Oxymycterus delator is endemic to the Cerrado and the Caatinga, and has been recorded in the Brazilian states of Bahia, Ceará, Goiás, Mato Grosso, Mato Grosso do Sul, Minas Gerais, Paraná, Piauí, São Paulo, and Tocantins, and in the Distrito Federal; and in the Paraguayan departments of Canindeyú and Paraguarí (Emmons 1999, Hoffmann et al. 2002, Andrade et al. 2004, Bonvicino et al. 2005, 2008, 2012, 2014, Bruna et al. 2010, Ribeiro et al. 2010, Carmignotto and Aires 2011, Owen 2013, Gurgel-Filho et al. 2015, Oliveira and Gonçalves 2015, Stumpp et al. 2016). It has been indicated that the species occurs also in the Chaco biome (Carmignotto et al. 2012), but we are not aware of reported specimens that support this notion. D’Elía et al. (2008) noted that in Paraguay the species is restricted to the Oriental Region (east of the Paraguay River), where areas with Chaco’s physiognomy are absent and, instead, isolated patches of Cerrado can be found (Owen 2013).

The red list of the IUCN ver. 3.1 assigned the category “Least Concern” to Oxymycterus delator (see Patterson et al. 2008). The species was not included in the official list of threatened species of Brazil (ICMBIO-MMA 2016).