The titis, or titi monkeys, are New World monkeys of the subfamily Callicebinae, which contains three extant genera: Cheracebus, Callicebus, and Plecturocebus. This subfamily also contains the extinct genera Miocallicebus, Homunculus, and Carlocebus.
Titi monkeys live in South America, from Colombia, Ecuador and Peru, east through Brazil, and south to Bolivia and northern Paraguay.
Description
Depending on species, titis have a head and body length of , and a tail, which is longer than the head and body, of .
Titis are monogamous, mating for life. The female bears a single young after about a five-month gestation. Twins occur rarely, having been documented in only 1.4% of all births in captive groups of Plecturocebus moloch. While the second infant usually does not survive, cases where neighbouring groups have adopted infants are known, suggesting that twins may be reared successfully under certain circumstances. Often it is the father who cares for the young, carrying it and bringing it to the mother only for nursing. Fathers tend to engage in more grooming, food-sharing, inspecting, aggression and playing with infants than mothers. The young are weaned after 5 months and are fully grown after two years. After three or more years, they leave their family group in order to 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.
upright|thumb|A pair of white-eared titis (P. donacophilus) entwining tails.
thumb|335x335px|A Madidi titi monkey (Plecturocebus aureipalatii).
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.
- 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