A new species of Ophryotrocha (Annelida: Dorvilleidae) associated with fish farming at Macquarie Harbour, Tasmania, Australia

Ophryotrocha shieldsi, sp. nov. is described from Macquarie Harbour, Tasmania, Australia, where it occurs in high densities beneath the sea cages of fish farms. SCUBA and ROV underwater observations revealed closely spaced mounds of aggregations of the new species. It is closely related to O. lobifera Oug, a species reported from fish farms and whale-falls in the North Sea, from which it can be distinguished by its ovate rather than triangular dorsal lateral lobes, palps with small globular rather than longer digitate palpostyles, and additional jaw differences.