plesiomorphic

adjective2

1. •
   Sharing a character state with an ancestral clade; primitive.

   • [T]he cockroach Polyphaga may represent a condition more plesiomorphic than in other Dictyoptera, but it could as well be paedomorphic, and therefore more derived than in other Dictyoptera [72]. — 2000
2. •
   Plesiomorphous.