Ensuring the demographic and genetic viability of small populations of threatened primates requires a range of management approaches. Here we describe a novel mixed in situ and ex situ management project that was developed to restore a population of the Critically Endangered northern muriqui Brachyteles hypoxanthus. This isolated population, located in Ibitipoca, Lima Duarte, Minas Gerais, Brazil, had declined to two adult males and would have gone extinct without intervention. A first attempt at in situ management in 2017 involved the translocation of a solitary female from another region, but this female did not associate or interact with the males and disappeared after 9 months. We thus initiated a second and ongoing ex situ management project that involved constructing a complex consisting of a large, open-air enclosure abutting a small patch of forest surrounded by an open area in the process of restoration, all of which is protected by electric fencing. The entire area within the fencing is called Muriqui House. The two Ibitipoca males and two solitary, wild females from another location were captured and released into the enclosed part of Muriqui House between March 2019 and January 2020 and into the forested part of Muriqui House in February 2020. The birth of an infant in this group in November 2020 and the acceptance by the group of a third female translocated from another area in January 2021 demonstrate the potential of this approach for the recovery of this isolated population, with positive implications for the conservation of the species.

Understanding how vegetation structure and floristic composition vary across landscapes is fundamental to understand ecological patterns and for designing conservation actions. In a patch-landscape approach, we assessed the β-diversity (q0 order – rare species, q1 order – common species, and q2 order – dominant species) of plants between forest patches and surveyed plots in Atlantic Forest patches located in the Pernambuco Endemism Centre, northeastern Brazil. Furthermore, we tested the influence of predictor variables linked to landscape (forest cover and edge density) and habitat (basal area), as well as the geographical distance between forest patches and plots on the β-diversity in each forest patch and plot. We measured and identified a total of 1,682 individuals (trees and lianas), corresponding to 248 species, 116 genera, and 56 families in 10 plots (50 × 2 m) from each forest patch. The β-diversity presented lower values for the Mata de Água Azul patch at a landscape scale (i.e., between forest patches) and Mata dos Macacos patch at a site scale (i.e., between plots) for all orders. Geographical distance positively influenced the β-diversity at the landscape scale, and higher turnover between plots (e.g., within forest patches) was positively associated with differences in geographical distance, edge density, forest cover, and basal area. Our results indicate the need to conserve forest patches distributed across a wide area (distant sites) that encompass different landscape contexts with different vegetation structures, in order to conserve greater floristic diversity.

Saimiri collinsi is used as an animal model in biotechnology research for conservation of species from the genus Saimiri. However, the development of biotechnologies depends on a proper knowledge of the sperm morphology to understand the basic aspects of sperm physiology, as potential male fertility depends on different cellular sperm structures. With this purpose, this study characterized the micromorphological and ultrastructural characteristics of squirrel monkeys (Saimiri collinsi) sperm using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). SEM electromyography revealed that a normal Saimiri collinsi sperm measures 71.7 ± 0.7 μm with lateral tail insertion, a paddle-shaped flattened head and an acrosome occupying most of the head. TEM also showed that the middle piece is characterized by a central 9 + 2 microtubule axoneme surrounded by nine dense fibres, and that the mitochondria were juxtaposed, forming the mitochondrial sheath. Here we provide the first micromorphological and ultrastructure description of S. collinsi sperm.

The Critically Endangered Peruvian yellow-tailed woolly monkey Lagothrix flavicauda was presumed to only occur in the tropical montane cloud forests between the Marañón and Huallaga rivers in northern Peru. Here we report the discovery of a population to the south of its previously known range, in the Región Junín. During September–December 2018 we carried out transect surveys to record large mammals present near the village of San Antonio in the district of Pampa Hermosa, at 1,287–2,015 m altitude. We recorded five primate species during transect surveys. Lagothrix flavicauda was seen four times, and appeared phenotypically distinct from populations to the north, with notable white patches above each eye and a reduced yellow patch at the end of the tail. The presence of L. flavicauda in Junín extends its known geographical range over 200 km southwards from the closest previously known population in the Huánuco region, and presents a unique opportunity for the conservation of this Critically Endangered species.

