Compare the lateral views of the skulls below. In the middle is P. aethiopicus
represented by WT 17000 (the "Black Skull"). To the left is a composite
reconstruction of a male A. afarensis, and to the right is ER 406 -- P.
boisei (ER 406 image is reversed for easier comparison).
Note that:
- the degree of prognathism in the lower face of WT 17000 is more similar to A. afarensis than it is to P. boisei,
Draw an imaginary line vertically from the orbits (eye sockets)
and note that the projection of the faces of A. afarensis and P.
aethiopicus is greater than P. boisei. The face of P. boisei
is higher (from the top to bottom) relative to its forward projection.
- the shape of the back of the skull of P. aethiopicus (produced by
the sagittal crest's being positioned well to the rear of the head) relative
to P. boisei (with the sagittal crest resting near the top of the head)
also is more similar to the earlier A. afarensis species.
Look at the nuchal plane of the skulls. This is the plane formed
by where the neck muscles join the back of the skull, and can be seen in
each of the skulls as a flat section to the lower right, angling up to the
right. Follow the nuchal plane up to its end, where the top of the skull
meets the plane. Compare the shape of the three skulls. At this point you
will notice that, again, P. aethiopicus is more similar to A.
afarensis.
Back to P. aethiopicus page
|
