The creatures in the Ice Wall.

During the scene where Manny, Sid, Diego, and the baby are in the ice cave theres that part where Sid gets seperated from the other three, and as hes wandering about he stumbles across a series of animals frozen in the ice wall and at one point hes observing these four animals lined in the ice wall which include an oversized amoeba, an eel, an otter like creature, and ??? cant identify the last one. Anyways I read this old wikipedia article on the movie(Its been edited) and it states that the creatures are actually real life extinct animals, except for the amoeba. Does anybody know what animals these were?