CHROMOSOMAL RELATIONSHIPS AND PHYLOGENETIC AND CLUSTERING ANALYSES ONGENUS CALLITHRIX, GROUP ARGENTATA (CALLITRICHIDAE, PRIMATES)

The karyotypes of three species of marmosets of the Callithrix argenta ta group (C. argentata, C. humeralifera and C. chrysoleuca) were studi ed. Comparisons were made among species and with the previously descri bed karyotypes of C. emiliae, C. mauesi(argentata group) and C. jacchu s (jacchus group). Two chromosome rearrangements differentiate the arg entata (2n = 44) and jacchus (2n = 46) groups: a fusion or fission and a paracentric inversion. The argentata group is also characterized by the addition of large amounts of distal constitutive heterochromatin (CH) in some chromosomes, while the jacchus group shows mainly centrom eric heterochromatin. The five species of the argentata group differ i n the amount or location of the distal CH. Interspecific differences w ere converted to a Basic Data Matrix (BDM), that was submitted to phen etic and cladistic analyses. For cladistic analyses C. jacchus was the outgroup. The results agree with morphological and geographical data.