[6][7] These last changes were made with few arguments to support the changes and were apparently influenced by the increasing use of the so-called phylogenetic species concept of Cracraft, which seeks to define species as the "smallest diagnosable cluster of individual organisms within which there is a parental pattern of ancestry and descent.

The recent discovery of a diploid number of 16 for the black titi, Cheracebus lugens, in Brazil suggested that (with the previously known 2n=20 of another, unidentified population of C. torquatus) there are at least two species in this complex.

The tail is blackish mixed with some reddish hairs with hands and feet whitish or dark brown.

This pelage contrasts in all of the subspecies with a band of white hair which extends upward from the chest and follows the neck, prolonging itself to the ears.

[14][16] The collared titi is seen most frequently in well-developed, tall forest with a closed canopy, usually over terra firme, but not exclusively so.