• species definitions;
  • phylogenetic species concept; subspecies

The way we view the Species category in Primates, as in other animals, especially other vertebrates, has been going through a revolution over the past 20 years or so. Much is wrong with the idea that we can define species according to whether or not they are “reproductively isolated”: this concept, the so-called Biological Species Concept, has never offered any guidelines in the case of allopatric populations; this has now been shown to be simply wrong. Although other ways of looking at species – the Evolutionary, Recognition, Cohesion and Genetic Species Concepts – have all provided particular insights, the only proposal to offer a repeatable, falsifiable definition of species is the Phylogenetic Species Concept. This has been criticised for increasing the number of species to be recognised, although it is not clear why this should be a problem: indeed, it tells us that the world is far richer in biodiversity than we had conceived. Am. J. Primatol. 74:687-691, 2012. © 2012 Wiley Periodicals, Inc.