Sipunculans are a phylum of marine worms found throughout the world's oceans. There have been 320 species of Sipuncula described worldwide, with 27 species confirmed in the Gulf of Mexico. Sipunculans are found in all marine habitats, from shallow, intertidal pools to the deep ocean.
Sipunculans burrow into sandy or muddy bottoms, live under rocks, and can also be found in crevices, coral, seaweed roots, and algal mats.
Sipunculans range in size from 2 to 400 millimeters. They are distinguished from other marine worms by their entirely unsegmented body. The body cavity is fluid-filled and comprised of free floating cell clusters which transport nutrients throughout the body. Sipunculans have a retractable mouth, and lack a circulatory or respiratory system.
(Information from
Gulf of Mexico Origin, Waters, and Biota: Volume 1, Biodiversity,
Texas A&M University Press 2009).
