A new monkey species has been discovered, providing more evidence for speciation.

Juvenile lesulas

speciation: Genetic changes sometimes accumulate within an isolated segment of a species, but not throughout the whole, as that isolated population adapts to its local conditions. Gradually it goes its own way, seizing a new ecological niche. At a certain point it becomes irreversibly distinct—that is, so different that its members can't interbreed with the rest. Two species now exist where formerly there was one. Darwin called that splitting-and-specializing phenomenon the "principle of divergence." It was an important part of his theory, explaining the overall diversity of life as well as the adaptation of individual species.

Remarkable new monkey discovered in remote Congo rainforest

The lesula is apart of the Cercopithecini family, which are commonly referred to as guenons. It's most similar to the owl-faced monkey (Cercopithecus hamlyni), which is also found in the region. But the lesula sports a lighter coat and has unique calls. Genetic testing, furthermore, proves the species are distinct from each other and have likely been separated for a few million years, probably by impassable rivers.