Evolution And History

158 CHAPTER 7 | The First Bipeds

To further complicate the diversity seen in A. afarensis,

in 2001 Meave and Louise Leakey announced the discovery

of an almost complete cranium, parts of two upper jaws,

and assorted teeth from a site in northern Kenya, dated to

between 3.2 and 3.5 mya.^5 Contemporary with early East

African Australopithecus, the Leakeys see this as a different

genus named Kenyanthropus platyops (“flat-faced man of

Kenya”). Unlike early australopithecines, Kenyanthropus

is said to have a small braincase and small molars set in a

large, humanlike, flat face. But again, there is controversy;

the Leakeys see the fossils as ancestral to the genus Homo.

Other paleoanthropologists are not convinced, suggest-

ing that the Leakeys’ interpretation rests on a questionable

reconstruction of badly broken fossil specimens.^6

Central Africa

Dated to the same time period as Kenyanthropus platyops

is another recent discovery of an australopithecine from

Chad in Central Africa. The name of the new species,

Australopithecus bahrelghazali, is for a nearby riverbed and

This 3- to 4-million-year-old skull could be another australopithecine or,

as its discoverers suggest, a separate genus: Kenyanthropus platyops.

© Dr. Fred Spoor/National Museums of Kenya

Present

surface

Reconstructed

surface

Catchment

area

Limestone

20

0

Feet

40

Reconstructed

rock overhang

and shaft

Figure 7.9 Many of the fossil sites in South Africa were

limestone caverns connected to the surface by a shaft. Over

time, dirt, bones, and other matter that fell down the shaft

accumulated inside the cavern, becoming fossilized. In the

Pliocene, the earth next to the shaft’s opening provided a

sheltered location for trees that, in turn, may have been used

by predators for eating without being bothered by scavengers.

consists of a jaw and several teeth dated to between 3 and

3.5 mya.^7 This is the first australopithecine discovered in

Central Africa. With time, perhaps more discoveries from

this region will give a fuller understanding of the role of A.

bahrelghazali in human evolution and its relationship to

the possible bipeds from the Miocene.

South Africa

Throughout the 20th century and into the present,

paleoanthropologists have continued to recover australo-

pithecine fossils from a variety of sites in South Africa.

Included in this group are numerous fossils found begin-

ning in the 1930s at Sterkfontein and Makapansgat, in

addition to Dart’s original find from Taung.

It is important to note, however, that South African

sites, lacking the clear stratigraphy and volcanic ash of East

African sites, are much more difficult to date and interpret

(Figure 7.9). One unusually complete skull and skeleton

has been dated by paleomagnetism to about 3.5 mya,^8

(^7) Brunet, M., et al. (1995).The first australopithecine 2,500 kilome ters west
of the Rift Valley (Chad). Nature 16, 378 (6554), 273–275.
(^8) Clarke, R. J. (1998). First ever discovery of a well preserved skull and associ-
ated skeleton of Australopithecus. South African Journal of Science 94, 460–464.
Kenyanthropus platyops A proposed genus and species of
biped contemporary with early australopithecines; may not be a
separate genus.
(^5) Leakey, M. G., et al. (2001). New hominin genus from eastern Af rica
shows diverse middle Pliocene lineages. Nature 410, 433–440.
(^6) White, T. D. (2003). Early hominids—diversity or distortion? Sci ence 299,
1994–1997.