au·tap·o·mor·phy 
(ô-tăpə-môr′fē)
(ô-tăpə-môr′fē)n. pl. au·tap·o·mor·phies
An evolved character or trait that is unique to a single species or group within a larger phylogenetic group. Speech is an autapomorphy of humans among primates.
au·tapo·mor′phic adj.