paraphyletic

In phylogenetics, a group of organisms is said to be paraphyletic (Greek para = near and phyle = race) if the group contains its most recent common ancestor, but does not contain all the descendants of that ancestor. Groups that do include all the descendants of the most recent common ancestor - are said to be monophyletic.Sometimes the term holophyletic is used instead of monophyletic. Technically these two terms are not equivalent: originally a monophyletic group was simply one including the most recent common ancestor of its members (Greek monos = one) and would thus be either monophyletic or paraphyletic in the modern sense; while a holophyletic group included all descendants of the most recent common ancestor (Greek holos = whole), thus being monophyletic in the modern sense. However, in actual practice monophyletic has lost this original meaning and has displaced holophyletic which has mostly dropped out of use.
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