jawless fish

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Related to jawless fish: coelacanth, cartilaginous fish

jawless fish

Any of various elongated marine and freshwater fishes lacking jaws and paired appendages, sometimes thought to constitute the taxon Agnatha. The only extant jawless fishes are the hagfishes and the lampreys.

American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

jaw′less fish`

1. Also called cyclostome. any fish of the class Agnatha (and order Cyclostomata), characterized by a circular sucking mouth that lacks jaws.

2. ostracoderm.

[1965–70]

jaw·less fish

(jô′lĭs)

Any of several primitive fish that lack a jaw and resemble the eels. Jawless fish include the lampreys and hagfish. Compare bony fish, cartilaginous fish.

The American Heritage® Student Science Dictionary, Second Edition. Copyright © 2014 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

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Noun 1. jawless fish - eel-shaped vertebrate without jaws or paired appendages including the cyclostomes and some extinct formsjawless fish - eel-shaped vertebrate without jaws or paired appendages including the cyclostomes and some extinct forms

agnathan, jawless vertebrate

aquatic vertebrate - animal living wholly or chiefly in or on water

Agnatha, superclass Agnatha - superclass of eel-shaped chordates lacking jaws and pelvic fins: lampreys; hagfishes; some extinct forms

ostracoderm - extinct fish-like jawless vertebrate having a heavily armored body; of the Paleozoic

heterostracan - extinct jawless fish with the anterior part of the body covered with bony plates; of the Silurian and Devonian

cephalaspid, osteostracan - extinct jawless fish of the Devonian with armored head

anaspid - extinct small freshwater jawless fish usually having a heterocercal tail and an armored head; of the Silurian and Devonian

conodont - small (2 inches long) extinct eellike fish with a finned tail and a notochord and having cone-shaped teeth containing cellular bone; late Cambrian to late Triassic; possible predecessor of the cyclostomes

cyclostome - primitive aquatic vertebrate

lamper eel, lamprey, lamprey eel - primitive eellike freshwater or anadromous cyclostome having round sucking mouth with a rasping tongue

hagfish, slime eels - eellike cyclostome having a tongue with horny teeth in a round mouth surrounded by eight tentacles; feeds on dead or trapped fishes by boring into their bodies

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References in periodicals archive ?

It hosts type of jawless fish called lamprey which existed 200 million years before dinosaurs.

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Marine organisms such as sponges and algae, along with primitive snails, clams, cephalopods and jawless fish called ostracoderms, all suffered as a consequence.

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"Instead, our work shows that almost every major vertebrate division, from the earliest armored jawless fish all the way up through sharks and our own ancestors, all started out right near the beach, far inshore of the reef.

Shallows: 'Cradle of Evolution' for Early Fish

Moreover, the cartilaginous fish have five to seven pairs of gills, and primitive jawless fish have seven pairs of gills (Romer, 1949).

Morphological Studies on the Gills of Puffer Fish (Lagocephalus sceleratus, Gmelin, 1789)/Estudios Morfologicos en Branquias del Pez Globo (Lagocephalus sceleratus, Gmelin, 1789)

Material properties of the skins of cartilaginous (e.g., Naresh et al., 1997) and bony fishes (e.g., Hebrank, 1980; Hebrank and Hebrank, 1986; Brainerd, 1994) have been measured; however, data sets from testing on jawless fish skins have yet to be published.

Material properties of hagfish skin, with insights into knotting behaviors

The creature was probably an ancestor of lampreys, jawless fish that can latch onto prey like a vacuum cleaner hose with teeth, say study coauthor Victoria McCoy of Yale University and colleagues.

True nature of 'Tully monster' revealed

The jawless fish (Class Agnatha) are represented with an interesting study with sea lamprey (Petromyzon marinus) describing the relationship between sperm DNA damage and fertilizing ability [110], while cartilaginous fish (Class Chondrichthyes) are completely unexplored.

An introduction about genotoxicology methods as tools for monitoring aquatic ecosystem: present status and future perspectives