Name Any animal that Pokemon never did.

[Tellis]

we need an opabinia pokemon.

Doesn't Anorith fit that bill?

I thought most fossil Pokemon have been pretty varied, actually. We've got an ammonite, a trilobite/horseshoe crab, a pterodactyl, a sea lily, whatever Anorith is (Bulbapedia says Anomalocaris), a pachycephalosaur, a ceratops, a turtle and an archeopteryx. I don't know where else you go with prehistoric animals...