134 A ~i R I c A
represented photographically; for images of these, the
reader should consult Wood (1991). Similar speci-
mens (including those similar to fossils known from
elsewhere) are grouped as potential morphs in the
listing below. Individual specimens from Koobi Fora
that are of note but without evident counterparts are
discussed under the general category of “Others.”
ER 1470 Morph
KNM-ER 807. Partial R maxilla with broken M1
and 2 and complete M3. Teeth huge. Roots of M1
extraordinarily splayed in all directions; comparable to
- Roots of M2 less so, but all roots very long. Very
large protocone fills trigon basin in M1, in which
metacone is not appreciably smaller than paracone.
Hypocone large but compressed mesiodistally and very
square in occlusal outline. Enamel could have been
deeply wrinkled in Ml, as on M2-3. On M2, buccal
side of tooth was probably smaller than on M3.
Hypocone, although large, is compressed mesiodistally.
M3 is dominated by protocone and paracone; detail of
rest of tooth obscured by wrinkling.
KNM-ER 1470. Partial cranium lacking most of
base, nasal cavity structures, posterior part of palate,
and all tooth crowns. Neurocranium reconstructed
from numerous fragments, but good contacts between
fragments indicate reliable reconstruction. Elsewhere
also extensively reconstructed; orientation of lower
face vis-a-vis upper face uncertain, as is that of upper
face relative to neurocranium. As reconstructed, prog-
nathism may be too great. Surface detail in various
regions of neurocranium badly affected by weathering,
notably on parietals and in occipital region, where
hardly any detail remains.
Neurocranial bone relatively thin, especially ante-
riorly; exposed bone posteriorly shows very thin inner
and outer bone tables (thickness mostly produced by
diploe). In profile, frontal rises moderately steeply,
directly from the s/i tall, somewhat swollen glabella
that noticeably overhangs nasion. Well in front of
bregma, profile turns back smoothly in a low, broad
arc that almost levels off until far back along parietals
(probably to behind asterion), then descends in an al-
most perfectly smooth posterior curve right around
occipital and nuchal planes. Slight localized bulge in
area of external occipital protuberance. Maximum
cranial height is at bregma or just behind. Although
profile of occiput is quite smoothly rounded, nuchal
plane is tucked underneath braincase and would have
flowed forward somewhat horizontally. Viewed from
above, tori retreat from glabella, then swing slightly
forward toward their lateral extremities. (As recon-
structed, a gap is left on better preserved L side, be-
tween lateral and central parts of torus. If this gap
were closed, lateral part of torus would be oriented
more anteriorly, with implications for reconstruction
of rest of face.) Also from above, postorbital constric-
tion is marked; neurocranium remains narrow some-
what beyond immediate area of temporal fossa.
Maximum width across parietals thus lies quite pos-
teriorly, more or less directly above maximum width
of cranium, which is achieved across mastoid regions.
From front, face is very broad across zygomas, which
taper up and inward toward narrower braincase.
Lower face is also fairly broad across. From rear,
braincase is slightly taller than wide. Inferiorly, the
relatively straight, slightly inwardly tilted side walls
curve outward along the expanding surfaces of the
mastoid regions. Superiorly, rear profile of side walls
curves broadly and smoothly around to midline of
skull.
Supraorbital tori somewhat damaged, internally
revealing extensive frontal sinuses, especially on the L,
where pneumatization extends about to midpoint of
orbit. Also considerable sinus penetration up into
frontal. Tori almost continuous across glabella, sepa-
rated only by shallow indentation in midline. Tori
rapidly taper laterally; their thickness is significant
only in their medial one-third. Below, tori flow
smoothly into orbital roof. Very little toral projection,
what there is being limited to region around glabella.
Glabella fairly bulbous but shallowly indented in mid-
line. Orbits asymmetrical as reconstructed; it appears
that R orbit is closer to original subcircular configura-
tion. No posttoral sulcus. Plane of upper aspect of tori
continuous with moderately rising frontal. Temporal
lines most visible in region immediately behind tori
and are not detectable posteriorly (probably due to
weathering of bone).
As reconstructed, nasals and associated frontal
processes of maxilla are off-center to the R (if aligned
properly, would bring preserved L lacrimal crest more
into line with preserved inferior portion of L orbit.) L
lacrimal fossa was narrow and shallow. (If nasal bones
were properly aligned, fossae could be shifted back-
ward and rotated slightly to the L, bringing rest of face
with them, and making alignments of frontal processes
of zygomatics more symmetrical and lower face more
orthal.) Nasal bones parallel-sided in their preserved