When you see a fantastical creature you don’t recognize from the usual European pantheon, odds are it’s a safari animal whose description the artist read in Roman sources, or heard about from a patron who had read the Roman sources, or possibly picked up from crusaders telling tall tales at the Green Dragon Inn after a few pints. This is how you get lions with barbed tails, giraffes with loop-de-loop necks, and so forth.
But would someone please explain to me what this thing is? Is it a baboon? A dog? A pachycephalosaur?