Sulcal Skirmishes - The Fossil Chronicles - page 59

was farther forward on the endocast ( L? in figure 7) as indicating the
likely position of the uppermost end of an apelike lunate sulcus, in keep-
ing with the rest of Taung's apelike sulcal pattern as well as with its
small cranial capacity. In my view, the various parts of our ancestors'
brains evolved in a more coordinated manner (i.e., globally) rather than
in a rear-end-first fashion.
In the early 1990s, my dear colleague Charles (Scooter) Hildebolt, of
Mallinckrodt Institute of Radiology, in St. Louis, advised me to redirect
my research from the debate about the lunate sulcus and toward more
positive and potentially productive topics. His reasoning was, “Nobody
reads these lunate sulcus papers anymore. . . . People are getting sick
of them . . . and haven't you said everything you have to say about the
matter, anyway?” 13 Scooter was right, and I decided to take his advice.
During most of the 1990s, my collaborators and I cheerfully researched
the evolution of cranial blood flow, differences between the right and
left sides of monkey and human sulcal patterns, comparisons of the
brains of male and female monkeys and humans, and an assortment of
hominin skulls that lived more recently than australopithecines.
In 1998, an article by Glenn Conroy, of Washington University School
of Medicine, and his colleagues appeared in Science, pulling me back
into the australopithecine fray. 14 The article was about an adult austral-
opithecine skull (with the museum number Stw 505) from Sterkfontein,
South Africa, which was thought to be from an adult male of the same
species as Taung (Australopithecus africanus), a species commonly known
as gracile australopithecines. Researchers had been aware of Stw 505
for some time. Because it appeared to have a huge braincase compared
with those of other australopithecines, the general expectation was that
its cranial capacity, when finally determined, would exceed 600 cm 3 —
which would have been relatively whopping.
I shared that expectation, because my copy of its endocast looked big-
ger than the other australopithecine endocasts in my collection. Using
three-dimensional computed tomography (3D-CT) technology, Con-
roy's team determined that the capacity was actually 515 cm 3 . Although