[organisms] see Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
   Pisces
     Class Agnatha Cope, 1889
       Order Petromyzontiformes Berg, 1940 - lampreys
         Family Petromyzontidae Bonaparte, 1832 - lampreys
           1 Genus Lampetra Bonnaterre, 1788
           2 Genus Lethenteron Creaser & Hubbs, 1922
           3 Genus Petromyzon Linnaeus, 1758