Koosi FORA (INCLUDES EAST TIJRKANA, ILERET) 141
well-defined crest; another weak crest lies medial to
the latter structure. On the L, anterior to and
roughly in line with the occipitomastoid crest, lies a
small depression (probably styloid pit). Lateral to
this and separated by two small crests, is a foramen
of moderate size that we identify as styloid foramen.
Anterior to both pit and foramen are the remnants
of a ridge along the ectotympanic tube that probably
represents the vaginal process; it fades out well
before reaching lateral margin of the tube.
Superior nuchal line, well defined by a sulcus be-
low it, curves around to midline where it forms a
widow’s peak with the midline bulge above it. Nuchal
plane very rugose, with numerous muscle scars and
well-defined median occipital crest.
R side of foramen magnum is preserved. Foramen
was evidently of moderate size, probably broadly
ovoid. Anterior margin of foramen lay anteriorly, in
line with axis of articular fossa. Preserved occipital
condyle quite elevated; its surface is long and strongly
arced alp. No depression (posterior condylar foramen)
behind it. Basiocciput evidently rose quite steeply in
front of foramen magnum, suggesting a considerable
degree of basicranial flexion.
Palate long, modestly deep, and parabolic, with
short anterior slope and some slope at sides. Incisive
foramen large, extending back to front of P~s, with
long, forwardly inclined sulcus in front almost reach-
ing alveolar crest.
Sutural detail lacking on skull surface; height of
occiput impossible to surmise.
Internally, superior surface of petrosal is flat and
broad; lacks superior petrous sinus and arcuate emi-
nence. Area of subarcuate fossa flat and filled in.
OthersKNM-ER 1482~. Damaged L corpus around sym-
physis to RM1. Quite narrow at front; tooth rows
strongly divergent. Corpus bone thick right to inferior
margin. Preserved P2s very odd; b/l wider lingually than
buccdy, with slightly twinned protoconid. No mesial
fovea; instead, metaconid positioned mesially. Metaconid
huge, extending across midline of tooth. Postcinguhd
very thick; separated from metaconid by deep crease;
swings around back of tooth, enclosing small distal fovea.
Ms, although quite heavily damaged, would have been
b/l wide and somewhat rounded. Hypoconids extended
across midline in all molars. Most (if not all) of M3
would have been obscured by rising ramus.KNM-ER 1805. Braincase reconstructed from many
pieces, lacking most of base, upper face missing; crushed
maxilla and nasal region; also mandibular corpus with
RM2 and 3. Cranial bone variable in thickness.NEUROCRANIUM
Thick boned and robustly built. Relatively straight sided
when viewed from above. Facial skeleton would have
been hafted well forward. Toral region lacking; little al-
isphenoid preserved, so difficult to tell extent of postor-
bital constriction. Slope of frontal difficult to ascertain;
may not have been dramatically different from some ro-
bust specimens. Temporal lines faintly preserved; appear
to converge toward back, where they almost coalesce
(without crest formation) well behind bregma, forming
two stout but rather low parallel crests that decrease in
height just before lambda (lambda visible on internal
braincase surface). At lambda, crests separate, paralleling
lambdoid sutures to region of nuchal crest and forming
distinct triangular surface with the latter. Triangular sur-
face is pronounced and especially ledge-like laterally,
arcing gently across rear of skull between mastoid
processes.
Nuchal crests become more shelf-like as they
course laterally and over mastoid processes. Mastoid
processes (more properly, eminences) are flattened
posteriorly and angle forward almost as steeply as the
nuchal plane. Considerable erosion of surfaces of the
skull rear, but clearly there was considerable rugosity of
the nuchal plane. Mastoid eminence swollen laterally;
inferiorly it extends beyond base of the ectotympanic
tube, which it partially envelops. Medial to mastoid re-
gion is a deep, moderately broad notch with a long,
thick, ridge-like elevation of bone on its medial side. It
is tempting to regard the gutter as a mastoid notch (but
with no digastric fossa behind it) and the ridge next to
it as an occipito-mastoid or paramastoid crest. How-
ever, in absence of any sutural indications, it is unwise
to attempt to suggest homologies. Furthermore, there is
a groove on the medial surface of the crest, behind
which there is a shallow depression. Thus it is impossi-
ble to determine with any certainty on which side of
the crest the digastric tendon ran.
Ectotympanic tube oriented obliquely backward;
extends quite far laterally. On the L, it appears that
the auditory meatus was probably quite large and cir-
cular. Low vaginal process runs along midline of ecto-
tympanic tube, extends quite far laterally before fading
out, and would have peaked quite medially. A fairly
large pit (probably stylomastoid foramen) lies in line