lamprey

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lamprey,

name for several primitive marine and freshwater jawless fishes of the order Petromyzontiformes. As in the other jawless fish, the hagfishhagfish,
primitive, jawless marine fish of the family Myxinidae, of worldwide distribution in cold and temperate waters. Its rudimentary skeleton, of cartilage rather than bone, has a braincase, but no jaw. The circular sucking mouth has rows of horny teeth.
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, the adult lamprey retains the notochordnotochord
, in biology, supporting rod running most of the length of animals of the phylum Chordata and present at varying times in the life cycle. Composed of large cells packed within a firm connective tissue sheath, the notochord lies between the neural tube (spinal cord) and
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, the supporting structure that in higher vertebrates is found only in the embryo. An ancient fish that still resembles fossils that are 360 million years old, the lamprey lacks a sympathetic nervous system, a spleen, and scales.

The adult lampreys of some species are parasitic, sucking the blood of other fishes. The horny teeth, set in the circular, jawless mouth, attach to the prey and the lamprey feeds as it is carried along. Lampreys have an anticoagulant in the saliva that keeps the blood of the victim fluid. The parasitic sea, or Atlantic, lamprey, Petromyzon marinus, found on both sides of the Atlantic, has become well established in the Great Lakes, where it is considered a serious pest by the fishing industry. Many freshwater lampreys are not parasitic.

Lampreys resemble eelseel,
common name for any fish in the order Anguilliformes, and characterized by a long snakelike body covered with minute scales embedded in the skin. Eels lack the hind pair of fins, adapting them for wriggling in the mud and through the crevices of reefs and rocky shores.
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 in external appearance and, although not related to the true eels, are sometimes called lamprey eels. When not attached to prey, they swim with undulating movements. The marine lampreys normally migrate into freshwater to spawn, and some populations have become landlocked in freshwater.

The sexes are separate in lampreys and fertilization is external. The parents die shortly after the eggs are deposited in a nest. The larvae, called ammocoetes, are about 1-4 in. (6 mm) long. They are transparent, eyeless filter-feeders and live in muddy river bottoms, eating particles of organic matter. Ammocoetes are used in zoology courses to demonstrate a theoretically primitive vertebrate construction. At about five years of age they metamorphose into the adult form. In some species the adult does not feed and remains the size of the larva.

Lampreys are classified in the phylum ChordataChordata
, phylum of animals having a notochord, or dorsal stiffening rod, as the chief internal skeletal support at some stage of their development. Most chordates are vertebrates (animals with backbones), but the phylum also includes some small marine invertebrate animals.
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, subphylum Vertebrata, class Hyperoartia, order Petromyzontiformes.

lamprey

[′lam·prē]
(vertebrate zoology)
The common name for all members of the order Petromyzonida.

lamprey

any eel-like cyclostome vertebrate of the family Petromyzonidae, having a round sucking mouth for clinging to and feeding on the blood of other animals
References in periodicals archive ?
Although there is considerable effort underway to understand the habitat requirements of lampreys in freshwater (e.
This means that we can use the sea lamprey as a powerful model to drive forward our molecular understanding of human neurodegenerative disease and neurological disorders," said Jennifer Morgan of the MBL's Eugene Bell Center for Regenerative Biology and Tissue Engineering.
A biopsy was performed on the tumor, and Lamprey was diagnosed with Stage 4 brain cancer.
University of British Columbia Professor David Close has discovered a steroid hormone in the Pacific lamprey that may help in the conservation of this eel-like fish, which dates back 500 million years and is culturally important to the tribes of the Columbia River.
Additional knowledge about stress in lampreys will help in solving the problems presented by both species.
Symposium on Biology and Conservation of Lampreys in North America (2007: San Francisco, CA) Ed.
Paul Frear, Environment Agency fisheries officer, said: "We were thrilled to discover lampreys back in the River Wear, as these rare blood-suckers show us that the water quality in the river is very high.
I'll eat anything" card, Strictly Come Dancing judge Craig Revel Horwood reacts to lamprey blood sauce in the way you'd expect of a man in a sequinned tie.
Lampreys are thought to have been on the planet for 300 million years and, like the salmon and sewin, they are anadromous - spawning in fresh water and spending much of their time at sea.
Sea lampreys spend an extended larval stage of up to 20 years in freshwater streams and then migrate to a larger body of water.
Aquatic nuisance species such as the zebra mussel, sea lamprey, ruffe and goby not only threaten the Great Lakes, but also pose a significant economic threat to the State of Michigan.
Variable effects of goitrogens in inducing precocious metamorphosis in sea lampreys (Petromyzon marinus).