Platynereis Kinberg, 1865

Platynereis Kinberg 1866

Diagnosis. Proboscis with chitinous paragnaths in form of parallel rows of minute pectinate bars usually
present on all areas except I, II, and V. Prostomium with 2 antennae, biarticulate palps, and 2 pairs of eyes; 4 pairs of tentacular cirri. Peristomial segment apodous and first 2 parapodia sub-biramous. Chaetae include spinigers and falcigers. Homogomph notopodial falcigers usually present, at least in juveniles.

Nereidids with distinctive metamorphosed reproductive forms with natatory parapodia and other specialisations for reproduction are usually known as heteronereids, after the genus Heteronereis first erected for the distinctive swimming forms (thus Heteronereis australis now Platynereis australis), but soon discovered to be a lifecycle category, as subsequently was Nectonereis (for N. megalops). The characters of metamorphosed heteronereids are of considerable importance in Platynereis taxonomy. Recent morphology-based parsimony analyses of taxa selected as representative of the Nereididae genera have maintained Platynereis as monophyletic.