phylogenetic species concept (PSC) The concept of a species as an irreducible group whose members are descended from a common ancestor and who all possess a combination of certain defining, or derived, traits (see apomorphy). ... "phylogenetic species concept." A Dictionary of Biology. .
Or
The biological species concept has its limitations (although it works well for many organisms and has been very influential in the growth ofevolutionary theory). ... In thisexample, Ensatina salamander lineages A and B are separate species.Each has a common ancestor that individuals of other species do not.
