Source : Webster's Revised Unabridged Dictionary (1913)

Autochthonal \Au*toch"tho*nal\, Authochthonic
\Au`thoch*thon"ic\, Autochthonous \Au*toch"tho*nous\, a.
   Aboriginal; indigenous; native.

Source : WordNet®

autochthonal
     adj : originating where it is found; "the autochthonal fauna of
           Australia includes the kangaroo"; "autochthonous rocks
           and people and folktales"; "endemic folkways"; "the
           Ainu are indigenous to the northernmost islands of
           Japan" [syn: {autochthonic}, {autochthonous}, {endemic},
            {indigenous}]