Belemnite

Taxonomy

Phylum: Mollusca

Class: Cephalopoda

Subclass: Coleoidea

Cohort: Belemnoidea

Diagnostic Features

Diagram with labelled features of belemnites

'Bullet' shape

Phragmocone: chambers divided by aragonitic septa (often preserved as conical cavity)

Radial calcite crystals form the guard

Way of life

Nektonic

Predatory

Marine

Advanced notes

Exceptional preservation of belemnites showing soft parts has shown them to be very similar to squid in shape. The guard and phragmocone were held inside the soft parts of the animals, acting as a kind of backbone.

Because the phragmocone is made of aragonite it is often not preserved. In contrast the calcitic guard is very often preserved. This means that a common preservation of belemnites is of the guard with a conical hole where the phragmocone once was. This empty conical chamber is often crushed.

Specimens

Browse belemnites

External Links

Mollusc World