Platynereis australis (Schmarda, 1861)
Reproduction. Metamorphosis to distinct male and female heteronereids free-swimming at night. Swarming occurs over an extended period of late autumn to summer at Wellington, New Zealand.
Habitat. Intertidal to shallow subtidal in sand and sandy mud substrates. A tough, stringy flexible tube is formed out of detritus and secretions.
Distribution. New Zealand mainland islands and Chatham Islands. Populations further south than about 47 degrees may occur, but are yet to be proven to be present.
Platynereis australis was based on a single metamorphosed female collected from Auckland Harbour, New Zealand (about 37 degrees South) by Schmarda, and has since been widely reported, apparently occurring extensively across the Subantarctic. These reports need re-evaluation since Read's (2007) more circumscribed redescription.
Diagnosis: Secondary-tooth-tipped homogomph falcigers in juveniles, with replacement ceasing when about 50 chaetigers developed; homogomph falcigers absent in adults. Male heteronereid 2-part, 27 (26–28) prenatatory segments, pygidial papillae structure a complex rosette. Female heteronereid 3-part, 33 (32–34) prenatatory segments, eggs white to pale golden-yellow. Benthic atoke dark green anteriorly with some brown pigment on blunt thickened lobes of chaetiger 5–11, on prostomium, and oral proboscis ring.