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Petromyzontida

Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025

Definition

Petromyzontida, commonly known as lampreys, are jawless vertebrates characterized by their elongated, eel-like bodies and circular, sucker-like mouths. They are often parasitic, feeding on the blood and bodily fluids of other fish.

5 Must Know Facts For Your Next Test

  1. Lampreys belong to the superclass Agnatha, which includes all jawless fish.
  2. They have cartilaginous skeletons instead of bony ones.
  3. Petromyzontida exhibit an anadromous life cycle, typically migrating from saltwater to freshwater to spawn.
  4. Their mouths contain keratinized teeth used for attaching to host fish and feeding.
  5. Unlike many other vertebrates, lampreys lack paired fins and scales.

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