jawless fish

jawless fish

n.

Any of several eellike marine and freshwater fishes lacking a jaw and paired appendages that constitute the subphylum Agnatha. The only present-day jawless fish are the hagfish and lampreys.

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jawless fish  (jôls)

Any of various primitive fish of the class Agnatha that lack jaws. Living jawless fish (lampreys and hagfish) have a long, cylindrical body and a cartilaginous skeleton. The numerous extinct species were often heavily armored and are among the earliest vertebrate fossils known. Jawless fish occupy an intermediate evolutionary position between primitive chordates and jawed fish. Also called agnathan. See more at cyclostome. Compare bony fishcartilaginous fish

Thesaurus

Noun

1.

jawless 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, hag - 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