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 (Torquatus) regulus Thomas 1927 Callicebus (Torquatus) regulus Thomas 1927 , Ann. Mag. Nat. Hist., ser. 9, 19: 510 . Type Locality: Brazil , state of Amazonas , Fonte Boa, right bank of upper Rio Solimoes. Vernacular Names: Red-headed Titi . Distribution: Brazil , between Rios Javari/Solimoes and Rio Jurua. Conservation: CITES – Appendix II; IUCN – Lower Risk (lc). Discussion: Subgenus Torquatus . Separated as a species from C. torquatus by van Roosmalen et al. (2002) .