding, and relationships of the Platynereis species are discussed. New species of genera Perinereis and Nereis are also described. Observations on the mating and swarming behaviour of the heteronereids are included and the comparative morphology of the heteronereids is discussed. The seasonal spawning periods of the 15 species are established, based on collection of benthic specimens and swarming heteronereids over a three-year period. Most Wellington nereids spawn in spring and early summer, but four species spawn during autumn and winter. Several species have lengthy reproductive periods. The relationship of the swarming of the heteronereids to environmental factors such as lunar period, tide and weather is studied. The swarming of each of the species is not closely synchronised although there is a concentration of swarming in the dark of the moon period and a peak at last quarter. The larval development of Platynereis australis and Perinereis camiguinoides is described in detail. Comparative larval development and larval development types in family Nereidae are discussed.