Table 1 DIK-1-1f comparative anatomy.

ML, mediolaterally; DP, dorsoplantarly; PD, proximodistally.

BoneHuman-like featuresApe-like featuresAdult A. afarensis featuresDevelopmental changes in
A. afarensis morphology
CalcaneusLateral plantar
process apophyseal
flange position
Secondary ossification
center for peroneal
Large depression for
calcaneofibular ligament
Gracile in juvenile; becomes
more robust in adults
Plantarly wide (ML) tuberDP short and vertical
cuboid facet
Small lateral plantar process
apophyseal surface
Rugosity for lateral plantar
ligament not present in DIK;
present in adults
Medial tubercle flat
(not beaked)
Medially angled distal
calcaneus at peroneal
trochlea inflection point
Low DP height of distal
calcaneus; enlarges
in adults
TalusModerately wedgedML broad talar headWeak angle of declinationHead expands DP
Equal heights of trochlear rims
ML flat trochlear body
Talar axis angle
CuboidPD elongated laterallyArticulates with navicularUnknownUnknown
Dorsal surface twisted to
face laterally
Beak eccentrically positioned
Medial cuneiformDistally positioned tibialis
anterior sub-bursal sulcus
ML convex Mt1 surfaceML convexity and angulation
of Mt1 surface greater
than in humans; less than
in apes
Mt1 facet maintains
convexity developmentally
Mt1 facet becomes less
medially oriented
Lateral cuneiformContact facet with Mt4PD foreshortenedTransverse arch more
developed than in apes;
less developed than
in humans (especially
Juvenile is PD short and
becomes more elongated
with age
Intermediate cuneiformNested into angled lateral
surface of medial cuneiform
NavicularFacet for medial cuneiform
slightly convex DP and ML
MetatarsalsStrong external torsion Mt4Mt2 proximal base weakly
angled ML
Mt2 base enlarges DP
Mt4 base DP tall