NARIOKOTOME
(West Turkana)
LOCATION
Exposures (site NK3) some 5 km inland from the
western shore of Lake Turkana, northern Kenya, on
the south bank of the Nariokotome, an ephemeral
stream that enters the lake some 70 km N of Kalakol.
DISCOVERY
First fragment found by Kamoya Kimeu, August
1984; excavation by R. Leakey, A. Walker, and col-
leagues completed September, 1988.MATERIAL
KNM-WT 15000, a remarkably complete skeleton,
including much of the skull, of a presumed male
adolescent.DATING AND STRATIGRAPHIC CONTEXT
Nachukui Fm of the Omo Group. The fluviatilel
lacustrine Nachukui Fm has been divided into eight
Members separated by tuffs (Harris et al., 1988); the
hominid derives from the lowest part of the Natoo
Member, between tuffs that correlate geochemically
with the well-dated KBS (below) and Chari (above)
Tuffs in the Koobi Fora Fm to the east of Lake
Turkana. It also lies below the Lower Narioko-
tome Tuff, which overlies the Chari in west Turkana
and is locally dated by KAr to 1.33 Ma (Brown et al.,
1985), and above the Morutot Tuff, whose geochemi-
cal equivalent east of Lake Turkana has been dated to
1.64 Ma (McDougall et al., 19%). The Chari is datedto 1.39 Ma; extrapolating the sedimentation rate be-
tween the Lower Nariokotome and the Chari Tuffs
downward yields an age of 1.56 Ma for the hominid
site (Brown and McDougall, 1993). This age estimate,
a little younger than the 1.65-1.55 Ma originally pro-
posed by Brown and Feibel(1985) is supported by the
age of the Morutot Tuff and by the securely estab-
lished 1.88 Ma age of the KBS Tuff that lies below
the latter.ARCHAEOLOGICAL CONTEXT
None.PREVIOUS DESCRIPTIONS AND ANALYSES
KNM-WT 15000 was initially described by Brown
et al. (1985) as that of a 12-year-old male Homo
erectus. Dental age was later reduced to perhaps
9-10 years by Smith (1993), but with the remark
that skeletal maturation was advanced by Homo
sapiens standards. The attribution to Homo erectus
was, however, maintained by all of the contributors
to the final descriptive monograph on WT 15000
(Walker and Leakey, 1993), and has been accepted
by many others, including Rightmire (1990). Some
writers, however, regard Homo erectus as a local east-
ern Asian phenomenon, and prefer to attribute
“early African Homo erectus,” including WT 15000,
to Homo ergaster (e.g., Wood, 1992, Tattersall,
1995). Schwartz and Tattersall (2000) have pointed
to the dental and mandibular dissimilarities between
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