ammonoid

An extinct cephalopod of the subclass †Ammonoidea (including ammonites).

Although the extinct externally shelled cephalopods ammonoids have an extensive fossil record, their soft tissues are very poorly known and, like extinct and living nautiloids, they are largely presumed to not have possessed an ink sac.

Characteristic of an ammonite.

Literally tens of pence with an ammonoid fossil to highlight how bling bling the world of palaeontology has become