Orthocone Nautiloid (Orthoceras)

Orthoceras is a genus of extinct nautiloid cephalopod from Middle Ordovician-aged marine limestones of the Baltic States and Sweden. The name means 'straight horn', referring to the characteristic long, straight, conical shell. The preserved shell is all that remains of this ancestor of our modern-day squid.

The soft-bodied creature lived in the last open section of its conical shell. As it grew, and the space in that part of the shell became too small, a wall called a "septa" formed to separate the old living area from the new one. These different parts of the shell had distinct compositions, which is why we can see differences in how they fossilized.

Now, let's talk about the "siphuncle." It's like a tube that runs from one end of the shell to the other, passing through each of the chambers inside. This tube served two important purposes. First, when filled with water, the nautiloid could push the water out forcefully, which allowed it to move backward using a sort of jet propulsion. Second, by expelling the water and creating an air space, the tube helped the creature control its buoyancy, so it could go up or down in the water to different depths.

Reconstruction by Nobu Tamura

Approximately 68cm long including tentacles. 

This is not a toy. Not suitable for children under the age of 36 months.