Dero digitata is reddish in color, small to medium-sized. Pink pigment is concentrated in the head segments and branchial organ. The prostomium has minute hairs. Dorsal bundles start from segment IV, with one hair and one needle per bundle, although some specimens have two hairs and two needles in segment VII. Ventral setae range from 2 to 4 per bundle. There are five pairs of ciliated gills.