Dinofact #62
All known pachycepahlosaurs, except for two species, Ferganocephale and Stenopelix lived during the late Cretaceous. Ferganocephale, which can be traced back to the middle Jurassic, lacks some features on its teeth distinctive to all other known pachycephalosaurs, and Stenopelix, traced to the early Cretaceous, is based on a partial skeleton lacking the skull, which some scientists have now reclassified as a ceratopsian. With both outlying species of pachycephalosaurs sometimes considered nomen dubiums, it is possible that all known pachycephalosaurs lived during the late Cretaceous period.
Source: Wikipedia [1], [2], [3]













