This biozone is characterized by the presence of Pristerognathus polyodon and its other subspecies Pristerognathus baini and Pristerognathus vanderbyli. Pristerognathus fossils are usually found associated with those of Diictodon.
This biozone is defined by the co-occurrence of Pristerognathus polyodon and its subspecies, Pristerognathus baini and Pristerognathus vanderbyli, alongside Diictodon fossils.