plesiomorphy


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Related to plesiomorphy: Cladistic analysis, Plesiomorphic

plesiomorphy

(plē′sē-ə-môr′fē, plē′zē-)
n. pl. plesiomor·phies
An evolved character or trait that is shared by some or all members of a phylogenetic group and their common ancestor but is not unique to that group. A segmented spinal column is a plesiomorphy of mammals, being present as well in other groups such as fishes, reptiles, amphibians, and birds.

ple′si·o·mor′phic adj.