versão On-line ISSN 0121-3709
The Callicebus are small primates (800-1,200 g) amply distributed in South America. The taxonomy of the genus has been discussed by various authors. Recently Defler (2004), based on work by Hershkovitz (1990) recognized two groups of species in Colombia: Callicebus cupreus and Callicebus torquatus. Because of high karyotypic variability in the genus, karyotypes constitute an important systematic character. Wide differences in chromosome number are well-correlated with species groups that have been described for the genus based on morphological and biogeographical characteristics. Characteristic of the species in the cupreus group are high chromosome numbers (2n=44 for C. c. ornatus and 2n=46 for C. c. discolor and C. c. caquetensis). In contrast, the C. torquatus species group has low chromosome numbers (2n=16 for C. lugens and 2n=20 for Callicebus torquatus and C. t. lucifer and possibly C. t. medemiwhich has not yet been studied genetically). Based on our cytogenetic finds from cell cultures from 11 specimens from different populations of Callicebus, we have found that our karyological data are concordant with the species groups and permit us to differentiate C. ornatus, C. caquetensis and C. discolor as independent species in the cupreus group. In the torquatus group there were no detectable differences between a "lugens" phenotype from Florencia, Caquetá and a C. t. lucifer from the Colombian trapezium (both were 2n=20), increasing the distribution of the species with that karyotype in the Colombian Amazon. Although initially we supposed that C. lugens (2n=16) was not present in the Colombian Amazon, the discovery of a C. lugens (2n=16) in the Matacaña Zoo strongly suggests the presence of this species in the Colombian Orinoco, although this must be confirmed with field studies. Based on our results a discussion of the evolutionary process in chromosomes is presented for this monogamous, territorial primate genus and some hypotheses regarding the evolution of this group are proposed.
Palavras-chave : karyotype; chromosome evolution; Callicebus; cytotaxonomy.