Biology Reference
In-Depth Information
lost with each successive casting. An endocast from a cast of the cranium
was, thus, likely to be less informative than one made from the actual
braincase. Unfortunately, LB1's braincase (which had been described as
having the texture of wet blotting paper when it was discovered) was
too fragile to cast directly.
Despite my eagerness to see what, if anything, would be revealed by
an endocast from a replica of LB1's skull, I suggested that we also obtain
a “virtual endocast” from the data that had been collected from LB1 in a
medical computed tomography (CT) scanner in Jakarta Selatan, Indo-
nesia (before the specimen was removed to Jacob's laboratory, where
it was damaged). I knew that the scanner's X-ray source and array of
detectors had collected slices of data that had been compiled to recon-
struct LB1's skull in three dimensions and to visualize it on a computer
screen. Once we had a copy of LB1's virtual skull, we would be able to
flood-fill its braincase electronically to create a virtual endocast.
Although they haven't been around that long, virtual endocasts are
clearly the way to go when studying brain evolution from prehistoric
skulls. For one thing, these endocasts are created without ever touching
the actual skull (except to place it on the scanner), whereas preparing
latex endocasts is an invasive procedure that risks damaging specimens.
Virtual endocasts also reproduce exquisite details of the cerebral cor-
tex compared with the details collected through latex endocasts made
directly from skulls, let alone second-generation endocasts made from
can be rotated, partitioned, and measured electronically, which gives
more precise information than one can collect by measuring solid endo-
casts with old-fashioned hand-held calipers. With a virtual endocast,
missing parts are also easier to reconstruct, by electronically transfer-
ring a mirror-image of a part that is present on one side to the other,
which is extremely challenging to do by hand. One advantage of solid
endocasts, however, is that they are easier to view in one fell swoop—
no electricity needed. Fortunately, hard copies can be made of virtual
