Petromyzontidae

{{Short description|Family of lampreys}}

{{Automatic taxobox

| image = Sea Lamprey fish.jpg

| image2 = Petromyzon marinus2.jpg

| image_caption = Sea lampreys (Petromyzon marinus) on a lake trout

| taxon = Petromyzontidae

| authority = A. Risso, 1827

| type_species = Petromyzon marinus

| type_species_authority = Linnaeus, 1758

| subdivision_ranks = Genera

| subdivision =

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.{{cite book |last1=McEachran |first1=J. |last2=Fechhelm |first2=J.D. |title=Fishes of the Gulf of Mexico, Vol. 1: Myxiniformes to Gasterosteiformes |publisher=University of Texas Press |publication-place=Austin |year=1998 |isbn=978-0-292-75206-1 |oclc=38468784 |url=https://books.google.com/books?id=lAgyDQAAQBAJ |access-date=12 July 2021 |page=35}} Petromyzontids have the highest number of chromosomes (164–174) among vertebrates.{{FishBase family |family=Petromyzontidae |month=February |year=2011}}