180 AFRICA
WT 15000 and the type specimen of Homo ergaster,
KNM-ER 992, as well as between both of these and
the classic Homo erectus specimens from Java.
Holloway (2000) quotes a cranial capacity of 900 ml.
MORPHOLOGY
We describe an adolescent cranium missing central
and internal parts of upper face, parts of skull vault,
and anterior part of basicranium (all upper teeth
present except for unerupted RM3). Also complete
mandible of same individual; M3s not visible. Lacu-
nae in braincase indicate that bone is of considerable
thickness for a subadult individual.
Cranium
Long, low. In profile, frontal rises gently in smooth
curve from what was apparently a shallow sulcal plane
that widened laterally behind mostly missing supraor-
bital tori; maximum cranial height achieved around
bregma, behind which there appears to be a shallow
depression in a profile which then continues smoothly
around and down to the superior nuchal line, just
above which is a nother broad, shallow depression.
Below this, the nuchal plane curves smoothly down-
ward and forward. Seen from above, maximum width
is achieved above mastoid processes, with a strong
angle forward to the pronounced postorbital constric-
tion, and a smooth curve around the neurocra-
nium behind. On the L, preserved lateral part of
supraorbital margin curves strongly backward. From
behind, braincase is somewhat tent shaped, but with a
reasonably smooth profile curve.
Face appears deep, narrow. Supraorbital region
largely missing, but there is clear evidence of frontal
sinuses, well preserved on the L, that penetrate quite
far into frontal and laterally at least to midline of
orbits. Laterally over L orbit, supraorbital torus is
moderately tall s/i, but lacked upward projection;
there was probably significant forward projection on
each side. Roof of orbit made a distinct angle with
torus. Tori probably did not taper laterally; they re-
main substantial right across to zygomaticofrontal su-
ture. Viewed from above, preserved lateral portions of
tori retreat at their lateral extremities quite markedly
from the presumed position of glabella.
Orbits taller s/i than wide m/l, truncated in in-
feromedial portion (because lateral margins especially
deep). Superior extremities of both nasal bones pre-sent, apparently with frontonasal sutures. Nasal bones
would have been long, only slightly tapering, with
modest flexure below the rather low nasion. Frontal
process of maxilla penetrated by maxillary sinus to re-
gion just medial to infraorbital foramen; sinus fails to
swell out process, which instead curves out anteriorly
to contact nasal bones. Medial wall of capacious max-
illary sinus appears to encroach very slightly on nasal
cavity as it proceeds posteriorly. In nasal cavity, wall of
maxillary sinus intrudes somewhat posteriorly, but re-
mains concave in vertical plane. Superiorly, there was
some anterior projection of lateral nasal margin. Sub-
glabellar prognathism was thus achieved less by pro-
jection of nasal bones themselves, than by forward
curvature of lateral nasal margins.
Nasal aperture was large, notably wide superiorly,
but not tall s/i. Anterior part of lateral nasal wall is
completely preserved on the R, just within the aper-
ture lies a short, low, more or less horizontal concha1
crest. Behind the crest, a vertical shelf of bone extends
partway over lacrimal canal. Lateral nasal crests (mar-
gins) are relatively sharp; descend to fade out below
level of rounded, indistinct, inferior nasal margin. Na-
soalveolar clivus long, strongly forwardly inclined;
flows smoothly into relatively flat nasal cavity floor
which declines very slightly posterior to posterior pole
of nasoalveolar clivus. In midline of floor there was at
least a modest eminence in region of anterior nasal
spines; very low spinal crests run laterally from the
posterior part of this eminence. Nasoalveolar clivus
slightly convex, with some undulations reflecting
tooth roots beneath. Facial pillars absent; there is a
shallow concave surface below the infraorbital fora-
men. Anterior root of zygomatic arch originates a
moderate distance above alveolar margin. Zygomas
vertical, not flaring. Zygomatic part of maxilla faces
anteriorly, whereas a sharp angulation just posterior to
zygomaticomaxillary suture causes body of zygoma to
face directly laterally. Malar tuberosity thus faces
backward. Inferior margin of zygomatic arch slopes
consistently upward, while turning at zygomaticomax-
illary suture from lateral to posterior orientation. Both
zygomatic arches missing; enough remains to indicate
that arch sloped slightly up and back.
Faint temporal lines (best seen on L, where inferior
and superior lines discernible) run behind lateral part
of tori and course straight back, fading out around
coronal suture. Temporal bone was rather long, but did
not rise very high s/i. No demarcation of infratempo-
ral from temporal fossa. Anterior squamosal suture