†family Protoptychidae Tullberg 1899 (rodent)
Mammalia - Rodentia - Protoptychidae
Parent taxon: Protrogomorpha according to A. E. Wood 1958
See also Hay 1902 and McKenna and Bell 1997
Sister taxa: Akmaiomys, Floresomys, Ischyromyoidea, Jimomys, Laredomyidae, Marfilomys, Meliakrouniomys, Pseudoparamys, Sciuravidae, Texomys
Subtaxa: Presbymys Protoptychus
Ecology: ground dwelling herbivore
Distribution:
• Eocene of United States (4: California, Utah, Wyoming collections)
Total: 4 collections each including a single occurrence