primitive

adjective

(L. primitivus: the first one [in date], first-born) Describes a character state that is present in the common ancestor of a clade. A primitive character state is inferred to be the original condition of that character within the clade under consideration. For example, `presence of hair` is a primitive character state for all mammals, whereas the `hairlessness` of whales is a derived state for one subclade within the Mammalia.