Douglas Harper's Etymology Dictionary
1827, from autochthon + -ic.
Wiktionary
a. existing where it was formed or born; native, aboriginal, indigenous
WordNet
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: autochthonal, autochthonous, endemic, indigenous]
Usage examples of "autochthonic".
In the old days before humans had migrated to the CY3O-CY3OB star system, the autochthonic population had worshiped a mountain deity named Yah, whose abode, the autochthons had explained, was the little mountain on which Herb Asher's dome had been erected.
Except that all the autochthonic goats had died out, and, along with them, the ritual.
I am one of the autochthonic goats that in former times was sacrificed to Yah.
There was nothing traditional, nothing archaic, nothing autochthonic in their poor art.
It is certain, I say, that, although I had made a start before, only from the occurrence of the Secession War and what it show’d me as by flashes of lightning, with the emotional depths it sounded and arous’d (of course, I don’t mean in my own heart only, I saw it just as plainly in others, in millions) -- that only from the strong flare and provocation of that war’s sights and scenes the final reasons-for-being of an autochthonic and passionate song definitely came forth.