Tentaculites rareannulatus

The Tentaculites constitute a class of exclusively Paleozoic marine organisms. Their taxonomic situation is difficult, they have been included within mollusks due to their similarities with the opisthobranch gastropods that currently live. When studying the fossil remains, a structure similar to cephalopod mollusks is observed inside (they have a siphon and tentacles); However, the structure of the shell is similar to brachiopods.

We have included them in this section because they have conical shells.