''Cerebratulus marginatus'' is a proboscis worm in the family

Lineidae Lineidae is a family of nemertean worms. It contains the following genera: * '' Aetheolineus'' Senz, 1993 * '' Ammolineus'' Senz, 2001 * ''Antarctolineus'' Muller & Scripcariu, 1964 * ''Apatronemertes'' Wilfert & Gibson, 1974 * '' Australineus'' ...

. This ribbon worm has an Arctic distribution, and in the North Atlantic Ocean ranges as far south as

Cape Cod Cape Cod is a peninsula extending into the Atlantic Ocean from the southeastern corner of mainland Massachusetts, in the northeastern United States. Its historic, maritime character and ample beaches attract heavy tourism during the summer mont ...

and the

Mediterranean Sea The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the ea ...

while in the Pacific Ocean it extends southwards to California.

Description

''Cerebratulus marginatus'' is a long, flattened worm that when fully extended grows to a length of over a metre (yard), but can contract to less than half its full length. Its width can be around . The head tapers to a blunt point and the cephalic furrows are wide. The eyes contain dark pigment and are tiny and difficult to distinguish. Behind the mouth the body becomes dorso-ventrally flattened and often has wrinkles and folds which gives the worm its convoluted appearance. At the end of the body is a slender transparent caudal cirrus. The colour of this worm is somewhat variable; it is usually greyish-brown with pale or transparent edges, but the dorsal surface in older individuals is often darker than the ventral surface; other individuals are slate blue, dark brown or greyish-green. The pinkish nerve cords are often visible through the pale edges of the worm, and in young individuals the cerebral ganglia and the folded

proboscis A proboscis () is an elongated appendage from the head of an animal, either a vertebrate or an invertebrate. In invertebrates, the term usually refers to tubular mouthparts used for feeding and sucking. In vertebrates, a proboscis is an elong ...

may also be discernible through the skin.

Distribution and habitat

''Cerebratulus marginatus'' is native to the northern hemisphere, occurring in the Arctic and the North Atlantic Ocean, as far south as the

in the east and

in the west. In the Pacific Ocean it occurs between

Alaska Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U.S., ...

and

San Diego, California San Diego ( , ; ) is a city on the Pacific Ocean coast of Southern California located immediately adjacent to the Mexico–United States border. With a 2020 population of 1,386,932, it is the eighth most populous city in the United States ...

, and in Japan. It occurs buried in soft sediment in the

littoral zone The littoral zone or nearshore is the part of a sea, lake, or river that is close to the shore. In coastal ecology, the littoral zone includes the intertidal zone extending from the high water mark (which is rarely inundated), to coastal areas ...

but is more common in the

sublittoral zone The neritic zone (or sublittoral zone) is the relatively shallow part of the ocean above the drop-off of the continental shelf, approximately in depth. From the point of view of marine biology it forms a relatively stable and well-illuminated ...

at depths of .

Biology

Like other ribbon worms, ''C. marginatus'' is a

predator Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill th ...

. The proboscis is able to be turned inside out to grasp prey and the diet consists of such invertebrates as clams and

polychaete worms Polychaeta () is a paraphyletic class of generally marine annelid worms, commonly called bristle worms or polychaetes (). Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called chaetae, which are m ...

. As well as burrowing, it can swim well, undulating its body up and down, and sometimes rotating as it does so. As it travels it often lifts its head above the surface of the water. It may be brought to the surface in sediment dredged up from the seabed and has a habit of disintegrating if it is handled. It is sometimes caught with rod and line using live

mussel Mussel () is the common name used for members of several families of bivalve molluscs, from saltwater and Freshwater bivalve, freshwater habitats. These groups have in common a shell whose outline is elongated and asymmetrical compared with other ...

s as bait. The sexes are separate and breeding takes place in summer. The larvae have been used in embryological research.

References

{{Taxonbar, from=Q1980258 Lineidae Animals described in 1804