Paraphyletic Taxa
The Paraphyletic taxon is
a group of organisms in which the most recent common ancestor of all those
organisms and some, but not all, of that ancestor's descendents
are included. Paraphyletic taxa are recognised in Linnean
and evolutionary systematics but not in
cladistics.
Illustration: the Class Reptilia gave rise to mammals and birds,
but neither mammals nor birds are included under Reptilia.
Examples: Invertebrates, Amphibia,
Reptilia, Dinosauria
(excluding birds), Gymnosperma, etc.
graphic (top) from 
Systematics page
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page history
page uploaded 13 November 1998
modified 28 November
and again 18 December