The Lurker, the Slasher and the Leaper all make appearances in these new Dead Space: Extraction screens.

Previously, we've seen the Infector (gigantic manta-ray bats) Necromorph and not much else besides Slashers. Executive Producer Steve Papoutsis has promised that there will be new enemies for the Wii exclusive prequel to EA's flagship horror title — but he said players won't see the new Necromorphs 'til "later on in the game," which may be why we don't get to see them in these new screens:

For a handy list of the different types of Necromorph in Dead Space, check out this user-made list.