Here's the other option.
Fashionable Feline: Have you come to help, then? To hunt the meownster Rathalos?
Warrior of Light: After seeing the bounty I couldn't resist!
Fashionable Feline:Thank you, miss, thank you! I knew I was right to post that bill.
So the Palico was the one who posted the bill with Clan Centurio.

Given that we know all the FFXII races are in Dalmasca somewhere, it's not that hard to buy that Palicos exist somewhere either. As for Rathalos, he's probably just a specialized wyrven. We've got plenty of those around already and the Au Ra think there's a dragon living in the Tail Mountains anyway.