Phillip Hershkovitz described in 1990 a new subspecies of titi monkey from the Atlantic rainforest, which he named in honour of an associate of the Field Museum the Barbara Brown’s titi monkey, Callicebus personatus barbarabrownae.
The holotype of the new subspecies was collected In Lamarao, Bahia, Brazil. According to Hershkovitz, this new species is the same as the illustration of “Callithrix gigot” published in 1823 by Spix. However, the original description of Callithrix gigot (Spix 1823) should refer to the earlier described melanochir, and therefore gigot should be seen as a junior synonym of that species. This has generally been followed by later authors.
The actual distribution of C. barbarabrownae is not yet completely clear, but the species is probably restricted to the coastal highlands of the north-central part of the state of Bahia, Brazil, between the Rios Paraguaçú, just north of the city of Salvador, and Itapicurú. The western limits to its range are unknown but probably, at least historically, the middle reaches of the Rio São Francisco.