Pronunciation: sin-A-po-mor-fi

Etymology: Synapomorphy has the prefix syn (συν), which is Greek for plus. The reference is to a derived character (apomorphy) that is added or shared.

A symapomorphy is the condition when organisms share derived or apomorphic character states. Synapomorphic characters are evidences of monophyletic descent.

The cladogram below shows the character hair is derived and defines a monophyletic clade (cat + kangaroo).

Within this taxon set, hair is a shared derived character (synapomorphy) of therians
that indicates a close relationship of marsupial and placental mammals. © 2004 S.M. Carr

By Jack R. Holt. Last revised: 01/03/2009