Gnathifera is an assemblage of phyla of platyzoans comprising the rotifers (Bdelloidea, Monogononta, Seisonidae), acanthocephalans, and gnathostomulids. Also included is the Micrognathozoa, and tentatively the Cycliophora.
"Acanthognatha" is a similar grouping, with the addition of the gastrotrichs.
Possible relationships are as in the cladogram: