 The delination between Neoepiblemidae and Dinomyidae has historically been unclear; with some genera (such as "Phoberomys" and "Eusigmomys") having varying taxonomic placement.A 2017 study found "Phoberomys" to be part of the group, While "Eusigmomys" to be part of Dinomyidae.Fossils of the family were found in the Colhuehuapian to Huayquerian Pinturas, Sarmiento, Santa Cruz, Cerro Bandera and Ituzaingó Formations and Colhué Huapí Member of Argentina, the Solimões Formation of Brazil, the Pebas Formation of Peru and the Urumaco Formation of Venezuela.