单词 | jawless vertebrate |
释义 | jawless vertebrate (extremely rare) n WORD FAMILY jawless vertebrate n eel-shaped vertebrate without jaws or paired appendages including the cyclostomes and some extinct forms Syn|Hypo|Hyper agnathan, jawless fish ostracoderm extinct fish-like jawless vertebrate having a heavily armored body; of the Paleozoic heterostracanextinct jawless fish with the anterior part of the body covered with bony plates; of the Silurian and Devonian cephalaspid, osteostracanextinct jawless fish of the Devonian with armored head anaspidextinct small freshwater jawless fish usually having a heterocercal tail and an armored head; of the Silurian and Devonian conodontsmall (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 cyclostomeprimitive aquatic vertebrate lamper eel, lamprey, lamprey eelprimitive eellike freshwater or anadromous cyclostome having round sucking mouth with a rasping tongue hag, hagfish, slime eelseellike 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 Petromyzon marinus, sea lampreylarge anadromous lamprey sometimes used as food; destructive of native fish fauna in the Great Lakes Myxine glutinosatypical hagfish eptatretusa fossil hagfish of the genus Eptatretus Myxinikela sirokafossil hagfish of the Pennsylvanian period (c. 300 million years ago) that resembled modern hagfishes aquatic vertebrate animal living wholly or chiefly in or on water |
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