Sciurus stramineus stramineus: No nuchal patch, dorsal colour usually brown heavily streaked anteriorly with grey, sometimes yellowish grey posteriorly; head distinctly darker than rest of dorsum, with brownish tones; venter dark brown, sometimes with tinge of grey. see James L. Patton, Ulyses F. J. Pardinas, and Guillermo D'Elia (2015): Mammals of South America, Volume 2, Rodents. The University of Chicago Press, Chicago and London.