autochthonal vs basal

autochthonal

adj
  • existing where it was formed or born; native, aboriginal, indigenous 

basal

adj
  • Basic, elementary; relating to, or forming, the base, or point of origin. 

  • In a phylogenetic tree, being a group, or member of a group, which diverged earlier. The earliest clade to branch in a larger clade. 

  • Associated with the base of an organism or structure. 

  • Of a minimal level that is necessary for maintaining the health or life of an organism. 

noun
  • base, bottom, minimum 

  • Any basal structure or part 

How often have the words autochthonal and basal occurred in a corpus of books? (source: Google Ngram Viewer )