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could be answered only by looking in more detail both at the fossils and at
modern nautiloids.
In late 1994, Saunders and I finally got around to looking at the soft-
part anatomy of
Nautilus scrobiculatus.
We performed a series of parallel dis-
sections on the soft parts of the King Nautilus and
Nautilus pompilius.
The time-honored method of comparative anatomy is one of the most
powerful methods applied in elucidating evolutionary relationships and thus
is a "time machine" in its own tight. Our work showed that
Nautilus scrobic-
ulatus,
the so-called King Nautilus, was distinct in many anatomical charac-
ters, such as gill and reproductive system morphology, shell ultrastructure,
and morphology of the hood. Thus in soft-part as well as hard-part anatom-
ical featutes, it was clearly distinct. But was it ancestral, or was it a descen-
dant of some
Nautilus
species, or was it completely unrelated? To addtess
such evolutionary issues, we needed to perform a cladistic analysis, and to do
that,
we needed to know which characters were primitive and which derived.
Unfortunately, we still did not have enough information to make such judg-
ments. Hence we turned to a new source of evolutionary evidence: the genes
of the nautiloids themselves.
By the 1980s, extremely powerful techniques based on DNA sequenc-
ing afforded investigators new ways of testing phylogenetic hypotheses such
as those we had framed for the living nautiloids. The power of the DNA
methodology is that, unlike the traditional nautiloid taxonomy pioneered by
Miller and Kummel, it looks at many individual characters (the genetic
arrangements) rather than only a few (the shell and sutute characters) and
thus allows the use of the new cladistic approach. But for these tests, tissues
from live animals had to be obtained, frozen immediately at very low tem-
peratures, and kept frozen until the laboratory analyses were obtained. This
posed huge problems for those of us collecting samples from living nau-
tiloids. These animals lived in remote, tropical localities. In many such
places there was no possibility of obtaining dry ice, the substance used to
fteeze and then maintain the tissues. The logistics of freezing the samples
and then getting them back to North America from distant tropical regions
was daunting. It took us 5 yeats.
