gnath·o·stome 
(năthə-stōm′)
(năthə-stōm′)n.
Any of numerous animals of the group Gnathostomata, consisting of all vertebrates with jaws and including the mammals, birds, reptiles, amphibians, and fishes except for lampreys and hagfishes.
[From New Latin Gnathostomata, taxon name : Greek gnathos, jaw; see genu-2 in the Appendix of Indo-European roots + Greek stoma, stomat-, mouth.]
gnatho·stome′ adj.