Dasymys robertsii is recorded in swampy wetland areas. It has reddish-brown fur on the back and dull gray fur underneath. HMW 2017 treats it separately from D. incomtus sensu stricto, citing differences in allozymes, chromosomes, and skull measurements.
Its fur is long, soft, and shaggy, reddish brown on the back and dull gray underneath.
Its habitat is swampy wetland. HMW 2017 reports that it is mainly crepuscular and diurnal.
An extinction-risk assessment has not been added yet.