ABSTRACT
This chapter discusses Phylogenetic conceptions of species are very similar in some ways to the classifications of the older logic of division. Species concepts based upon the phylogeny of the groups of organisms are called phylogenetic, but there are several phylospecies concepts and there are several sub-versions of them in turn. It is something of a misconstrual to think that there are only two phylospecies concepts besides the Hennigian account. The Hennig account is fundamentally a biospecies concept. Hennig himself accepted that species were reproductively isolated, and the criteria used for identifying the relevant phylogenetic edges of the cladogram are simply those of the biospecies. All the diagnostic concepts rely upon a species being the "terminal taxon" in a cladogram. There are many other conceptions that their authors refer to, or which are referred to by others, as "phylogenetic" conceptions of species.
