Hystricomorpha

Hystricomorpha is a group of rodents that has been defined in many different ways over time. The name comes from Ancient Greek words for "porcupine" and "form." In the broadest sense, it includes any rodent (except dipodoids) that has a special kind of skull structure called a hystricomorphous zygomasseteric system. This group includes animals like the Hystricognathi, Ctenodactylidae, Anomaluridae, and Pedetidae.

Recent studies using both molecules and physical features suggest that including Anomaluridae and Pedetidae in Hystricomorpha might not be correct. According to a reference from Carleton & Musser in 2005, these two families are now considered part of a different suborder called Anomaluromorpha.

Classification

The modern idea of Hystricomorpha groups together gundis and hystricognath rodents. There is good support from looks and genes for this grouping. If this is correct, it changes how we think about Sciurognathi.

Hystricomorph rodents first showed up in South America during a time called the Eocene. They may have traveled there by rafting across the Atlantic from Africa. This is still being studied and discussed by scientists.

Families

This list shows groups of rodents called Hystricomorpha. It comes from studies by scientists who looked at ancient rodents and found new ways to group them. Some of these groups are no longer considered valid, and some are extinct, marked with a symbol "†".

The main group is called Suborder Hystricomorpha and includes several families such as:

• Superfamily Ctenodactyloidea
  • †Chapattimyidae
  • Ctenodactylidae – gundis
  • Diatomyidae – Laotian rock rat
  • †Tamquammyidae
  • †Yuomyidae
• Hystricognathiformes
  • †Tsaganomyidae
  • Hystricognathi – true hystricognaths
    • †Baluchimyinae
    • Hystricidae – Old World porcupines
    • Phiomorpha
      • Bathyergidae – blesmols
      • †Bathyergoididae
      • †Diamantomyidae
      • Heterocephalidae – naked mole-rats
      • †Kenyamyidae
      • †Myophiomyidae
      • Petromuridae – dassie rat
      • †Phiomyidae
      • Thryonomyidae – cane rats
    • Caviomorpha – New World hystricognaths
      • Superfamily Cavioidea
        • Caviidae – cavies, capybaras, and guinea pigs
        • †Cephalomyidae
        • Cuniculidae – pacas
        • Dasyproctidae – agoutis and acouchis
        • Dinomyidae – pacarana
        • †Eocardiidae
        • †Neoepiblemidae
      • Superfamily Chinchilloidea
        • Abrocomidae – chinchilla rats
        • Chinchillidae – chinchillas and viscachas
      • Superfamily Erethizontoidea
        • Erethizontidae – New World porcupines
      • Superfamily Octodontoidea
        • Capromyidae – hutias
        • Ctenomyidae – tuco-tucos
        • Echimyidae – spiny rats
        • †Heptaxodontidae – giant hutias
        • Myocastoridae – nutria
        • Octodontidae – degus and relatives