Molecular phylogeny of the genus Saguinus (Platyrrhini, Primates) based on the ND1 mitochondrial gene and implications for conservation

Biogeography of the marmosets and tamarins (Callitrichidae)

The marmosets and tamarins, Family Callitrichidae, are Neotropical primates with over 60 species and subspecies that inhabit much of South America. Although callitrichids exhibit a remarkable widespread distribution, attempts to unravel their biogeographic history have been limited by taxonomic confusion and the lack of an appropriate statistical biogeographic framework. Here, we construct a time-calibrated multi-locus phylogeny from GenBank data and the callitrichid literature for 38 taxa. We use this framework to conduct statistical biogeographic analyses of callitrichids using BioGeoBEARS. The DIVAj model is the best supported reconstruction of biogeographic history among our analyses and suggests that the most recent common ancestor to the callitrichids was widespread across forested regions c. 14 Ma. There is also support for multiple colonizations of the Atlantic forest region from the Amazon basin, first by Leontopithecus c. 11 Ma and later by Callithrix c. 5 Ma. Our results show support for a 9 million year old split between a small-bodied group and large-bodied group of tamarins. These phylogenetic data, in concert with the consistent difference in body size between the two groups and geographical patterns (small-bodied tamarins and large-bodied tamarins have an unusually high degree of geographic overlap for congeners) lend support to our suggestion to split Saguinus into two genera, and we propose the use of distinct generic names; Leontocebus and Saguinus, respectively.

Anatomic study of the collateral branches of the abdominal aorta of primate species Saguinus niger

Saguinus niger is a primate of the family Callitrichidae, with a geographical distribution limited to northern Brazil, Guyanas, Suriname and Venezuela, where it inhabits rainforests along the coast. Three adult females from the Paragominas Bauxite Mine--PA were used, donated to the Laboratory of Animal Morphology Research (LAMR) of the Federal Rural University of Amazonia. These animals had died of natural causes. The arterial system was filled with latex, and the animals were fixed in 10% formalin. Afterwards, the abdominal aorta and its collateral branches were dissected. The arrangement of the abdominal aorta branches in this species showed a similar arrangement as domestic animals but differing in the formation of the coeliac trunk. The coeliac trunk originates from the abdominal aorta, and from this trunk, we found the hepatic, left gastric and splenic arteries, where the origin of these vessels was variable. These arteries originate from the coliac trunk or a common trunk originating from the coeliac trunk, a characteristic not described in other species. The other branches of the abdominal aorta from S. niger did not show great differences in origin when compared to other species.