find a mate. While the life expectancy of most species is unclear, the members of the genus Cheracebus may live for up to 12 years in the wild, while members of the P. moloch group have been known to live for more than 25 years in captivity. Classification The number of known species of titis has doubled in recent years, with eight, P. stephennashi, P. bernhardi, P. caquetensis, P. aureipalatii, P. miltoni, P. urubambensis, P. grovesi, and P. parecis being described from the Amazon basin since 2000. Furthermore, the most recent review uses the phylogenetic species concept (thereby not recognizing the concept of subspecies) rather than the 'traditional' biological species concept. The classification presented here is therefore very different from the classifications used twenty years ago. The naming rights to a recently discovered species were auctioned off (with the funds going to a nonprofit organization), and the winner was the online casino GoldenPalace.com, as reflected in both the common and scientific name of P. aureipalatii. While this typically is a highly unusual event in scientific classification, the possibility of naming a species of titi in exchange for a sizable donation to a nonprofit foundation was also presented a few years before, resulting in P. bernhardi being named after Prince Bernhard of the Netherlands. Historically, titis were monogeneric and formed the genus Callicebus Thomas, 1903. Owing to the great diversity found across titi monkey species, a new genus-level taxonomy was recently proposed that recognises three genera within the subfamily Callicebinae; Cheracebus Byrne et al. (2016) for the species of the torquatus group (Widow titis); Callicebus Thomas, 1903, for species of the Atlantic Forest personatus group; and Plecturocebus Byrne et al. (2016) for the Amazonian and Chaco titis of the moloch and donacophilus groups. Genus Plecturocebus P. donacophilus group White-eared titi, Plecturocebus donacophilus Rio Beni titi, Plecturocebus modestus Rio Mayo titi, Plecturocebus oenanthe Ollala brothers's titi, Plecturocebus olallae White-coated titi, Plecturocebus pallescens Urubamba brown titi, Plecturocebus urubambensis P. moloch group Baptista Lake titi, Plecturocebus baptista Prince Bernhard's titi, Plecturocebus bernhardi Brown titi, Plecturocebus brunneus Ashy black titi, Plecturocebus cinerascens Parecis titi, Plecturocebus parecis Hoffmanns's titi, Plecturocebus hoffmannsi Alta Floresta titi, Plecturocebus grovesi Milton's titi, Plecturocebus miltoni Red-bellied titi, Plecturocebus moloch Vieira's titi, Plecturocebus vieirai Toppin's titi, Plecturocebus toppini Madidi titi, Plecturocebus aureipalatii Chestnut-bellied titi, Plecturocebus caligatus Caquetá titi, Plecturocebus caquetensis Coppery titi, Plecturocebus cupreus White-tailed titi, Plecturocebus discolor Hershkovitz's titi, Plecturocebus dubius