Opinions from R. M. Nowak 1999
- 'Abrocomidae belongs to Octodontoidea'
- 'Agoutidae belongs to Cavioidea'
- 'Anomaluridae belongs to Anomaluromorpha'
- 'Anomaluromorpha belongs to Sciurognathi'
- 'Aplodontidae belongs to Protrogomorpha'
- 'Bathyergidae belongs to Bathyergomorpha'
- 'Bathyergomorpha belongs to Hystricognathi'
- 'Bibymalagasia belongs to Eutheria'
- 'Capromyidae belongs to Octodontoidea'
- 'Castoridae belongs to Castorimorpha'
- 'Castorimorpha belongs to Sciurognathi'
- 'Caviidae belongs to Cavioidea'
- 'Cavioidea belongs to Caviomorpha'
- 'Caviomorpha belongs to Hystricognathi'
- 'Chinchillidae belongs to Chinchilloidea'
- 'Chinchilloidea belongs to Caviomorpha'
- 'Ctenodactylidae belongs to Ctenodactylomorpha'
- 'Ctenodactylomorpha belongs to Sciurognathi'
- 'Ctenomyidae belongs to Octodontoidea'
- 'Dasyproctidae belongs to Cavioidea'
- 'Dinomyidae belongs to Cavioidea'
- 'Dipodidae belongs to Dipodoidea'
- 'Dipodoidea belongs to Myomorpha'
- 'Echimyidae belongs to Octodontoidea'
- 'Erethizontidae belongs to Erethizontoidea'
- 'Erethizontoidea belongs to Caviomorpha'
- 'Geomyidae belongs to Geomyoidea'
- 'Geomyoidea belongs to Myomorpha'
- 'Glirimorpha belongs to Sciurognathi'
- 'Heptaxodontidae belongs to Octodontoidea'
- 'Heteromyidae belongs to Geomyoidea'
- 'Hydrochoeridae [misspelled as Hydrochaeridae] belongs to Cavioidea'
- 'Hystricidae belongs to Hystricomorpha'
- 'Hystricognathi belongs to Rodentia'
- 'Hystricomorpha belongs to Hystricognathi'
- 'Muridae belongs to Muroidea'
- 'Muroidea belongs to Myomorpha'
- 'Myocastorinae was reranked as the family Myocastoridae and belongs to Octodontoidea'
- 'Myomorpha belongs to Sciurognathi'
- 'Myoxidae belongs to Glirimorpha'
- 'Octodontidae belongs to Octodontoidea'
- 'Octodontoidea belongs to Caviomorpha'
- 'Pedetidae belongs to Anomaluromorpha'
- 'Petromuridae belongs to Phiomorpha'
- 'Phiomorpha belongs to Hystricognathi'
- 'Plesiorycteropodinae was reranked as the family Plesiorycteropodidae and belongs to Bibymalagasia'
- 'Protrogomorpha belongs to Sciurognathi'
- 'Sciuridae belongs to Sciuromorpha'
- 'Sciurognathi belongs to Rodentia'
- 'Sciuromorpha belongs to Sciurognathi'
- 'Thryonomyidae belongs to Phiomorpha'