Petromyzontidae

Petromyzontidae are a family of lampreys native to the Northern Hemisphere, comprising the vast majority of living lampreys. Petromyzontids have the highest number of chromosomes (164–174) among vertebrates.

species of chordates

species of chordate

Ichthyomyzon is a genus of lampreys in the family Petromyzontidae, native to North America.

species of chordates

species of lamprey

species of chordates

Entosphenus is a genus of lampreys.

species of chordates

species of chordates

Caspiomyzon is a genus of lamprey in the family Petromyzontidae. They are native to Eastern Europe and parts of Western and Central Asia. Two of the three species in the genus are endemic to Greece.

Tetrapleurodon is a genus of lampreys that are endemic to the Lerma–Chapala basin in west–central Mexico. Both species are threatened.

species of chordates