168 CHAPTER 7 | The First Bipeds
However, the large teeth and face of
this specimen resemble the earlier
australopithecines.
From this same site
another well-preserved
skull from the same time
period (KNM ER 1813)
possesses a cranial capac-
ity of less than 600 cc but
has the derived charac-
teristics of a smaller, less
projecting face and teeth
(both of these specimens
are shown in the photo
on page 160). Though specimens attributed to H. habilis
generally have cranial capacities greater than 600 cc, the
cranial capacity of any individual is also in proportion to its
body size. Therefore, many paleoanthropologists interpret
KNM ER 1813 and ER 1470 as a female and male of a very
sexually dimorphic species, with the smaller cranial capac-
ity of KNM ER 1813 a reflection of her smaller body size
(Figure 7.18).Lumpers or Splitters?
Other paleoanthropologists do not agree with placing
specimens as diverse as KNM ER 1813 and KNM ER 1470
in the single taxonomic group of H. habilis. Instead they
feel that the diversity represented in these specimens war-
rants separating the fossils like the larger-brained KNM
ER 1470 into a distinct coexisting group called HomoH. habilis as well. Since the late 1960s, fossils of the genus
Homo that are essentially contemporaneous with those
from Olduvai have been found elsewhere in Africa, such
as South Africa, Ethiopia, and several sites in Kenya.
The eastern shores of Lake Turkana, on the border be-
tween Kenya and Ethiopia, have been particularly rich with
fossils from earliest Homo. One of the best of these fossils,
known as KNM ER 1470, was discovered by the Leakeys’
son Richard at Koobi Fora. (The letters KNM stand for
Kenya National Museum; the ER, for East Rudolf, the
name for Lake Turkana during the colonial era in Kenya.)
The deposits in which it was found are about 1.9 million
years old; these deposits, like those at Olduvai, also con-
tain crude stone tools. The KNM ER 1470 skull is more
modern in appearance than any Australopithecus skull
and has a cranial capacity of 752 cubic centimeters (cc).
Juvenile gorilla Olduvai hominin Modern humanFigure 7.16 A comparison of hand bones of a juvenile gorilla,
Homo habilis from Olduvai, and a modern human, highlights
important differences in the structure of fingers and thumbs.
In the top row are fingers, and in the second row are terminal
(end) thumb bones. Although terminal finger bones are more
human, lower finger bones are more curved and powerful. The
bottom row compares thumb length and angle relative to the
index finger.
Figure 7.17 A partial foot skeleton of Homo habilis (center)
is compared with the same bones of a chimpanzee (left) and
modern human (right). Note how H. habilis’ bone at the base of
the great toe is in line with the others, as in modern humans,
making for effective walking but poor grasping.Lake
Turkana
UGANDA KENYASUDAN R ETHIOPIAiverOmoKoobi Fora
(East Turkana)