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Re: Ammonite colouration (was Re: SVP Preview)

> A single pair of gills is what
> separates squid, octopuses, etc. (coleoids) from nautiloids.

Wait a minute. To have 2 gills is normal for molluscs as a whole. To have 4
(and some other doubled organs) is an autapomorphy of *Nautilus* and who
knows how many of its extinct relatives. Therefore a single pair should be
expected a priori for ammonites.

Does the rest of the description really not refer to belemnites (of which
impressions have been known for decades)?