''Cerebratulus lacteus'', the milky nemertean or milky ribbon worm, 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 a wide geographical range on both sides of the northern Atlantic Ocean.

Description

''Cerebratulus lacteus'' grows to a length of about and a width of . The head is rounded and flattened, with a pair of cerebral organs and cephalic grooves, but no eyes. The head is not readily distinguishable from the body, which is flattened and gradually tapers towards the tail, where there is a slender caudal cirrus. This worm is usually milky-white in colour but may be pink.

Ecology

''Cerebratulus lacteus'' burrows in muddy sediments into which it can burrow rapidly. It is a voracious

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 ...

and has been observed attacking

bivalve molluscs Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, bival ...

and crustaceans. The

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 ...

is everted (turned inside out) and the lower half of the

Atlantic jackknife clam The Atlantic jackknife clam, ''Ensis leei'', also known as the bamboo clam, American jackknife clam or razor clam, is a large edible marine bivalve mollusc found on the North American Atlantic coast, from Canada to South Carolina. The species ...

(''Ensis directus'') is enveloped. In an effort to escape, the clam works its way out of the sediment and may then be at risk of predation by birds. Soft clams, such as '' Mya arenaria'' are also attacked. In this case, the ribbonworm inserts the tip of its proboscis through the

siphon A siphon (from grc, σίφων, síphōn, "pipe, tube", also spelled nonetymologically syphon) is any of a wide variety of devices that involve the flow of liquids through tubes. In a narrower sense, the word refers particularly to a tube in a ...

and consumes the soft tissues. It is not clear whether the ribbonworm preys on hard clams, but a high abundance of this worm at one location near

Prince Edward Island Prince Edward Island (PEI; ) is one of the thirteen Provinces and territories of Canada, provinces and territories of Canada. It is the smallest province in terms of land area and population, but the most densely populated. The island has seve ...

was thought to be responsible for the high mortality among newly transplanted hard clams. As is the case with other nemertean worms, the sexes are separate in this species and fertilisation is external. Reproduction can also occur by

fragmentation Fragmentation or fragmented may refer to: Computers * Fragmentation (computing), a phenomenon of computer storage * File system fragmentation, the tendency of a file system to lay out the contents of files non-continuously * Fragmented distributi ...

, as this worm readily breaks into pieces which can grow into new organisms.

Research

''Cerebratulus lacteus'' produces several homologous

polypeptide Peptides (, ) are short chains of amino acids linked by peptide bonds. Long chains of amino acids are called proteins. Chains of fewer than twenty amino acids are called oligopeptides, and include dipeptides, tripeptides, and tetrapeptides. A p ...

cytotoxins that are active in breaking down the membranes of human

red blood cells Red blood cells (RBCs), also referred to as red cells, red blood corpuscles (in humans or other animals not having nucleus in red blood cells), haematids, erythroid cells or erythrocytes (from Greek language, Greek ''erythros'' for "red" and ''k ...

, as well as several

neurotoxin Neurotoxins are toxins that are destructive to nerve tissue (causing neurotoxicity). Neurotoxins are an extensive class of exogenous chemical neurological insultsSpencer 2000 that can adversely affect function in both developing and mature ner ...

s. These substances are being researched. Clams have been identified as a useful subject for

aquaculture Aquaculture (less commonly spelled aquiculture), also known as aquafarming, is the controlled cultivation ("farming") of aquatic organisms such as fish, crustaceans, mollusks, algae and other organisms of value such as aquatic plants (e.g. lot ...

in Canada. Because ''Cerebratulus lacteus'' is a threat to such activities, research is ongoing into the ribbonworm and what governs its patchy distribution, with a view to being able to better control it.

References

{{Taxonbar, from=Q1867560 Lineidae Animals described in 1851