New species of Terebellides (Polychaeta: Trichobranchidae) from the deep Southern Ocean, with a key to all described species.

The genus Terebellides is, despite its often low abundances, a common and diverse element of benthic, soft sediment communities at all depths. In recent years, careful examination of specimens has resulted in numerous descriptions of new species of Terebellides increasing the number of species in the genus to over forty. For the Southern Ocean currently only two species are considered valid, both recorded for shelf and slope depths. Here, we present findings of eleven new Antarctic species originating from depths between 480 m and 4720 m. Six of these are formally described (T. canopus sp. n., T. crux sp.n., T. mira sp.n., T. rigel sp.n., T. sirius sp.n., and T. toliman, sp.n.). One species, T. crux sp.n., bears two segments with geniculate hooks, a trait already known for the genus but conflicting with the original generic diagnosis. To include this trait the generic diagnosis of Terebellides is amended. An identification key for all species of Terebellides is given, as well as a maximum parsimony phylogeny of the genus based on morphological characters.