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agnathan

noun
ag·​na·​than | \ˈag-nə-thən \
plural agnathans

Definition of agnathan 

: jawless fish Two jawless fishes (agnathans) are recognized in these fossils … based on differences in the shape and histology of their tubercles …— Moya Meredith Smith, Science, 18 Jan. 1991

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First Known Use of agnathan

1939, in the meaning defined above

History and Etymology for agnathan

agnatha + -an entry 1

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The first known use of agnathan was in 1939

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