au·toch·tho·nous 
(ô-tŏkthə-nəs) also au·toch·tho·nal (-thə-nəl) or au·toch·thon·ic (ô′tŏk-thŏnĭk)
(ô-tŏkthə-nəs) also au·toch·tho·nal (-thə-nəl) or au·toch·thon·ic (ô′tŏk-thŏnĭk)adj.
1. Originating or formed in the place where found; indigenous: autochthonous rocks; an autochthonous people; autochthonous folk tales. See Synonyms at native.
2. Ecology Native to or produced within a system: an autochthonous species; algae that provide an autochthonous source of nutrients in a lake.
au·tochthon·ism, au·tochtho·ny n.
au·tochtho·nous·ly adv.