Symplesiomorphy

Symplesiomorphy meaning shared old form) is the persistence of ancestral (primitive) traits in different clades .
Found on http://www.enchantedlearning.com/subjects/dinosaurs/glossary/

Symplesiomorphy

In cladistics, a symplesiomorphy or symplesiomorphic character is an ancestral trait shared by two or more taxa. A plesiomorphy refers to the ancestral trait on its own, usually in reference to another, more derived trait. A symplesiomorphic trait is also shared with other taxa that have an earlier last common ancestor with the taxa under consider...
Found on http://en.wikipedia.org/wiki/Symplesiomorphy
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