noun
- jawless fish, including lampreys and hagfish, that lack true jaws and paired fins; the most ancient vertebrates.
Usage: plural of agnathan; scientific/biological term; also called cyclostomes
Examples
- Agnathans were among the first vertebrates to evolve in Earth's oceans.
- Lampreys and hagfish are modern examples of agnathans.
- The fossil record shows that agnathans dominated early marine ecosystems.
- Unlike most fish, agnathans lack true jaws and paired fins.
- Scientists study agnathans to understand the early evolution of vertebrates.