Who is Dionysia from Tales from Shakespeare and what is their importance?

Dionysia, Cleon's wife, is the woman with whom Pericles leaves his infant daughter to raise. Over the course of the tale, Dionysia becomes uncharacteristically jealous of Marina's loveliness, intelligence and talents because she outshines her own daughter. As a result, Dionysia plots the murder of Pericles' child.