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"cost" the animals in that they had to expend more metabolic energy. An
alternative was to make thin septa but septa so complex that they were
stronger, than thick septa of lesser complexity.
I was privileged to be a grad student of Gerd's at the time he was mak-
ing these seminal discoveries. His office was always open, and we often
talked of ammonites and many other things. Why would they have produced
such complex septa? Could some other function have been involved? Might
the very complexity somehow have been used for a secondary function, such
as some type of respiration, or muscle attachment, or even the removal of
liquid from newly forming chambers? Westermann would mull these possi-
bilities over and then reject them. Structural support seemed the only possi-
bility.
The intricacies of ammonite septa continued to intrigue paleontologists
during the 1970s and 1980s, but Gerd Westermann was king. Refinements to
the model of septa as structural support were made, and Westermann, in col-
laboration with a brilliant post-doctoral student named Roger Hewitt, began
using ever more sophisticated engineering techniques to study these forms.
One generalization reigned: Ammonites with more complex septa were capa-
ble of living at greater depths in greater pressures. It was a story of imperialist
evolution: ammonites invading ever deeper waters through time, colonizing
regions of the sea that were previously too deep for their shells. One could en-
vision legions of new ammonite food succumbing to the first prey—their shells,
and depth, no longer protecting them from these efficient Mesozoic predators.
From Buckland to Westermann was over a century, a long time in sci-
ence. Ammonites were touted as engineering marvels, miniature submarines
with shells designed to withstand the ocean depths. Evolution, that supreme
engineer, even kept improving the design by creating ever more complex
septa. Who could disagree?
The first crack in the edifice of this wonderful paleontological story
came in 1994, and it came from Bruce Saunders of Bryn Mawr College.
Saunders is a specialist in Paleozoic ammonites, which lived from their in-
ception in the Devonian Period, some 400 million years ago, until the end
