KOOBI FORA (INCLUDES EAST TURKANA, ILEKET) 133
together span the period from about 2.7 to 1.4 Ma,
have produced virtually all of the Koobi Fora hominid
cranial and mandibular specimens. Indeed, hominid
fossils are almost absent from the lower parts of the
Burgi, so that almost all of those known date from
about 1.9 to 1.4 Ma. Among the better-preserved
cranial specimens currently attributed to Homo,
KNM-ER 1470,1813 and 3732 date from 1.90-1.88
Ma; ER 1805 from 1.85 Ma; ER 3733 from 1.78 Ma;
ER 730 from 1.70-1.65 Ma; and ER 3883 from
1.65-1.50 Ma. Among the more complete such
mandibular specimens, ER 1482, 1501, 1802, and
3734 date to 1.90-1.88 Ma; ER 820 to 1.65-1.55 Ma;
and ER 992-1.49 Ma.
ARCHAEOLOGICAL CONTEXT
Stone tools are known from a variety of sites at Koobi
Fora. From the famous KBS tuff itself (1.88 Ma)
come tools of the “KBS industry,” which is essentially
an expression of the Oldowan, consisting of chipped
cores and flakes (Isaac et al., 1971). Slightly later, in
the lower part of the Okote Member (ca. 1.6 Ma), are
found lithics of the Karari industry, which adds large
core scrapers to the earlier toolkit (Bunn et al., 1980).
Indeed, there is an apparent trend over time at Koobi
Fora for toolkits to include larger cores and more
numerous retouched forms (Bunn et al., 1980). At the
very end of the sequence there is one early Acheulean
site (Schick and Toth, 1994). Koobi Fora has fur-
nished a number places on the ancient landscape at
which hominid activity evidently was concentrated;
beyond direct cut-mark evidence of butchering, ele-
ment frequencies indicate that some ancient hominids
obtained parts of relatively fresh carcasses and trans-
ported them to such places for processing and con-
sumption (Bunn, 1986).mens (and less complete specimens from Koobi Fora
resembling them) within Homo erectus (e.g., Right-
mire, 1990); but rumblings were soon heard that
perhaps these fossils were in fact distinct from Homo
erectus and might better be accommodated in the con-
veniently available species Homo ergaster. This position
has, indeed, been accepted by the official mono-
grapher of the Koobi Fora material (Wood, 1992),
although not formally in the monograph itself
(Wood, 1991). Going beyond this, Schwartz and
Tattersall (2000) have pointed to the substantial
morphological heterogeneity present in the ER 3733/
ER 3883/ER 992/ WT 15000 assemblage.
The discovery of the ER 1470 cranium in 1972
was announced as that of a probable member of Homo
(Leakey, 1973), but assignment to Homo babilis of this
non-Homo erectus-like but relatively large-brained
form was felt to be contraindicated at the time by an
erroneous belief that it dated from 2.9 Ma. Nonethe-
less, it was this distinctive specimen more than any-
thing else that ultimately hastened general acceptance
of Homo habilis-ironically, in view of the fact that
many have since concluded that it belongs to another
species, Homo (or even Kenyanthropus) rudo@nsis (e.g.,
Groves, 1989; Wood, 1992, M. Leakey et al., 2001).
R. Leakey (1974) inclined toward placing the ER
1813 cranium in Australopitbecus, and was followed by
several other authors (e.g., Falk, 1986). However, fol-
lowing its 1978 attribution to (a female) Homo babilis
by Howell (who also included ER 1470 in this
species), general opinion has shifted in this direction
(e.g., White et al., 1981). Several other proposed solu-
tions to the problem of how to situate ER 1813 have
been reviewed by Wood (1991); the multiplicity of
such schemes indicates not only the motley nature of
the fossils that have at one time or another been at-
tributed to Homo Aabilis, but also, as Stringer (1986)
eloquently pointed out, the heterogeneous nature of
the Koobi Fora fossils allocated to Homo.
Hollway (2000) reports the following cranial
capacities: ER 1805: 582 ml; ER 1813: 510 ml;PREVIOUS DESCRIPTIONS AND ANALYSES
Among the first specimens of Homo to be found at
Koobi Fora was the mandible ER 992, found in 1971.
This was announced simply as Homo Sp. (R. Leakey, ER 1470: 752 ml; ER 3732: 600-650 ml; ER 1590:
1972), but was not long afterward made the holoVPe more than 800 ml; ER 3733: 848 ml; ER 3883: 804 ml.
of the new species Homo ergaster by Groves and
Mazak (1975). 1975 also saw the discovery of the cra-
nium ER 3733, which was promptly assigned to Homo
erectus by Leakey and Walker (1976), and was joined
in that species shortly thereafter by the calvaria ER
3883 (Walker and Leakey, 1978). Many students were
(and some still are) content to accept all three speci-MORPHOLOGY
Many of the specimens referred by Wood (1991) to
Homo are not included here because too little of the
morphology required by our protocol was preserved.
In some cases, specimens described here are not