autochthonic vs autochthonal

autochthonic and autochthonal both are adjectives.

Word	Noun	Adjective	Verb	Adverb
autochthonic	No	Yes	No	No
autochthonal	No	Yes	No	No

As adjectives, autochthonic and autochthonal are synonyms defined as:

Other synonyms of autochthonic include autochthonous, endemic, indigenous.

autochthonic (adjective)	autochthonal (adjective)
originating where it is found	originating where it is found