Capitella Blainville, 1828

Magalhães, Wagner F. & Bailey-Brock, Julie H., 2012, Capitellidae Grube, 1862 (Annelida: Polychaeta) from the Hawaiian Islands with description of two new species, Zootaxa 3581, pp. 1-52 : 3

Genus Capitella Blainville, 1828

Branchiocapitella Fauvel, 1932 . Type-species: Branchiocapitella singularis Fauvel, 1932 . syn. nov.

Type species: Capitella capitata (Fabricius, 1780) as Lumbricus capitatus . Redescribed by Blake (2009).

Diagnosis (emended after Blake 2009). Prostomium conical to bluntly rounded, sometimes dorsoventrally flattened, with dorsal groove present or absent, with nuchal organs as paired slits at border between prostomium and peristomium; eyes present or absent. Peristomium a single achaetigerous ring. Thorax with nine segments, all chaetigerous with capillary chaetae in both rami of chaetigers 1–3, 1–4, 1–6, or 1–7, otherwise with capillaries and hooks in various combinations in both rami; setigers 8–9 with hooded hooks, mixed capillaries and hooks, or all capillaries, these arrangements sometimes growth dependent; prominent genital spines present in chaetigers 8–9 of males and hermaphrodites; females usually with enlarged lateral genital pores between chaetigers 7–8 or 8–9. Capillaries unilimbate with narrow wings; hooded hooks with multiple rows of denticles above main fang. Abdominal segments with hooded hooks in both rami; capillaries absent. Branchiae present or absent. Pygidium without appendage.

Remarks. The main distinction between the genera Capitella and Branchiocapitella is the presence of filamentous branchiae on posterior segments of the latter. The presence/absence of branchiae in Capitellidae is a homoplasic character (Blake, pers. comm.); therefore, Branchiocapitella should be referred to Capitella and the presence/absence of branchiae a species level character. Branchiocapitella abranchiata Hartmann-Schröder, 1962 , is considered by Warren (1976) to be a species of Capitella , resembling those species within the Capitella capitata complex.