In
phylogenetics, a
synapomorphy is a shared
derived character or
trait state that distinguishes a
clade from other organisms. In other words, it is an
apomorphy shared by members of a
monophyletic group, and thus assumed to be present in their
most recent common ancestor. The word synapomorphy, coined by German entomologist
Willi Hennig, is derived from the
Greek words ,
syn = shared; ,
apo = away from; and ,
morphe = shape.