Stephen Nash's titi as on the underside of the species' limbs. It is 28 inches long, although 17 inches is taken up by the titi's tail. Stephen Nash's titi Stephen Nash's titi ("Plecturocebus stephennashi"), also known as just Nash's titi or Stephen Nash's monkey, is a species of titi, a type of New World monkey, endemic to the eastern bank of the Purus River in Brazil. It was discovered by Marc van Roosmalen in 2001 when local fishermen brought specimens to his breeding center. It was described in 2002. It was named in honor of Stephen D. Nash, an illustrator for Conservation International,
Caquetá titi titi and white-tailed titi except that it does not have a white forehead bar, nor does it have the white hands and feet of the ornate titi. It also has a red beard. It has 22 chromosome pairs (not counting the sex chromosomes), with a diploid chromosome number of 2n=46. In the paper describing the species, the authors recommend that the species be classified as critically endangered by the International Union for Conservation of Nature (IUCN). According to the authors' estimate, the population size of the species may be fewer than 250 adult animals. It lives in forests fragmented by