Fossil
species composed of six
specimens (a
cranium,
mandibular fragment, and four teeth); recovered from
Toros-Menalla locality TM 266,
Djurab Desert, northern Chad, in 2001. It has a combination of
primitive and
derived traits and, consequently, is proposed as a possible stem for the
hominid lineage. The
holotype is
TM 266-01-060-1, a nearly complete, presumed
male cranium that was recovered in a dorsoventrally flattened condition.
Hominid traits include small
canines, no evidence of a sectorial pre-molar or a
diastema, and cheek
teeth with an
enamel thickness that is intermediate between those of later
hominids and
chimpanzees.
Hominoid features are an elongated and small
brain case (estimated volume 320-380 cm
3) and
apelike features of the
basicranial skeleton and
petrous portion of the
temporal bone. Other traits include a massive single supra-orbital
torus, small
sagittal crest, large ovoid
foramen magnum bordered by small
occipital condyles, and a large pneumatized
mastoid process. There is insufficient
data to ascertain whether this
species was a habitual
biped. The small
canine and large
brow ridge (suggesting this is a male) implies there was very little
sexual dimorphism in
canine size. This
fossil species suggests that the time
period when the chimp-human
divergence occurred should be reevaluated.