Author's note: these pages were written some years ago. I am not planning to update them. For a more current coverage, see the Palaeos website (to which many links on these pages point to anyway. More info here

graphic © Darren Abbey

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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