• Subclass: Coleoidea
  • Order: Sepioida

Fossil squids are the only cephalopods whose preserved soft body parts have been discovered with the exception of one fossil octopus specimen found in Lebanon in the late 1800’s. The study of fossil and recent squids and octopui provides some insight into the life and habits of the long extinct but intriguing marine creatures, the ammonites.

The cuttle-bone of a fossil squid is the only evidence of these creature’s existence in the Western Interior’s Late Cretaceous seas. In some areas of the Pierre Shale and Fox Hills Formation, the remains are quite plentiful. These animals have remained virtually unchanged since that time.

The illustration below is of the remains of an extinct Pierre Shale squid known as Tusoteuthis. This ‘cuttle-bone’ shows close similarities to some extant (living) squids.
Although specimens are rare, the evidence is present to show us that rapid-moving shell-less cephalopods existed with ammonites and nautilus.