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.
References in periodicals archive ?
However, this assemblage is not resolved as monophyletic in the present study, and there is evidence that these cells occur outside the grasses, in Joinvillea (Smithson, 1957), so the presence of fusoid cells may be a plesiomorphy of the grass family.
adhesive tubes, ciliary patterns, cuticular sculpture, reproductive anatomy), and recognition of plesiomorphy is often difficult.