VOUCHER MATERIAL: El Diamante: 1 adult female (MUSM 39281); see table 23 for measurements.
IDENTIFICATION: We consulted descriptions and measurements of Nectomys rattus provided by Hershkovitz (1944, as Nectomys squamipes melanius), Voss et al. (2001, as Nectomys melanius), Bonvicino and Weksler (2015), and Chiquito et al. (2017). No subspecies are currently recognized in Nectomys rattus (Bonvicino and Weksler, 2015; Chiquito et al., 2017). Nectomys rattus is distinguished from other species in the genus by the following combination of characteristics: dorsal fur grayish brown; venter fur pale gray; hind feet lacking hypothenar pads; forefeet with distinct rudiment of thumb with nail; tail scaly but moderately haired; lacrimals contacting the maxillary bone; interparietal much wider than long; and dorsolateral exposition of the exoccipital reduced (Bonvicino and Weksler, 2015; Chiquito et al., 2017). Our specimen conforms to previous descriptions of the species, and its measurements fall within the range of size variation previously documented.
REMARKS: Our single specimen was captured in a cultivated area. Lareschi and Velazco (2013) reported the mite Gigantolaelaps goyanensis from our specimen.