The Sipunculan or peanut worms are a phylum containing around 300 species (2). The peanut worm is commonly referred to as an unsegmented marine worm that is bottom-dwelling and burrows within the mud or sand between tide levels. These worms can be found commonly within seabeds throughout the ocean although considered substantially rare. In respect to physical attributes, the peanut worm body length can range from a few to 500mm. The mouth is usually surrounded by one or more rings of tentacles. The sipunculids utilize external fertilization for reproduction, while as larvae, the organisms maintain a pelagic lifestyle until metamorphosis (1). Although uncommon, sipunculans can reproduce asexually. In addition, some species have the ability to hatch directing into adulthood while others indefinitely have a larval phase (2).
(1) “Peanut worm.” Encyclopedia Britannica, Encyclopedia Britannica, Inc., https://www.britannica.com/animal/peanut-worm.
(2) “Marine Worms- Sipunculid worms or peanut worms.” Marine Education Society of Australasia, MESA, http://www.mesa.edu.au/marine_worms/marine_worms08.asp
- Rocky Intertidal Zone