Agnathans
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What are Agnathans? The term agnatha means “no jaw,” and this group includes a wide variety of jawless fishes. Most extinct agnathans had thick bodies, paired fins, and body armor of some kind. Living agnathans, the lampreys, have elongated bodies, and lack body armor and paired fins. Agnathans arose in the Cambrian and were at their highest diversity during the Early to Middle Paleozoic. Note: While often grouped with agnathans, hagfish are more closely related to other chordates and are discussed in Hemichordates and Chordates. First known fossil occurrence: Cambrian. Last known fossil occurrence: Quaternary. This group has living relatives. Cool Agnathans links: Search for images of Agnathans on Google |
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