for belemnites, cephalopods had
external shells with hollow internal chambers separated by walls called septa. A tube called the siphuncle, connected the body with the
chambers allowing the animal to fill them with water or air, changing
its buoyancy in order to rise or drop in the ocean.
the last and largest chamber was occupied by the living animal.
Belemnites were different in that they had internal shells called
'guards' which were covered with the soft, muscular tissues of their
bodies. These shells were also chambered but much less complex
than the straight varieties of nautiloids and ammonoids.
cephalopods probably lived for one to six years, with the majority living two to
four years. They fed on plankton (tiny free-floating organisms), sea
lilies, and smaller
orthoceras. Although many fed off the ocean floor, others may have
caught plankton while floating or swimming via jet propulsion,
expelling water through a funnel-like opening to propel themselves in
the opposite direction.
Because straight cephalopods lived
exclusively in marine environments, their presence also indicates the
location of prehistoric seas.
famous and very large fossil deposit of these animals known by the
can be found in Morocco, North Africa. Hundreds of millions of years ago, as they died,
their shells accumulated in great numbers on the sea floor where they
were aligned by currents, buried by sediments, and transformed over the
ages into stone. Today, this prehistoric sea floor is ironically,
found in the dramatic Atlas Mountain Range in southern Morocco at the
northern fringe of the Sahara Desert.
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