(including the OH 28 innominate bone) that have
been attributed to Homo erectus (M. Leakey, 1971a).
Above Bed IV lie the Masek (perhaps 1.0 to 0.75 Ma),
Ndutu (maybe 0.75-0.075 Ma) and Naisiusiu
(possibly about 0.02-0.015 Ma) Beds; one partial
mandible from the Masek Beds (OH 23) has also been
referred to Homo erectus. OH 1, a complete modern
human skeleton whose recovery from Bed I1 caused
considerable controversy earlier this century, is a recent
intrusive burial.
ARCHAEOLOGICAL CONTEXT
Stone tool assemblages are known throughout the
Olduvai sequence, and indeed the Gorge has given its
name to the very earliest recognizable stone tools
known. The crude Bed I lithics are thus referred
to the Oldowan tradition, characterized by small
cores/choppers, battered hammerstones, and numer-
ous simple flakes (M. Leakey, 1971b). Low in Bed I1
the Developed Oldowan appears, with fewer chop-
pers and some crude bifaces. In the upper half of Bed
11, in contrast, beginning at about 1.6 or 1.5 Ma,
large numbers of Acheulean handaxes and cleavers
begin to be found, although not at every occupation
site (M. Leakey, 1971b). In Bed 111 utensils are few,
and Bed IV occupation sites are divided between
those containing an apparent derivative of the Devel-
oped Oldowan and those of Acheulean aspect (M.
Leakey, 1971a). Only one Masek site preserves tools,
in the form of large Acheulean handaxes; in the
Ndutu Beds a fully developed Middle Stone Age in-
dustry is found. In Bed I and Bed I1 times hominid
occupation at Olduvai seems to have been concen-
trated along the southeastern margin of the ancient
lake, where several dense accumulations of cut-
mark-bearing mammal bones and lithics have been
identified. Earlier, such sites were regarded as “home
bases” of the early hominids (e.g., Isaac, 1978), and at
one a low stone “windbreak” was identified. However,
more recent interpretations have been considerably
more circumspect (e.g., Isaac, 1983).PREVIOUS DESCRIPTIONS AND ANALYSES
The Bed I OH 7 individual (mandible, cranial parts and
hand bones) was made the holotype of Homo habilis by
Leakey, Tobias and Napier (1964). The cranial/dental
fragments OH 4 and 6, the foot OH 8, and the clavicle
OH 48 (all Bed I), plus the fragmentary skull OH 13
(Bed 11) were designated paratypes. A long argument(summarized by Tattersall, 1995) ensued over the legiti-
macy of this new species; at the time of writing most
authorities (e.g., Wood, 1992) would agree, if only pro-
visionally, that all of the non-Paranthropus hominids
from Olduvai Bed I and lower and middle Bed I1 are
appropriately assigned to Homo habilis. This applies even
to the postcranially spectacularly primitive (Hartwig-
Scherer and Martin, 1991) fragmentary skeleton OH 62
(Johanson et al., 1987). The calvaria OH 9 fi-om toward
the top of Bed I1 is, however, recognized to be clearly
distinctive. Authors such as M. Leakey (1971a) and
Rightmire (1990) place this specimen squarely in Homo
erectus, while others (e.g., Tattersall, 1997, Tattersall and
Schwartz, 2000) doubt this. Whatever the appropriate
name, Rightmire is probably expressing a consensus
when he associates with OH 9 the Bed 111 or IV partial
mandibles OH 22 and 51, the Bed IV OH 12 fragmen-
taq braincase rear and OH 28 innominate/femoral
diaphysis, and the Masek OH 23 mandibular fragment.
How long this consensus will endure is uncertain.
Holloway (2000) provides the following cranial capaci-
ties: OH 7: 687 d, OH 13: 650 ml; OH 24: 590 ml;
OH 9: 1067 ml.MORPHOLOGY
The large number of Olduvai specimens attributed to
the genus Homo represent a morphologically varied
assemblage. Provisionally, they appear to sort out best
as the craniodental morphs suggested below. Since
many of these important specimens have not been
described in comparable fashions we present them in-
dividually and at some length. The unique specimens
are illustrated as well as the most informative ones.OH 13 Morph (includes OH 6,21,30,41,42)
OH 6. Various very thin-boned cranial pieces, part
of petrosal, and isolated teeth. Partial petrosal with
patent subarcuate fossa and no arcuate eminence.
Isolated, just-erupted R12 very shoveled, low crowned,
broadly spatulate. Also unempted crown of LP1 with
low, distinct metaconid (opposite protoconid); large
trigonid basin bounded by long m/l oriented paracristid
that kinks back to join base of metaconid; large talonid
basin bounded by low-set crest. Also part of RM’
or M2: highly cuspulated, large hypocone, peripherally
placed cusps.
OH 13. Highly incomplete calvaria reconstructed
from numerous fragments, including a parietal plus