Thanks for the scan. Oh what a great chapter, if only for the return of him.
Here’s the Wikipedia page for the manticore, for those who aren’t familiar with the creature. Manticore are supposed to have three sets of teeth and a scorpion’s tail, which the manticores in Impel Down lack, though it might not be a coincidence that the manticore are shown together with the puzzle scorpions. I'd assume the puzzle scorpions themselves are an original creation of Oda’s.
edit: Maybe I should explain about the puzzle scorpions, since they confused me at first. They are apparently scorpions that latch together to form into a giant centipede-type thing. The claws of each scorpion becomes the legs for each section of the "centipede". They then apparently come apart again to attack prey. I say apparently because none of this gets explained in the chapter, all that's said about them is Buggy shouting that the big centipede exploded, and Mr.3 says that they're supposed to be more than one like that (that is, that the "centipede" was never a single entity), that they're puzzle scorpions, and that they're poisonous. Luffy is blocking most of the scorpions still linked into the "centipede", making it just looks like there's some scorpions floating around, so you really have to look hard at the picture to figure out what Buggy was talking about. Or at least I did.
Eveyone's probably already familiar with the sphinx. The one in Impel Down has wings like the Greek one, but lacks its intelligence.
@Monkey:
So perhaps Ace,Jimbei and Cror are in lvl 6? Cuz i thougt it was only lvl 1 to 5..
According to Buggy there is a secret floor even lower than lv.5. So far I don't believe it has been given any name, but fans call it lv.6 for convenience.