A fossil stapes from Sterkfontein, South Africa, and the hearing capabilities of early hominids.

The three small bones of the human middle ear—the malleus, incus and stapes—have been the subject of research since the mid fifteenth century (Arensburg et al., 1981). Consequently, knowledge of their anatomy and embryology is extensive (e.g. Schuknecht & Gulya, 1986; McPhee & Van de Water, 1988). Middle ear bones have also been well studied in other extant primates and in Neanderthals (e.g., Masali & Chiarelli, 1965a,b; Masali, 1968; Arensburg & Nathan, 1972; Hershkovitz, 1977; Heim, 1982; Arensburg & Tillier, 1983; MacPhee & Cartmill, 1986; Masali et al., 1991; Arensburg et al., 1996). However, relatively little is known about the middle ear bones of early hominids. Hitherto, the only PlioPleistocene hominid ear ossicle described is an incomplete incus recovered from the temporal bone of a specimen assigned to Australopithecus robustus (SK 848) from Swartkrans, South Africa (Rak & Clarke, 1979a,b; Rak, 1994). In this paper, we describe a second early hominid middle ear bone, a stapes, which was recently found in association with a specimen from Sterkfontein, South Africa. We also outline