Cuttlebone

The cuttlefish ( Middle Low German cuttlefish (e) = Shell ( shell ) ) is reduced to an internal skeleton shell of certain cephalopods ( Cephalopoda ), namely belonging to the Zehnarmigen squid cuttlefish.

The original cephalopods were shelled organisms ( nautiloids and ammonites ) with a chambered outer shell, as it has Nautilus today. This shell has been incorporated in the course of evolution only in the body ( the cuttlebone Coleoida ) and been reduced more and more in later steps. Thus, the belemnites still had a large chambered internal shell, which could be used as a buoyancy organ and was weighted at the rear end with a rostrum.

This chambered shell exists in the Zehnarmigen squid even today, albeit in reduced form. While the Posthörnchen ( Spirula Spirula ) still has a distinctly chambered cuttlebone, the cuttlebone of cuttlefish ( Sepiida ) has already significantly reduced, a chambering thing is to recognize under the microscope yet. The cuttlefish can still be used by gas storage for the static lift.

The squid have the original shell only one designated as Gladius flat Chitinstab which serves as a skeletal element. The designation is based on the shape of the structure based on the Roman Gladius short sword.

In the eight-armed squid and the vampire squid the shell is completely gone.

The cuttlefish has an economic importance as Schnabelwetzstein for cage birds and Kalklieferant for reptiles (eg, turtles ) in the terrarium and free range. It is also used by masons to remove dried ink of polished stones, and serves as a mold for gold work.

Micro- Computed tomographic 3D representation of a sepia Kalkschulps

Overview of a section at high resolution, about 5 microns / voxel.

Higher magnification.

Detailed representation at very high magnification. Web width of the vertical structures about 10 microns.

Flights by the associated micro - computed tomography image stack

Flight by the corresponding μCT image stack, cutting plane about 30 °, supervision.

Flight through the aligned μCT image stack, side view.

Flight through the aligned μCT image stack, supervision.

Flight through the aligned μCT image stack, supervision, detail enlargement.