Definition of agnathan in English:

agnathan

noun & adjective

Zoology
  • See Agnatha

    • ‘Modern vertebrates are classified into two major groups, the gnathostomes (jawed vertebrates) and the agnathans (jawless vertebrates).’
    • ‘One landmark event in vertebrate evolution was the evolution of jaws from agnathan ancestors, which was followed by the first appearance of the stomach.’
    • ‘Although a small number of bony fishes have brains of the same relative size as those in agnathans, most bony fishes have considerably larger brains for the same body size.’
    • ‘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.’