MIDDLE EAR. “One of the best examples of such a major remnant of evolutionary and developmental history involves the mammalian middle ear ossicles (the malleus, incus, and stapes bones), all of which are derived from jaw bones of ancestral reptiles but which now play a key role in hearing by amplifying sounds.”
https://evolution-outreach.springeropen.com/articles/10.1186/s12052-014-0012-5