Petromyzontidae

Petromyzontidae
Sea lampreys (Petromyzon marinus) on a lake trout
Scientific classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebrata
Infraphylum: Agnatha
Superclass: Cyclostomi
Class: Petromyzontida
Order: Petromyzontiformes
Family: Petromyzontidae
A. Risso, 1827
Type species
Petromyzon marinus
Genera

Caspiomyzon
Entosphenus
Eudontomyzon
Ichthyomyzon
Lampetra
Lethenteron
Petromyzon
Tetrapleurodon

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.