Many fish have tooth-like structures on bones derived from gill supports and use these teeth to process foods. The teeth themselves vary according to function. The first set
of pictures below show the pharyngeal teeth of a fish (possibly a parrotfish) specialized for grinding. The second set shows a more generalized type.
Carp and many other kinds of fish have pharyngeal jaws, specialized bony plates in the throat that bear teeth. Two views of such a jaw are shown above (the species represented is unknown, but probably is marine).
Two views of a fossil pharyngeal jaw and teeth from Eddy County, NM, probably originating in the Pecos River. Age is late Pleistocene (ca. 15 - 20 thousand years old).