Definition of Agnatha in English:


Line breaks: Ag|natha
Pronunciation: /agˈneɪθə


  • A group of primitive jawless vertebrates which includes the lampreys, hagfishes, and many fossil fishlike forms. Compare with cyclostome.
    • Superclass Agnatha: the living forms are in the classes Myxini (hagfishes) and Cephalaspidomorphi (lampreys)
    More example sentences
    • Here, we use the sequences of 35 nuclear protein-encoding genes to provide definitive evidence for the monophyly of the Agnatha (jawless vertebrates, a group encompassing the hagfishes and lampreys).
    • The earliest fossil vertebrates belong to a group called the Agnatha or jawless vertebrates.
    • In modern classification schemes, living vertebrates consist of two main groups, the jawless Agnatha (represented by hagfishes and lampreys) and the jawed Gnathostomata.



noun & adjective
More example sentences
  • Modern vertebrates are classified into two major groups, the gnathostomes (jawed vertebrates) and the agnathans (jawless vertebrates).
  • Above all, the appearance of diverse chordates and agnathans greatly expands our knowledge of the Cambrian explosion.
  • Sufficient articulated material exists to show that these animals were agnathans (jawless vertebrates), with a bony exoskeleton, and they appear to have inhabited shallow-marine environments.


from modern Latin Agnatha, from a-1 'without' + Greek gnathos 'jaw'.

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