Amphitritides Augener, 1922

Bick, Andreas & Zettler, Michael L., 2024, Description of three new species of Amphitritides Augener, 1922 (Terebellida, Annelida) from the coast of Namibia (South West Africa), Zootaxa 5446 (1), pp. 42-64 : 45

Amphitritides Augener, 1922

Type species: Terebella gracilis ( Grube, 1860) , by subsequent designation.

Diagnosis (after Hutchings et al. 2021b, slightly emended (in bold )). The diagnoses of the genera Amphitritides and Amphitrite , for which a synonymisation is discussed (see Introduction), are similar in many characters. Amphitritides is distinguished from Amphitrite by the characters in italics below.

Transverse prostomium attached to dorsal surface of upper lip; basal part as thick crest, eye spots may be present, but may fade when stored in alcohol; distal part shelf-like. Buccal tentacles all usually uniformly cylindrical. Peristomium forming lips and continuing dorsally for short extension, not forming a complete ring; lips expanded, relatively short upper lip, hood-like, about as long as wide, distal margin rounded, slightly or distinctly undulated; narrow, rectangular, mid-ventral lower lip. Segment one conspicuous all around, dorsally narrow, ventrally developed, with mid-ventral lobe marginal to mouth; other lobes on anterior segments absent. Anterior segments highly glandular ventrally, with discrete, smooth to slightly corrugated, rectangular to trapezoidal shields. Two pairs of short, arborescent branchiae, on segments two and three, with short or long main stalks. Rectangular to conical notopodia beginning on segment 4, extending a variable number of segments; notochaetae all medially winged and finely serrated distally, with or without basally bulbous wings. Neuropodia beginning on segment 5, as low, sessile ridges throughout; neurochaetae as short-handled avicular uncini, in completely separate double rows, beak-to-beak arrangement, from segment 11 until termination of notopodia or posterior body. Nephridial papillae on segment 3, genital papillae on some anterior segments, beginning from segment 6, between parapodial lobes or at anterior bases of notopodia.

Remarks. In addition to the presence of lateral lobes on the anterior segments, the serrated notochaetae are also described as having no bulbous wings at the base and the uncini are arranged in partially intercalated double rows in Amphitrite . But there is also an overlap in the presence of these uncini double rows in the neuropodia. In Amphitrite , they are supposed to be present almost exclusively in the thorax region, while in Amphitritides they extend to the posterior end of the body. However, there are several exceptions. In Amphitrite rubra ( Risso, 1826) and A. vigintipes ( Grube, 1870) (but Neoamphitrite vigintipes in WoRMS, Read & Fauchald 2024b), for example, the double rows of uncini extend almost to the posterior end ( Jirkov 2020), whereas in Amphitritides pectinobranchiata Hartmann-Schröder, 1965 they are only present in the thoracic region ( Hartmann-Schröder 1965).

As described in the introduction, we follow here the views of Hutchings et al. (2021b) and Lavesque et al. (2021) who proposed the separation of Amphitrite and Amphitritides , and a synonymisation of Neoamphitrite with Amphitrite .

Worldwide, seven species have been described so far: Amphitritides bruneocomata ( Ehlers, 1887) from Florida, USA, A. carawa Nogueira & Hutchings, 2007 , from NS Wales, Australia, A. gracilis ( Grube, 1860) from Great Britain, A. harpa Hutchings & Glasby, 1988 and A. ithya Hutchings & Glasby, 1988 from Queensland, Australia, A. kuehlmanni Arvanitidis & Koukouras, 1995 from Greece, and A. pectinobranchiata Hartmann-Schröder, 1965 from Chile.