Genus Naineris Blainville, 1828

Type species. Naineris quadricuspida (Fabricius, 1780)

Diagnosis (amended from Blake 2020; Zhadan 2020). Prostomium rounded, truncated, or weakly bifid on anterior margin. Peristomium with one or two achaetous rings. Thorax with 12–30 or more segments; branchiae first present from chaetigers 2–23. Thoracic neuropodia with 0–2 postchaetal lobes; no subpodial lobes. Thoracic neurochaetae include capillaries, or capillaries mixed with blunt-tipped uncini, sometimes hooded, or uncini and subuluncini. Abdominal chaetae include capillaries, sometimes furcate chaetae in notopodia, and capillaries and embedded or protruding aciculae in neuropodia. Dorsal sensory organs present in some species, being paired or multiple, rounded or as elongated semicircles. Dorsal cilia within branchiae bases present, either forming flat bands or crests.