Color and color pattern are formed by pigments within chromatosomes located beneath the cuticle in both Heptacarpus pictus and H. paludicola. The exoskeleton
of these shrimp contains no conspicuous pigmentation. When the cuticle is removed from the underlying tissues, it is transparent with only a slight amber tint. Body
regions without chromatosomes are transparent or only slightly opaque. Chromatosomes occur within the hypo-dermis just beneath the cuticle, deep in muscular tissues,
and around internal organs. Body parts without chromatosomes are translucent, and the chromatosomes of deeper tissues show through to the surface. In both species, 4 basic chromatosome types are recognizable by light microscopy: red-white, red, yellow
and red-yellow (Table 1)