Atlantic titi barrier such as a river and are thus completely genetically isolated from one another). Distinctions between each of the "Callicebus" subspecies are based on coat color. The evolution of these coat colors is termed metachromism. The pigments are produced by melanocytes which deposit the pigments into the medulla of growing hair so that the hair grows with the color of that distinct pigment. The characteristic pigment of the "Callicebus" is eumelanin (dark brown or black) found in the iris, skin, and hair (usually on the forehead, crown and tail). Atlantic titis are opportunistic feeders. In other words, they eat based
Retinal pigment epithelium Retinal pigment epithelium The pigmented layer of retina or retinal pigment epithelium (RPE) is the pigmented cell layer just outside the neurosensory retina that nourishes retinal visual cells, and is firmly attached to the underlying choroid and overlying retinal visual cells. The RPE was known in the 18th and 19th centuries as the pigmentum nigrum, referring to the observation that the RPE is dark (black in many animals, brown in humans) ; and as the tapetum nigrum, referring to the observation that in animals with a tapetum lucidum, in the region of the tapetum lucidum the RPE is not pigmented.