Ok, I'll clear this up for you.
They have never been released on the PSP, only ported through illegal actions, hell, I'm not even sure how they did it, but it's to do with AE and AE being available on the PS1.
Now, because this is unnofficial, and in no way supported by OWI, therefore there would be no new content, becuase OWI would have to create it, and because they probably weren't aware that it was being ported to the PSP, they would have been unable, let alone unwilling to add new content, like the paramite stockyards.
Also, if you counted the fireflies, bats, buzzards and even glockuns (in game), there would be 6 new creates, but it's besides the point. The paramites and scrabs were the two major wildlife enemies in the game, spoiling both of them early, would have been useless, the scrabs teased you on what was yet to come anyway.
I hope that helps.
