CHROMOSOMAL SIMILARITIES AND DIFFERENCES BETWEEN TAMARINS, LEONTOPITHECUS AND SAGUINUS (PLATYRRHINI, PRIMATES)

The karyotypes of two taxa of genus Leontopithecus (rosalia and chryso melas) are studied. Their G-, C- and NOR-banding patterns are compared with those of representatives of the genus Saguinus to determine chro mosomal similarities and differences between the two genera and thus c ontribute to explaining phylogenetic relations between the tamarins. L eontopithecus, like the Saguinus, presents 2n = 46, 14 autosomes plus the Y acrocentric and 30 autosomes plus the X biarmed. No chromosomal rearrangement distinguishes the karyotypes of the representatives of g enus Leontopithecus or genus Saguinus. The two genera are distinguishe d from each other by a paracentric inversion and pericentric inversion s on at least four pairs of acrocentric autosomes, displacing the NORs of the small short arms in Leontopithecus to the proximal region of t he long arms in Saguinus or vice versa. The tamarins are also distingu ished by the distribution of noncentromeric constitutive heterochromat in. The data obtained indicate that the two tamarin genera are closely related chromosomally, suggesting that they probably originated from the same ancestral branch. (C) 1997 Wiley-Liss, Inc.