Petromyzontiformes

order of vertebrates, the lampreys lamprey (Petromyzontiformes) is an order comprising closely related families of organisms. It contains 3 families with 35 known species. This includes the family groups Geotriidae, Mordaciidae, and Petromyzontidae. Among its members, 10 species are currently classified as threatened (Critically Endangered, Endangered, or Vulnerable). It belongs to Petromyzonti (Petromyzonti).