title: Durotrigensia
text: # Durotrigensia
  
  Durotrigensia is a genus of ammonites (Ammonitida) in the perisphinctoid family Parkinsoniidae.
  
  Durotrigensia is sometimes considered a subgenus of Parkinsonia and is related also to Oraniceras and Okribites.
  
  These cephalopods lived during the Bajocian stage of the Middle Jurassic some 170 to 164 million years ago.
  
  ## Description
  
  These large to giant ammonites have sharp and finely ribbed inner whorls and smooth outer whorls, without tubercles or lappets.
  
  