[arthurus]

In life, the creature had several tentacles like an octopus or squid which it could use to grasp its prey, but these fleshy parts did not survive the fossilization process.

Okay. So how is it known that there were tentacles?

[SunkenCiv]

I think there have been a handful of specimens in which the tentacles were fossilized. If not, then it’s an assumption. And perhaps sometimes a tautology. :’)