Leuckart, 1849:169. Malmgren, 1866:386–387 (emend.).— Hessle, 1917:212.— Hutchings & Glasby, 1986:112.— Hartmann-Schröder, 1996:528.— Capa & Hutchings, 2006:23.
Synonyms: Lumara Stimpson, 1854; Phenacia de Quatrefages, 1865; Venusia Johnston, 1865; Heterophenacia de Quatrefages, 1865; Neottis Malmgren, 1866; Thelephusa Verrill, 1871; Thelepodopsis Sars, 1872; Protothelepus Verrill, 1900; Terebellanice Hartmann-Schröder, 1962.
Type species: Amphitrite cincinnatus Fabricius, 1780, by subsequent designation.
Diagnosis: Zero to three pairs of digitate and sessile branchiae from segment 2; eyespots sometimes present; lateral lappets absent; ventral shields from segment 2; nephridial papillae present on range of segments 2–8; variable number of pairs of notopodia from segment 3; chaetae smooth-tipped, limbate, or oar-like; pairs of neuropodia from segment 5 until posterior end; uncini avicular, subrostral process button-shaped.
Remarks: According to Holthe (1986b), there are no valid species described from the Grand Caribbean region; Thelepus crassibranchiatus Treadwell, 1901, from Porto Rico, was regarded as a junior synonym to T. cincinnatus (Fabricius, 1780), from Greenland, by Hartman (1959). Thelepus haitiensis Treadwell, 1931, from Haiti, was likewise regarded as a junior synonym to T. setosus (de Quatrefages, 1865), from France and the latter considered cosmopolitan. Nevertheless, type specimens of these synonymized species were compared with non-type specimens from the type locality of T. cincinnatus and T. setosus, and some important morphological differences were found. On the other hand, Hutchings and Glasby (1986) regarded both Euthelepus pascua Fauchald, 1977, from Panama, and Euthelepus tenuis (Verrill, 1900), from Bermuda, as members of Thelepus because of the absence of lateral lappets. Streblosoma verrilli Treadwell, 1911, belongs in Thelepus because it has notopodia from segment 3, instead of notochaetae from segment 2, as in Streblosoma. Finally, Londoño-Mesa and Carrera-Parra (2005) reported Thelepus sp. from the Mexican Caribbean and Gulf of Honduras. Thus, after this revision, the Grand Caribbean region has six distinct species: five valid ones and one unnamed.