Taxonomy, phylogeny and distribution of tamarins (genus Saguinus, Hoffannsegg 1807)

Abstract

The Callitrichinae are small bodied New World primates, including two of the most diverse groups of primates, the marmosets (genera Callithrix and Mico) and tamarins (genus Sa-guinus). So far, about 35 tamarin taxa have been described. The phylogenetic relationships within this subfamily and in particular the phylogeny of the six species groups of tamarins (Saguinus) and their position within the Callitrichinae is disputed. The first part of this thesis illuminates the phylogenetic relationships within the Callitrichinae on a broader scale. We sequenced 13 complete mitochondrial genomes of nearly all callitri-chine genera and Saguinus species groups. Based on our phylogenetic reconstructions, Sa-guinus branched off first among Callitrichinae, followed by Leontopithecus. Among the re-maining genera, Callimico is basal, and Mico and Cebuella form sister genera to the exclusion of Callithrix. The genus Saguinus is further divided into various, unexpectedly old lineages. We found much older and deeper phylogenetic splits between different species groups of Saguinus than between the different genera of marmosets. The S. nigricollis group split off from other tamarins in the late Miocene around 9.2 mya. The other species groups diverged between 5.3 and 7.3 mya. The taxonomic nomenclature of the different species groups should be revised and we recommend an elevation to generic level for at least the S. nigricollis species group. We bring our data together with the current standard of knowledge of Amazonian geology. Our data support a West-Amazonian origin and an eastward dispersal of the genus Saguinus. The second part goes more into detail by focusing on the S. nigricollis species group, which is the most diverse group and with its numerous taxa, subspecies and/or color variants and cryptic distribution areas surely one of the most complicate genera of New World primates. To further elucidate the phylogenetic relationships and the biogeographic history within this species group, and to contribute to a more reliable classification of its taxa, we sequenced the complete mitochondrial cytochrome b gene and the hypervariable region I of the D-loop. Therefore, we mainly used fecal samples from about 100 wild tamarins collected during two expeditions to the Peruvian Amazon, an area of high tamarin diversity. Most taxa of the S. nigricollis group form monophyletic clusters, which mainly originated in a single rapid radia-tion ~2.9 mya. S. fuscicollis and S. nigricollis appear as polyphyletic taxa, but we could identify various clusters, which are mainly consistent with differences in coat coloration. We could confirm most of the existing taxa as distinct entities and suggest species status for fus-cicollis, illigeri, lagonotus, leucogenys, nigricollis, nigrifrons, tripartitus and weddelli. Our genetic data do not support a separate status for melanoleucus and graellsi, but due to differences in fur coloration, we give them subspecies status. The species group most likely originated in western Amazonia and diversified during the decline of the Acre wetland and the formation of the Amazonian river system. The third part is bringing together the information on distribution areas, distribution limits and sympatry, obtained during our extant field surveys in the Peruvian Amazon, with the evidence of other field researchers and the current knowledge provided by museum speci-mens and historic reports. A detailed understanding of the range of the golden-mantle tamarin, Saguinus tripartitus, in Amazonian Peru and Ecuador is of particular relevance, not only because it is poorly known but also because it was on the basis of it s supposed sympatry with the saddleback tamarin (Saguinus fuscicollis lagonotus). A number of surveys have been carried out since 1988 in the supposed range of Saguinus tripartitus, in both Ecuador and Peru. Here we summarize and discuss these, and provide a new suggestion for the geo-graphic range of this species; that is, between the ríos Napo and Curaray in Peru, extending east into Ecuador. We also review current evidence for the distributions of Spix s black-mantle tamarin (S. nigricollis nigricollis), Graells black-mantle tamarin (S. n. graellsi) and the saddleback tamarin (S. fuscicollis lagonotus), which are also poorly known, and examine the evidence regarding sympatry between them.