Carabus violaceus purpurascens or Megodontus violaceus purpurascens is considered by some authors (Rautenstrauch) as a separate species, 'Megondontus purpurascens', which occurs in the Western part of Europe.
In Turin et al., 'purpurascens' is considered as a subspecies of Megodontus violaceus or Carabus violaceus.