The Hypermelanistic mutation causes an increase in black pigmentation resulting from a high quantity of melanophores. This mutation is not well studied so the genetic inheritance is unknown, it originates from Central American boas and is prevalent in Nicaraguan boas.
Although similar in appearance to anerythristic boas, they are distinctive due to the faint reds and oranges observed in their body coloration. Melanophores (black pigmentation) are located above the color-containing pigment cells such as xanthophores (yellow pigments), erythrophores (red pigments), and leucophores (white pigments). When melanophores are in high quantity little light is able to penetrate beneath the black pigmentation and is instead short-wavelength light is reflected. Thus the animals have little coloration.