Sulcal Skirmishes - The Fossil Chronicles - page 63

As luck would have it, I got more than I bargained for at Wits. The
last thing I was thinking about when I stepped into the archives was
the debate about the lunate sulcus. After all, Dart had published only
two sulcal identifications for Taung's endocast (the superior temporal
and the lunate, shown in figure 5)—and one of them was simply wrong.
The feature that Dart identified as the lunate sulcus was the lambdoid
suture, pure and simple. After decades of fencing with Holloway about
the matter, I was simply wrung out and had no expectations of learning
anything that would rekindle my interest in the matter.
I was mistaken, however, because Dart's reactions to the controver-
sial storm that greeted his discovery involved extensive soul searching
about Taung's endocast, including his identification of its lunate sulcus.
Dart's voluminous 1929 manuscript that was rejected for publication, for
example, went far beyond his 1925 Nature paper in its analysis of Taung's
endocast . 18 In addition to the two sulci that Dart had identified in his
initial publication, figure 19 of his unpublished manuscript (figure 8 here)
illustrated and named 14 other sulci. And to think, this illustration had
languished unknown in the archives for 80 years!
And a very telling illustration Dart's figure 19 is. For one thing, Dart
used dashed lines to indicate sutures from the skull that were repro-
duced on the endocast. (Recall from chapter 2 that a suture is a ridge
where bones of the skull have knitted together, whereas a sulcus is a
groove that separates swellings of gray matter.) The short dashed line
directly behind the feature that Dart identified as the lunate sulcus (L)
is especially revealing, because he meant it to indicate the lambdoid
suture, which he had not mentioned or illustrated in his initial publi-
cation. On page 168 of his 1929 manuscript, however, Dart stated, “On
the right side of the cast, it [the lunate sulcus] coincides in position
with the lambdoid suture in portion of its extent.” In other unpublished
notes, he wrote, “Lunatus sulcus is present as an arc-like depression
about 25 mm. in length. . . . The lunate depression is almost coincident
throughout a large portion of its course with the lambdoidal suture.”
Dart's belated depiction of a lambdoid suture on Taung's endocast was