Aspect of two species that are equivalent as a consequence of , that is, aspects that are homologous.

Shared characters can either either be unique to a taxon (and therefore represent a shared derived character) or instead may be shared with other, related taxa (and therefore represent a shared ancestral character).

In either case, shared characters are . The distinction is in how far back one has to go to reach the ancestor in which the shared character first arose. Only if one need not leave a specific clade to reach that ancestor is the character described as a shared derived character.