Phylogenetic relationships of the callitrichinae (Platyrrhini, primates) based on beta(2)-microglobulin DNA sequences

The phylogenetic relationships of callitrichine primates have been determin ed by DNA sequence analyses of exons 1, 2, and 3 of the beta(2)-microglobul in gene. Parsimony, distance, and maximum Likelihood analyses of ca. 900 ba se pairs of 21 tare, representing all callitrichine genera, indicated that Saguinus was the most basal offshoot. Within Saguinus, S. fuscicollis appea red as the first divergent Lineage followed by an unresolved trichotomy for med by S. mystax/S. imperator, S. midas/S. bicolor, and S. oedipus. A secon d callitrichine lineage was formed by Leontopithecus; each of the three spe cies studied showed identical nucleotide sequences. Callimico appeared as t he sister taxon of Callithrix/Cebuella. Genetic distances within this latte r group were very small, although a stronger association between Cebuella a nd species of the Callithrix argentata group was observed. The inclusion of Cebuella in the genus Callithrix is suggested. These studies indicated tha t tamarins are more plesiomorphic than marmosets in agreement with the phyl etic dwarfism hypothesis. (C) 1999 Wiley-Liss, Inc.