"Diversity of Cebus species from the southern distribution of the genus"

NIEVES, MARIELA; MUDRY, MARTA D.

"Molecular Population Genetics, Evolutionary Biology and Biological Conservation of Neotropical Primates"

Nova Science Publishers

Lugar: New York; Año: 2016; p. 115 - 134

Taxonomists recognize different species and subspecies within the genus Cebus (capuchin monkeys, caiararas and macaco-prego) but classifications have been controversial and continuously revised. Relatively recently, evolutionary cytogenetic and molecular genetics studies using other molecular markers have suggested alternative classifications. The distinctive cytogenetic feature of Cebus is its conspicuous heterochromatic extracentromeric regions distributed along the whole karyotype. These are considered good markers for taxonomic diagnosis. The detection of specific mitochondrial haplotypes and morphological variation are also useful tools in phylogenetic, evolutionary and taxonomic studies. C. nigritus and C. cay naturally distributed in Northern Argentina, represent the southernmost geographic distribution of Cebus. These species show phenotypic variations mostly regarding the color of the body pelage with a highly homologous karyotype, although easily distinguishable from each other. Our aim in this chapter is to provide a better understanding of the variability within capuchin monkeys through the analysis of evolutionary cytogenetics, genome size estimations, geometric morphometrics and molecular genetics data. We studied 275 individuals (C. cay and C. nigritus) of which 44 were new specimens. The thirty-two new C. cay did not show any of the chromosomal reorganizations previously described. The analysis of C-band variability and frequency of polymorphisms allowed us to identify a species-specific pattern. We also detected connections between the three observed morphotypes and the geographic origin at the intraspecific level. One (P1) was associated with the Paraguayan C. cay with one heterochromatin variation pattern. A second (P2) was related to C. cay individuals from Salta, Bolivia, Peru with a different heterochromatin pattern. The third (P3) corresponded to C. nigritus specimens with a third heterochromatin pattern. We also detected a significant variability in genome size among the C. cay?s samples in agreement with the molecular genetics and geometric morphometrics analyses. Variations in skull morphologic patterns support the differentiation between C. nigritus and C. cay as well as the differentiation among Northwest Argentina, Southern Bolivia and Paraguay forms. In summary, our findings of Cebus cay and C. nigritus provide a pattern of diversity associated with the limits of this genus?s distribution. We propose a more holistic interpretation for understanding the present day diversity of these species in the context of the evolutionary history of the Cebus genus.