Given the timescales involved in animal evolution and the difficulty of identifying new species as their first members emerge, there is no single species that could be said to have evolved most recently. Some animals, however, have populations that do not breed together and could be regarded as emergent species.
One example of a species that has recently begun to diverge is the Australian sea urchin Heliocidaris erythrogramma. According to Matt Walker, writing for the BBC, some of these urchins breed in summer, others in winter, and are thus behaviorally isolated from each other. Since the two populations do not breed with each other, genes are not able to flow between them. If both species survive, differences will inevitably accumulate on either side of what is now a species barrier.