Sick Hobbits, Quarrelsome Scientists - The Fossil Chronicles - page 141

were determined to be 1,300 cm 3 and 1,100 cm 3 , respectively . 34 These
capacities were way too high, considering that Hobbit's cranial capacity
was only 417 cm 3 and that an adult size of 400- 500 cm 3 (or grams) was
frequently quoted in the clinical literature for primary microcephalics.
For these reasons, we decided to identify a range of cranial capacities
for the microcephalics in our study by estimating that range from 25
adult microcephalics rather than relying on statistics generated from
normal humans . 35 This procedure led us to conclude that, ideally, we
should include individuals whose capacities were 650 cm 3 or lower in
our microcephalic sample.
As is the case for fossils of our early relatives, microcephalic skulls
are rare. Nevertheless, colleagues in the United States and elsewhere
helped us scrape together skulls and CT data that brought our sample
of them (which included the Basuto specimen) to ten. 36 Despite its small
size, this group was extremely diverse, which increased its chances of
capturing general features that might characterize microcephaly. The
sample included individuals of both sexes ranging in age from ten years
to adulthood and having cranial capacities from 276 to 671 cm 3 . 37 The
microcephalics came from different parts of the world, including the
United States, South America, Europe, and Africa. Most of the speci-
mens were probably primary microcephalics, although at least one was
a secondary microcephalic. We produced virtual endocasts for the ten
microcephalics. For comparative purposes, ten virtual endocasts were
obtained from skulls of normal men and women of African-American
and European-derived heritages. 38 All of these are shown in figure 22.
We thought it was important to explore whether anything other than
absolute size distinguishes the microcephalic brains from the normal
ones. As our critics had noted, microcephaly is an extremely complex
condition. Perhaps the syndrome is so complicated and varied that our
specimens would have nothing in common except their very small brain
sizes. This turned out not to be the case, however. As shown in figure 23,
certain shape features do, in fact, set the microcephalic endocasts apart
from those of normal people. For one thing, the microcephalic endo-