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We observed a zoo-housed group of cotton-top tamarins (Saguinus oedipus) before and after a bout of severe targeted aggression directed towards two of its members. The aggression was so severe and repeated that the zoo personnel was forced to remove the two victims and the main aggressor. In the tense period that preceded removal, the tamarins showed increased aggression, a steeper and linear dominance hierarchy, and reduced post-conflict reconciliation compared to the period following removal. In contrast, affiliative interactions such as grooming and peaceful food transfers did not differ in the two periods of observations. Patterns of reciprocity also remained stable. These results highlight the flexibility of tamarin social relationships and provide useful information for managing captive colonies and improving animal welfare. [ABSTRACT FROM AUTHOR]

Anthropogenic climate change (CC) is affecting a wide range of ecosystems and species, modifying current biodiversity patterns, and increasing the risk of extinction for many species. To address this threat, identifying, managing and protecting climate refugia has been suggested as an approach to incorporate CC into systematic conservation planning. In this study, we applied a detailed Ecological Niche Modeling (ENM) approach with the Maximum Entropy Algorithm to assess the potential effects of CC on the distribution of climatic suitability for Saguinus leucopus and Saguinus oedipus. These two species were investigated to identify climate refugia, and to assess the effectiveness of Protected Areas (PAs). Correlative models were generated with presence records, and bioclimatic variables describing recent (~ 2000) and future (~ 2050) climates, with data from two Global Circulation Models (GCMs) under two Representative Concentration Pathways (RCP), describing moderate (RCP 4.5) and extreme (RCP 8.5) climate change scenarios. For both species, moderate and extreme CC scenarios resulted in expansion of climatic suitability. Refugia models, through the overlapping of GCMs, indicated that 88% and 82% of the recent climate suitability may act as refugia for S. leucopus and S. oedipus. Greater variation was found coming from GCM selection than from RCPs. Regions of exposure to climatic novelties were identified for both species. Results suggest that climate refugia for these species are critically under-protected, as only 5.7% and 9.9% respectively, coincide with current PAs. Finally, PAs that are playing an important role in preserving climate refugia for these species are mentioned. [ABSTRACT FROM AUTHOR]

Early primate evolution is connected to the efficient exploitation of the terminal branch habitat. Mammals that forage in this habitat constantly encounter flexible thin branches that bend under the weight of the animals and thus form steeply inclined and declined supports. This study was aimed to gain insight into how cotton-top tamarins - a previously proposed modern analogue for a hypothetical stage in early primate evolution with prehensile autopodia - meet the specific functional demands when navigating thin, branch-like supports of different orientation. X-ray motion analysis was combined with synchronous single limb substrate reaction force measurements to discern limb mechanical adjustments. Previously reported gait parameter adjustments were confirmed for moderate support orientations, but on the steepest inclines and declines kinematic discontinuities were observed. These are interpreted to emphasize the functional roles of the forelimbs (net-braking role) and hind limbs (net-propulsive role) already established for level and moderately inclined supports. Tensile forces were exerted by the forelimbs on the steepest inclines and by the hind limbs on the steepest declines (head-first descents). Even though non-specialized small mammals have also been shown to successfully negotiate similar supports, prehensility offers advantages for foraging on thin, steeply inclined and declined terminal branches. Thus, the evolution of prehensile autopodia in small early primates likely has enhanced the exploitation of the terminal branch habitat. [ABSTRACT FROM AUTHOR]

Infant carrying is common in primates and may be the second most costly activity related to reproduction, after lactation. In cooperative breeding groups of callitrichids, all group members carry and care for twin infants. Previous studies have described the costs of infant carrying in terms of body mass loss and reduced locomotor capability. However, infant carrying may also influence travel speed, an important potential cost because slower speed may handicap foraging, energetic budgets, and predator avoidance. We evaluated the impact of infant carrying on the travel speed of 27 adult and 9 subadult cotton-top tamarins ( Saguinus oedipus) of both sexes in large outdoor enclosures. We compared carrier speed to speed when not carrying during the 10 weeks after nine births. Subadult tamarins, which have a lower body mass than adults do, moved faster than adults when not carrying. We found no difference between the mean speeds of subadults and adults while carrying. However, the speed of carriers decreased as infant mass increased, and the slope of this negative relationship was more pronounced in subadult carriers. For every 80 g of extra mass load (the body mass of newborn twins), adults reduced their speed by 6 % and subadults by 19 % relative to noncarrying speed. We also observed a reduction in speed while carrying two infants in adult tamarins as carrying time increased. Our results contribute to an understanding of the costs of infant carrying, and serve to emphasize the importance of cooperative breeding systems in coping with these costs. [ABSTRACT FROM AUTHOR]

The cell line B95-8 releases Epstein–Barr virus (EBV) with high titres of transforming activity and is widely used as a model in cancer research and virology. There are, however, controversial reports about the species of origin, cell line stability and karyotype. To address these questions, B95-8 chromosomes were analysed by chromosome sorting and painting by multicolour fluorescence in-situ hybridization. Reciprocal painting was performed between B95-8, ‘wildtype’ New World monkey and human chromosomes. Saguinus oedipus was revealed as the species of origin. A further five cell-line-specific marker chromosomes, resulting from translocations, deletions and an insertion were found. Although human chromosome 6 or 13 homologues were always involved in these rearrangements, co-hybridization of an EBV-specific DNA probe did not reveal site-specific hybridization to marker chromosomes or at translocation breakpoints. The multicolour probe set described here will be of special value for further evolutionary studies in New World monkeys. [ABSTRACT FROM AUTHOR]