The wikipedia article says "While animals have lived in the cave for 5.5 million years, not all of them arrived simultaneously. One of the most recent animals r

The wikipedia article says "While animals have lived in the cave for 5.5 million years, not all of them arrived simultaneously. One of the most recent animals recorded is the cave's only species of snail, Heleobia dobrogica, which has inhabited the cave for slightly more than 2 million years."