A melanistic reef manta cruising over a textured sand flat on a tropical reef. Melanistic Reef Mantas despite their pitch-black appearance are the exact same species as the the standard black and white reef manta. Their difference in apperance is refered to as a 'Colour Morph'. Melanistic Mantas are completely black due to a higher proportion of darker pigments in their skin. Manta rays are the only species of sharks and rays shown to possess melanism. Up to 40% of some populations of reef mantas are melanistic while other populations not a single manta will carry the trait. There appears to be no obvious advantage or disadvantage for melanistic mantas.