Travel Reference
In-Depth Information
Until recently, the only assertion that Nautilus might be more ancient
than Millet and Kummel believed came from a Russian named V. Shiman-
sky, who in 1957 published the description of a nautiloid fossil from rocks 30
to 40 million years old in Kazakhstan. He named this specimen Nautilus
praepompilius n.sp. Because it was remarkably similar in shell morphology to
Nautilus pompilius, Shimansky suggested that the genus Nautilus might be
traced back to the mid-Tertiary, rather than to the later Tertiary or Pleis-
tocene. But Shimansky's new species was known only from a single speci-
men, so it was largely ignored by subsequent workers.
Miller and Kummel's claim that Nautilus was very recently evolved,
and therefore had no fossil record, was endorsed by each new generation of
paleontologists interested in cephalopods, including J. Wiedmann in the
1960s, J. Dzik in the 1970s, and C. Teichert and T. Matsumoto in the 1980s.
The latter two had a century of combined experience studying nautiloids by
the time, in 1987, when they wrote an atticle on nautiloid systematics and
evolution teaffirming that Nautilus, though perhaps somewhat older than
Miller and Kummel imagined, was the last-evolved externally shelled cephalo-
pod, was recently evolved, and was the only such creature left in the world
today. Who could argue with this Who's Who among the greatest paleontol-
ogists of the twentieth century?
A new scheme of classification
All taxonomists of this period (including, of course, those working on
cephalopods) used a similar scheme of classification: Organisms were grouped
together into taxa because they shared specific morphologies. Opinions on
which characters were most important in this endeavot, however, were based
on each worker's experience and observations, so they differed greatly among
scientists. "Good" systematic biologists were those who had a "feel" for defin-
ing important characters. This method, called phenetics, was originated and
used by such pioneering eighteenth- and nineteenth-century taxonomists as
Linnaeus, Cuviet, and Owen, and it persisted through the first half of the
twentieth century. By the 1970s, however, a contrasting philosophy and
Search WWH ::




Custom Search