264 A F R I C^11
the Member 5 StW 80 crushed mandible strongly re-
sembles SK 15 from Swartkrans (the type mandible
of “Telunthropus cupensis”), which they would now
assign to Homo erguster (Clarke, 1994). Robinson
(1962) also mentions other Homo fossils from Sterk-
fontein, but this claim still awaits confirmation.
MORPHOLOGY
The two specimens are described separately below.
stw 53
Cranium in fragments (a-g). StW 53a is damaged
frontal region, 53b is lower face in the following
pieces: 53a is the frontal; 53b is maxilla with teeth
(b/a-i); 53c is part of R zygoma, 53d is part of R tem-
poral, posterior parietal, and lateral part of occipital;
53e is part of L parietal and possibly adjacent portion
of occipital; 53f is lateral part of L occiput; 53g is
damaged L petromastoid; 53h is part of R ramus pre-
serving tip of coronoid; 53i is a possibly associated
isolated LM3. 53d is much lighter in color than the
rest. Not all pieces may represent the same individual.
StW 53a
Frontal damaged and reconstructed, preserving R
superior orbital margin and most of midsection of the
bone. Rather thick boned for such a small skull.
Superior orbital margin unusual in being very thin
and short s/i. Supraorbital notch large and medially
placed, with supraorbital margin thickening s/i lateral
to it. Glabellar region was probably quite broad and an-
teriorly swollen. Seen from above, glabella emphasized
by posterior curve of superior orbital margin in region
of broad supraorbital notch. More laterally, supraorbital
margin becomes more anteriorly projecting, to level
with the glabellar region. Postorbital constriction was
probably quite marked. Superomedial corner of orbit is
“cut off,” truncated by superiorly thickened interorbital
pillar. Immediately lateral to this, supraorbital margin is
indented a/p and thin s/i (although thickens slightly
laterally); medially it is thinned by a wide notch below.
Zygomaticofrontal suture faces quite laterally, not
down. Superior orbital roof distinctly concave, curving
back sharply on to posttoral and postglabellar slopes;
behind is frontal slope rising only modestly. Fron-
tomaxillary suture oriented anterolaterally; suggests
frontal process was turned out somewhat, not facing
forward as in R maxillary fragment (different individ-
ual?). Small portion of R nasal bone preserved in 53a;
in profile, quite outwardly turned and projecting (this is
not consistent with flat nasal bones of lower facial frag-
ment). Postorbital constriction was probably fairly
marked; on the R, a thickened band-like temporal line
arises behind supraorbital margin (creating “corner” of
frontal trigon). Interorbital region would have curved
from side to side on frontal; on maxilla, would have
been flat across. R and L temporal lines curve back
from their origins, parallel to midline, and do not con-
verge. Behind, frontal slightly domed in posterior mid-
line of frontal trigon. Large sinus (probably divided in
midline by septum) pervades region of posttoral/post-
glabellar plane; as seen on the L, it descends down be-
tween bone of orbital cone and that of anterior cranial
fossa, in front of region of frontal lobe (thus sinus may
not be of ethmoid origin). Bilaterally, sinus extends to
temporal lines; posteriorly, to rear of posttoral/post-
glabellar plane. Internally, frontal crest was long and
thick. Frontal lobes were separated anteriorly by a large,
deep fossa. As seen on the L, frontal lobe did not
extend fully over orbital cone. On frontal, above L
temporal line, is a small healed depression, apparently
traumatic.StW 53b
Maxilla and lower face, with most of nasal aperture.
Broken off below nasion, but part of frontomaxillary
suture is preserved on the L, quite low down. Nasal
floor missing.
In profile, preserved portion of nasal bones shal-
lowly concave (suggests glabellar region would have
been anteriorly protrusive). In frontal view, nasal bones
gently widen inferiorly; slightly sunken compared to L
frontal process. Interorbital region was moderately
broad. Inferior margin of orbit preserved; angles down
and laterally. Nasal bones bear slight median keel
which does not extend to their inferior margins. Lat-
eral to superiorly sharp lateral crest of nasal margins, a
low, rounded thickening of bone descends below infe-
rior margin to become confluent with bulge of C root.
Preserved plane of infraorbital region vertically ori-
ented and anteriorly facing. Lateral crest becomes
blunt and rounded inferiorly. As seen on the R, infra-
orbital plane anteriorly facing and vertical s/i, and
slightly concave lateral to this thickening. On the L,
frontal process foramen lies in this shallow depression,
near inferior orbital margin; somewhat posterior and
lateral to this is part of the margin of a relatively large
infraorbital foramen lying quite close to inferior orbital
margin. Infraorbital foramen probably had groove