Order Primates Author Wilson, Don E. Author Reeder, DeeAnn text 2005 The Johns Hopkins University Press Baltimore Mammal Species of the World: a Taxonomic and Geographic Reference (3 rd Edition), Volume 1 111 184 book chapter 0-8018-8221-4 10.5281/zenodo.7316519 Callicebus (Callicebus) dubius Hershkovitz 1988 Callicebus (Callicebus) dubius Hershkovitz 1988 , Fieldiana Zool., n. s., 55: 66 . Type Locality: Brazil , east bank of R . Purus, opposite Lago Ayapua, ca. 4°20' S , 62°00' W , according to Hershkovitz (1990). Vernacular Names: Hershkovitz' Titi . Distribution: Brazil , Ituxi River or the Mucuim River, east to the Madeira River south of Humaita, and west to the Purus River ( van Roosmalen et al., 2002 ). Conservation: CITES – Appendix II; IUCN – Vulnerable. Discussion: Subgenus Callicebus . C. cupreus species group. A synonym of cupreus according to Groves (2001 c ) , who thought it was a colour morph, but shown to be consistently different, with a distinct geographic distribution by van Roosmalen et al. (2002) .