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Architeuthis
and Mesonychoteuthis, the giant and
colossal squid, are enigmatic and awe inspiring animals. Very little is
known about the lifestyle of these spectacular animals, despite the
examination of numerous corpses of Architeuthis, much of what we
know about the animals� behaviour and lifestyle boils down to educated
speculation. What is not so well known is that these modern squid were
not the first giant squid in the Earths oceans,
we have tantalising remains of animals that were at least as large as
these modern species that shared the oceans with the ammonites,
mosasaurs, giant turtles and plesiosaurs
about 80 million years ago during the Late Cretaceous period. Imagine
the difficulties of reconstructing these ancient animals when all we
have to go on are fragmentary fossilised remains of the pens, or
gladius, of these animals!
The teuthid
gladius is the internal remnant of the
exterior shell of the primitive nautiloid
ancestral
cephalopods.
The gladius is contained within a �shell
sac� to which the muscles are attached, the gladius
providing strengthening and support for the mantle, the main body of the
squid.� �Fossil Teuthids�
are largely identified and classified by variations in the shape of the
gladius alone and comparisons with living
species of
cephalopods;
soft bodied parts, in those rare cases of exceptional preservation, are
not generally diagnostic or much use in determining species
interrelationships. Unfortunately the gladius
alone does not help us to understand how these animals appeared and
behaved in much detail; one only has to think of the wide variety of
body shapes, visual displays, variations in habitat and behavioural
differences in living
cephalopods
to imagine how much we have lost and will never be able to reconstruct
with these ancient animals.
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