hagfish

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Related to hagfishes: chimaeras, Ostracoderms

hagfish,

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. There is a single median nostril and the eyes are poorly developed. Like the other jawless fishes, the lampreyslamprey,
name for several primitive marine and freshwater jawless fishes of the order Petromyzontiformes. As in the other jawless fish, the hagfish, the adult lamprey retains the notochord, the supporting structure that in higher vertebrates is found only in the embryo.
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, hagfish retain 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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, a supporting structure found in higher vertebrates only in the embryo, throughout life. They lack a sympathetic nervous system, a spleen, and scales. Hagfish, or hags, spend much time embedded in muddy bottoms. They are chiefly scavengers, but also parasitize slow-moving fishes, eating their way into the victim's body and leaving only the skin and skeleton. Also known as slime eels, hagfish have glands on either side of their bodies that produce enormous quantities of mucoid material, probably as a defense mechanism. The sexes are separate, although an individual may have rudimentary organs of the opposite sex. Spawning occurs throughout the year; no larval stage is known. The Atlantic hagfish, Myxine glutinosa, may reach a length of 30 in. (76 cm). The Pacific hagfish, Eptatretus stouti, has been extensively used in physiological studies. The hagfish is 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 Myxini, order Myxiniformes, family Myxinidae.

hagfish

[′hag‚fish]
(vertebrate zoology)
The common name for the jawless fishes composing the order Myxinoidea.
References in periodicals archive ?
Since it is the skin that interfaces with the aquatic medium, the absence of myoseptal-skin connections in hagfishes likely results in an indirect and reduced transmission of muscle-generated force to the skin and, ultimately, to the water (Vogel and Gemballa, 2000).
Given the extraordinary axial morphology and movements of hagfishes, the probable but unresolved functional link between fish integument and locomotion, and the overall paucity of data, the skins of myxinid fishes make a fascinating and convenient system for investigating morphological and mechanical characteristics associated with whole-body knotting movements.
Hagfishes would certainly benefit from possessing puncture-resistant skin, as they lack dermal scales and occasionally encounter predators.
Wild specimens of hagfishes have been recorded avoiding predatory attacks by ram-feeding fishes, like seal sharks and conger eels, and suction-feeding fishes, such as scorpionfishes and wreckfishes (Zintzen et al.
This is in agreement with Mok (2001), who suggested that the common ancestor of hagfishes could have had these papillae.
Western Atlantic hagfishes of the genus Eptatretus (Myxinidae) with description of two new species.
Three new species of seven-gilled hagfishes (Myxinidae, Eptatretus) from the Pacific Ocean.
Review of the hagfishes (Myxinidae, Myxiniformes) of the northwestern Pacific Ocean, with descriptions of three new species, Eptatretus fernholmi, Paramyxine moki, and P.
Hagfishes and spotted ratfish were significantly greater in abundance and activity during the night (P<0.
Rosethorn rockfish and hagfishes exhibited distinct diurnal and nocturnal activity, respectively.
The nocturnal activity pattern that hagfishes exhibited was similar to that observed by Ooka-Souda et al.
uariegatus) spotted ratfish (Hydrolagus colhei) unidentified hagfishes (Eptatretus spp.