Pronunciation: ple-si-o-MOR-fik

Etymology: Plesiomorphic is derived from two Greek roots that mean near or close to (plisiazo, πλησιάζω) and form (morfi, μορφή). The reference is to a character that is close to the primitive condition.

Plesiomorphic means primitive character. In the example below of a cladogram of therapsid evolution, note the primitive or plesiomorphic characters (in blue) and the apomorphic characters (in red).

Plesiomorphic characters in blue; apomorphic characters of three extant Therian lineages in red.
Text material © 2002 by Steven M. Carr. Image material © 1993 by Hickman et al.

By Jack R. Holt. Last revised: 01/02/2009