noun
- A jawless fish with a circular mouth, such as a lamprey or hagfish; a member of the class Petromyzontida or Cephalaspidomorphi.
Usage: zoology; technical
Examples
- The lamprey is a cyclostome that attaches to other fish using its sucker-like mouth.
- Cyclostomes are among the most ancient vertebrates, with fossils dating back hundreds of millions of years.
- Unlike most fish, cyclostomes lack jaws and scales.
- The hagfish, another cyclostome, is known for producing slime as a defense mechanism.
- Marine biologists study cyclostomes to understand early vertebrate evolution.