Ryan Photographic - Spionidae - Mud worms, palm worms
The family Spionidae contains around 450 species in 38 genera. They are widely distributed in the world's oceans and some are also found in freshwater or brackish environments.
Spionids secrete a mucus tube which they reinforce with sand grains and detrital material. Some tubes are buried in mud while other spionid species burrow into living bivalve shells, dead coral or limestone rock (presumably producing acid to do so). Many spionids, like the species in the photo below, lie prone across the substrate.
With the exception of the genus Scolelepis, spionids feed by virtue of extensible ciliated palps which utilise cilia to transport food back to the mouth. Scolelepis lacks the ciliated groove and food is brought back to the mouth by retraction of the palps. While most species are deposit feeders, a few are capable of both suspension and deposit feeding.
Their mode of reproduction varies widely with species: some can reproduce asexually while others produce large eggs which may be protected in their burrow before release into the water column. In a few species the larvae feed on other eggs within the egg sac.
Shell boring spionids may cause problems for commercial bivalve production by causing blisters between the shell and the mantle of their host.
Polydorella prolifera Spionid worms,
Polydorella prolifera Spionid worms, Raja Ampat, West Papua IMG_2734
Polydorella prolifera Spionid worms, Raja Ampat, West Papua IMG_2735