jawless fish

American  

noun

1. cyclostome.

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jawless fish Scientific  

/ jô′lĭs /

1. 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.

2. Also called agnathan

3. See more at cyclostome Compare bony fish cartilaginous fish

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Etymology

Origin of jawless fish

First recorded in 1965–70; jaw ¹ + -less

Example Sentences

The divots were created at a time when animals in the seas were taking on a broad array of new forms, building complex ecosystems from plankton to jawless fish to spaceship-like filter feeders.

From Slate • Oct. 21, 2024

While most jawless fish have 5-20 gill arches, jawed fish almost never have more than five.

From Science Daily • Nov. 1, 2023

“But they have a number of features that are very similar to jawless fish, like complex eyes and cartilaginous vertebrae.”

From Scientific American • Apr. 19, 2023

Another paper describes Tujiaaspis vividus, an extinct jawless fish whose name refers to the Tujia people, a minority ethnic group in China.

From Salon • Oct. 1, 2022

A well-preserved jawless fish offers clues to how ancient fins evolved into arms and legs.

From Seattle Times • Sep. 28, 2022