Arenicolids (or lugworms) are found throughout the world. They are large, thick-bodied worms with rather thinner tails, reportedly growing to over 1 metre in length. They are sold as fish bait in many areas.
Arenicolids are infaunal polychaetes which construct U-shaped burrows in mud and sandy substrates in esatuaries and intertidal beaches. Sediment is ingested by the eversible proboscis, causing a sediment depression at the head end of the burrow. In the United Kingdom and Europe, species of arenicolids are often found in large numbers on intertidal mud flats and produce characteristic coiled faecal pellets which lay in the ripples on the beach. Australian species appear not to reach these densities.
Diversity
There are 4 genera and 28 species of Arenicolidae in the world. Australia has only 2 genera and 8 species represented in it's waters.
All known Australian species included - 3 species and 5 subspecies, representing 2 genera - are based on published descriptions. The 2 non-Australian genera are included in this database as well. The principal areas surveyed are Bass Strait and Port Phillip Bay (material held in Museum Victoria, Melbourne) and Jervis and Botany Bays (material held in Australian Museum, Sydney). Many taxa undoubtedly remain to be described from Australian waters, especially beyond the soft sediment communities of southeastern Australia which have generated much of the material covered here.
