The Xenothrix, Antillothrix, Paralouatta, Carlocebus, Lagonimico, and Tremacebus genera of Callicebinae are extinct.

[6] Due to the previous classification before independent definition, P. brunneus is now thought to be endemic to Brazil.

[7] The Brown Titi do not differ too dramatically from their relatives, however, they are notably unique in their combination of morphological features.

Individuals of this species possess a grey agouti colouration on the crown of the head and dorsal parts, a bright red-brown venter, an almost completely black tail with a pale tip, and light yellow colouration of the hair on the cheeks with bright red-brown hair on the sides of the face.

[9] Brown titi's are viviparous animals, and produce a single offspring after a 5-month pregnancy period.

[1] Construction of housing, roads, architecture or even agriculture all contribute to habitat loss for the brown titis.

Other detrimental threats include transportation such as roads and utility/service lines where they may possibly be killed when traversing across, dams and water management use, agriculture and biological resource use - hunting and trapping.