The Pliocene Environment and Hominin Diversity 153in other australopithecines and humans, the enamel in
the molar teeth is thick. The limb bone fragments indi-
cate bipedalism.
Moving closer to the present, the next species de-
fined in the fossil record is Australopithecus afarensis.Species Location Dates Notable Features/Fossil Specimens
Ardipithecus
ramidusEthiopia 4.4 mya† Fossil remains of over thirty-five individuals including Ardi (another
species, Ardipithecus kadabba, dates to 5.4–5.8 mya)
A. anamensis Kenya 3.9–4.2 mya Oldest australopithecine
Kenyanthropus platyops Kenya 3.2–3.5 mya Contemporary with australopithecines, believed by some to be a
member of that genus
A. africanus South Africa 2.3–3 mya First discovered, gracile, well represented in fossil record (Taung)
A. aethiopicus Kenya 2.5 mya Oldest robust australopithecine (Black Skull)
A. bahrelghazali Chad 3–3.5 mya Only australopithecine from Central Africa
A. boisei Kenya 1.2–2.3 mya Later robust form coexisted with early Homo (Zinj)
A. garhi Ethiopia 2.5 mya Later East African australopithecine with humanlike dentition
A. robustus South Africa 1–2 mya Coexisted with early Homo*Paleoanthropologists differ in the number of species they recognize, some suggesting separate genera.
†Million years ago.Table 7.1 Species of Australopithecus and Other Pliocene Fossil Hominins*Lucy, the 3.2-million-year-old fossil specimen, is on
a six-year U.S. tour as part of a traveling exhibit orga-
nized and curated by the Ethiopian government and
the Houston Museum of Natural History. Though Lucy
has done much to popularize paleoanthropology and
evolutionary studies since her discovery in 1974, some
paleoanthropologists—like C. Owen Lovejoy and Rich-
ard Leakey—have said that placing her fragile ancient
skeleton on public display is far too risky. The Smithso-
nian Institution and the Cleveland Museum of Natural
History have declined to host the show for this reason.
Others—like her discoverer Donald Johanson, pictured
here with Lucy in the exhibition space in Times Square,
New York—feel that the benefits outweigh the risks.
Benefits include the study of Lucy’s remains via CT
scans so that future generations of scientists can study
them without actually handling the fragile bones. In
addition, the revenues from the tour will be used to
help modernize Ethiopia’s museums. Finally, the ex-
hibit will increase public awareness of human origins
and the vital role of Africa and, in particular, Ethiopia
in our evolutionary history.© AP Photo/Richard Drew
No longer the earliest australopithecine species, it still
remains one of the best known due to the Laetoli foot-
prints from Tanzania, the famous Lucy specimen, and
the recent discovery of the 3.3-million-year-old remains
of a young child called “Lucy’s baby,” both from Ethiopia.