With regard to fur color, Bolivian samples are
consistently Ochraceous-orange dorsally, with a slightly paler
venter. Few specimens are slightly paler, with mixed blocks of
grayish and golden fur (Fig. 6). On the other hand, adult and
juvenile M. simus are Tawny, Russet, or Cinnamon-brown
dorsally, and Ochraceous-tawny or Buckthorn-brown on the
venter—all consistently darker than M. midastactus (Fig. 6).