What Type Of Animal / Era?

[Taurus Rex]

Hi, we were not particularly hunting fossils but made this find in the sand pumped out by the local authority, to keep a 25 meter deep channel open for Cape size vessels to enter the Richards Bay port harbor in South Africa. We found quite a few of these examples , some a bit larger that the two samples shown in the pictures. The fossils shown here resembles some kind of unusual vertebrae which is tightly layered. The one sample shown has got three distinctive layers, but it could also be aged related? I looked at quite a few pictures on the internet but none resemble the samples shown here. Could you assist with the type of animal and period ?

[RCFossils]

You have a few interesting sections of ammonites

[Auspex]

You have a few interesting sections of ammonites

I agree.

An ammonite was a (usually coiled) cephalopod similar to today's Nautilus. Their shells were a series of chambers (added as the animal grew) separated by walls (the topography of which varied in complexity by species). Your samples are individual chambers that filled with sediment that eventually turned to stone; when the shell material dissolved, these internal casts became all that was left.

[Mattalic]

Cool find - was a pretty big animal at one point

[Al Dente]

I think it is from a coiled nautiloid, possibly Hercoglossa.

[jpc]

Yup... Pieces of nautiloid.

[Taurus Rex]

Al Dente, you have hit the nail on the head!!! Here is some photos of more samples. One sample of a "baby" hercoglossa shows the internal structure of these animals. There seems to be a tube running through from head to tail connecting each of the segments.

[Taurus Rex]

Some photos of segment castings agains the baby sized hercoglossa photo In an earlier post, showing its relative size.

[Taurus Rex]

Some photos of segment castings agains the baby sized hercoglossa photo In an earlier post, showing its relative size.

[Auspex]

The tube connecting the chambers is called the siphuncle; it is how the nautiloids controlled their buoyancy.