Diopatra Audouin & Milne Edwards, 1833: 229.—Paxton 1986: 38. Epidiopatra Augener, 1918: 355.— Budaeva & Fauchald 2011: 335.
Type-species. Diopatra amboinensis Audouin & Milne Edwards, 1833: 229, by subsequent designation of Malmgren 1866:180. Gender: feminine.
Diagnosis. Prostomium anteriorly rounded to slightly extended, with subulate frontal lips. Antennae and palps with ceratophores with five to 20 rings (sometimes with lateral projections) and moderately long to long styles. Nuchal grooves crescentic to almost circular; peristomial cirri usually present, rarely absent. Anterior three to five (rarely seven) pairs of parapodia modified, slightly enlarged, rarely with double postchaetal lobes. Small ventral parapodial lobes on chaetigers 5–25 in some species; ventral cirri on anterior four to six chaetigers, dorsal cirri long to very long. Branchiae from chaetiger 4–5, filaments arranged spirally around stem. Hooks of modified parapodia simple to pseudocompound with uni- to tridentate tips and short to pointed hoods. Dorsal limbate chaetae from chaetiger 1, ventral limbate chaetae replacing falcigers from chaetiger 4 or later until replaced by bidentate hooded subacicular hooks usually from chaetiger 15–20. Tubes robust, consisting of inner secreted layer and outer layer of sand and mud, typically with boken shells or vegetational matter attached at right angle.
Remarks. The absence of peristomial cirri was the only character separating Epidiopatra from Diopatra. Budaeva & Fauchald (2011) studied the inter-relationships of the Diopatra complex, identified Epidiopatra as a polyphyletic taxon and attributed the lack of peristomial cirri in Epidiopatra to paedomorphic evolutionary events, concluding that Epidiopatra is a junior synonym of Diopatra.