Common Name: Sand Worm
Scientific Name: Hediste diversicolor
Species: H. diversicolor
Also known as the clamworm, they are a group of mostly marine or shore worms of the class Polychaeta. A few species live in fresh water. Other common names include mussel worm, pileworm, and sandworm. But these terms can all refer to any one of a number of other species of the genus Nereis (or indeed to other polychaetes). Ragworms vary in length from 2.5 to 90 cm (1 inch to 3 feet); they are commonly brown, bright red or bright green. Ragworms are perhaps the most highly developed of the annelids. Another scientific name that can be given to the Ragworm would also be Nereis diversicolor. They are segmented worms with four pairs of tentacles and one pair of antennae. Each segment has a pair of bristly, paddle-like appendages that enable them to swim in the water or crawl along the seafloor.
Despite their name, clam worms are common in a variety of benthic habitats, including sand flats, mudflats, shellfish beds, and algal mats. Some species can also be found living among barnacles and encrusting algaeon man-made structures, such as pilings. It is a free-swimming polychaete, scavenging on the bottom of shallow marine waters. Clamworms are an important food source for bottom-feeding fish and crustaceans, though they can protect themselves by secreting a mucus substance that hardens to form a sheath around them. Clam worms feed on algae and other invertebrates that they find by burrowing in the sand or mud. They are also food for bottom feeding fish and crabs. Not much is known about the life cycle of the H. diversicolor, but during lunar phases in the spring and early summer, the clam worm undergoes "heteronenesis". Their parapodia enlarge so they can swim. The clamworms are then capable of releasing eggs and sperm. After they have released their egg or sperm, they die.
What constantly stood out about the Hediste diversicolor was its technique of eating. When feeding, the clam worm extends its proboscis, which contains hook-like jaws to grasp its prey, and then retracts the proboscis to draw the food into its mouth. Very little of this animal existence was known to me so everything that I researched was basically new to me. (They can also be found along the coast as far as Norland. It lives in the tidal zone, or just below, buried in the sand or muddy substrate. Try pulling away some rocks, and its likely to appear.
Author: Justin M.
Photo Credit: http://www.asturnatura.com/Imagenes/Astur/nerdiv.jpg