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.

[1] Petromyzontids have the highest number of chromosomes (164–174) among vertebrates.

[2]

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