I thought about an Australopithecus analogy, but thought readers might grasp the idea of bringing back the wooly mammoth as it's currently in the news (along with the dodo). Apart from that, I've lost track of whether omicron is a straight derivative of delta, or if they have a shared common ancestor - which would make it more like the mammoth analogy ;)

Actually, according to this article in Science, it looks more like they shared a common ancestor....so, mammoth rather than Homo erectus.