less, extant vertebrates.
The lampreys, in addition to lacking the jaws seen with other fish, also lack paired . They are otherwise known as .
Contrast lampreys also with hagfish, which unlike lamprey lack , though for hagfish that may be a derived condition. Indeed, are suggestive that the lamprey and hagfish together form a clade that is separate from that of the rest of subphylum Vertebrata. Nevertheless, a jawless vertebrate likely serves as the ancestor to all three taxa (hagfish, lamprey, and vertebrates).
Contrast lampreys and, indeed, agnathans with gnathostomes.