The eumelanosome is large (~0.9 x 0.3 [micro]m) and ellipsoidal with a highly ordered glycoprotein matrix that is integral to the production of the black or brown coloured eumelanin pigments, whereas the red or yellow pheomelanins are produced within smaller and spherical (~0.7 [micro]m diameter)
pheomelanosomes that are composed of a loosely aggregated and disordered glycoprotein matrix (Sturm et al., 2001).