The Black Phoronid worm (Phoronis australis) is a small black worm species that belongs to the family Phoronida, which are also commonly referred to as ‘Horseshoe Worms’. Phoronids are sedentary infaunal species that are benthic suspension feeders that have a body enclosed in a slender tube, which it moves freely. The end of tube is anchored by the ampulla that is the end bulb of the body. Phoronis australis is always attached under the sediment surface to the tube of Cerianthus anemones, in particular the Banded Tube Anemone (Pachycerianthus delwynae). This species is generally found in silty/sandy inshore estuaries and harbours from depths of 1 to 30 metres.
The Black Phoronid worm (Phoronis australis) has a maximum length of approximately 20cm.