What is "hystricomorpha"

The term Hystricomorpha (from Latin hystrix "porcupine" and Greek μορφή, morphē "form") has had many definitions throughout its history. In the broadest sense, it refers to any rodent (except dipodoids) with a hystricomorphous zygomasseteric system. This includes the Hystricognathi, Ctenodactylidae, Anomaluridae, and Pedetidae. Molecular and morphological results suggest the inclusion of the Anomaluridae and Pedetidae in Hystricomorpha may be suspect. Based on , these two families are treated here as representing a distinct suborder Anomaluromorpha.