Belemnites are extinct squid-like cephalopod mollusks that lived throughout the Mesozoic era. In the Walking with Dinosaurs factfiles, they are said to have been prey for Ophthalmosaurus. They were close cousins to ammonites, featured in the Cruel Sea episode of WWD, but unlike the ammonites, the belemnites had straight shells instead, making them look more modern squid-like than the ammonites. They lacked the squid's special arms, though, just as the ammonites and Cameroceras did.
- These are the one of the first Cephalopods to appear in the series along with the Ammonites.
- Technically, Belemenites were just a single genus in the Belemnitida order of the cephalopods.