Trichobranchus Malmgren, 1866

Hutchings, Pat, Nogueira, João Miguel Matos & Carrerette, Orlemir, 2015, Telothelepodidae, Thelepodidae and Trichobranchidae (Annelida, Terebelliformia) from Lizard Island, Great Barrier Reef, Australia, Zootaxa 4019 (1), pp. 240-274 : 266-268

Genus Trichobranchus Malmgren, 1866

Trichobranchus .— Holthe 1986a: 117; 1986b: 164; Hutchings & Peart 2000: 260 –261.

Type-species. Trichobranchus glacialis Malmgren, 1866 , by monotypy.

Diagnosis. Transverse prostomium attached to dorsal surface of upper lip; basal part sometimes without eyespots; distal part at base of upper lip. Buccal tentacles all uniformly cylindrical, of two sizes in terms of thickness. Peristomium forming lips, with pair of flaring lobes; relatively short, circular upper lip; short lower lip. Short anterior segments, segment 1 dorsally inconspicuous, with large retractile mid-ventral process; following anterior segments with lobes as low ventral collars. Two or three pairs of branchiae, each with single thick and elongate filament at either side. Anterior body poorly glandular ventrally, smooth. Notopodia beginning from segments 5 or 6, terminating on segment 20; short, conical notopodia, not bilobed. Narrowly-winged notochaetae in both rows, wings inconspicuous under light microscopy, visible as short and fine hairs under SEM. Neuropodia beginning from segments 5 or 6, sessile thoracic neuropodia, uncini emerging directly from body wall; neurochaetae as acicular uncini until end of notopodia, frequently with subrostral beard; abdominal neuropodia as foliaceous pinnules, bearing avicular uncini. Nephridial and genital papillae usually inconspicuous. Pygidium smooth to slightly crenulate.

Remarks. Trichobranchus is characterized by the presence of peristomial lobes originating laterally to the lower lip and terminating dorso-laterally, and by a large, eversible mid-ventral process on segment 1, which, when retracted, is folded between segments 1 and 2. As discussed by Nogueira et al. (2010, 2013), species of this genus were considered as belonging to Artacamella Hartman, 1955 when the process of segment 1 is everted, and to Trichobranchus when it is retracted, until Garraffoni & Lana (2004) synonymised Artacamella with Trichobranchus .

The genus is currently includes eight species ( Hutchings & Peart 2000), two of which described from Australia, T. bunnabus Hutchings & Peart, 2000 and T. gooreekis Hutchings & Peart, 2000 , the latter species having been described from the southern Great Barrier Reef.