Why all the monkeys?
Why are so many new primate species being found? Such a simple question has some intricate and interrelated answers. For starters, a renewed focus on conservation means that more scientists are spending more time in more places where they are likely to encounter new animals. It doesn’t hurt that defining a new species means more funding and recognition for the area in which the animals live and the organization that found them. Additionally, a shift in how the scientific establishment defines species means that the classification is broader; some believe it is easier for scientists to gain new species status for groups of animals that previously wouldn't have been eligible.
This is in response to the new mangabey found not long ago, as well as a host of other species.
They point out some encouraging trends. Research focussed on areas of high richness tends to find new species. Finding new species tends to bring more conservation efforts, which protects all the species.
The article also indicates that some new species are described for conservation, rather than biological purposes. I guess that's probably true, but I don't know.
Species are tricky. I'll step on John Wilkins' toes by weighing on species concepts, but he's all the way over in Australia, so what can he do? Species concepts are a mess, and there's a simple reason. Species are a bit of a fiction. There's some sort of thing that can reasonably be called a species, but it's all about the differences between two things, and there's no magic distance, and it isn't even clear what the axis is we're supposed to be measuring on. In large part, that's what Darwin was arguing in the Origin. Species are varieties by a different name.
Some say it's about mating incompatibility. That's OK, but what about species which can't mate in the wild, or don't as a practical matter, but which can have viable offspring. And don't get me started on asexual organisms.
So people have started liking the Evolutionary Species Concept, that a species is a group of organisms on a unique evolutionary trajectory. That's fine, but is still pretty subjective.
Is this new monkey a new species? Probably, for the right definition.
What I really want to point out is that good surveys of underexplored areas are vital if we're going to catalog the diversity of life. Call them species, varieties, operational taxonomic units, whatever. We need to find them before the forest gets cut down.