Lowland forests of western Amazonia contain the most species-rich primate communities in the Neotropics, which begs the question of what mechanisms operate to promote species coexistence. This study examines habitat occupancy and its relationship to phylogeny in a primate community in Amazonian Ecuador. First, as potential factors that shape community structure, we determined whether (1) mean height in the forest canopy differed among species; (2) within each species, habitat occupancy was disproportional to habitat availability; and (3) species diverged in habitat occupancy. We then tested hypotheses regarding ecological distance and its relationship to phylogenetic distance among species pairs within this community. We tested these hypotheses primarily with data derived from 15 censuses of primate species on two 100-ha plots in eastern Ecuador. In these censuses, we observed eight primate species over nearly 200 encounters. We observed larger species at greater heights in the forest canopy than smaller ones. Although they occupied habitat types at frequencies proportionate to their availability in the study area, species diverged in habitat occupancy. Although a clear relationship was not observed between phylogenetic and ecological distances among species pairs, this study suggests that ecological differences among the species in this community facilitate their coexistence.

In order to better comprehend the putative association between genotype Trypanosoma cruzi II and primates, an evaluation of the infection in free ranging primates and specimens born in captivity from different geographical areas, the Amazon and the Atlantic forest, was carried out. Seroprevalences of the T. cruzi infection among the primates was similar in both biomes (45·5% and 46%). The parasites were isolated from 8 and 4 different species of primates, respectively from the Amazon and Atlantic forest. Multi-locus enzyme electrophoresis (MLEE) typed the isolates from Amazon as zymodeme 1. Mini-exon gene analysis characterized all these isolates as T. cruzi I, the main genotype circulating in the region. In the Atlantic forest, primates infected with TCI and TCII, as well as a mixed infection (TCI and TCII), were detected. These findings prove that primates may maintain stable infections by both genotypes. Moreover, data show that T. cruzi can occur in a wide range of primate genera, independent of their social behaviour, niches or habitats. Considering the high seroprevalence and stability of T. cruzi infection among the primates, these animals play an important role in the maintenance of the parasite in nature.

Yasuni National Park and Biosphere Reserve in Ecuador's Amazon basin is home to the Huaorani and an area of high conservation value. As a result of oil development in the early 1990s, a road was constructed in the northern region of the Park. Three Huaorani communities have since been established in proximity to the road, two of them when the road was built, ten years prior to this study, and the third in a previously uninhabited area. This allowed for a natural experiment comparing harvest compositions across communities of different ages at one point in time. Harvest profiles suggest that the spider monkey Ateles belzebuth is facing local depletion near the two old communities and the howler monkey Alouatta seniculus may also be depleted near one of the old communities. That the two oldest communities still harvested a relatively high number of other vulnerable species is attributed to their use of the road to increase forest access. The spider monkey appears to be the first species to become depleted in persistently hunted areas.

The Guianas contain one of the largest single remaining tracts of undisturbed tropical rainforest in the world, but this forest and its fauna are facing increased threats. In the north of French Guiana both anthropogenic pressures and conflicts between settlements related to the use of natural resources are growing. Based on surveys in 17 forest sites we show that hunting pressure was the main factor determining current primate species richness, masking the effects of logging or forest type. Three of the larger species, the red howler monkey Alouatta seniculus, black spider monkey Ateles paniscus and tufted capuchin Cebus apella, were less abundant in hunted areas. In the areas around four settlements the harvested biomass of primates was low compared to other game species, but the harvests were close to or beyond the maximal sustainable thresholds for the red howler monkey and tufted capuchin. In French Guiana primates are either fully protected by law (the spider monkey and white-faced saki Pithecia pithecia), or their hunting is restricted to subsistence use (howler monkey, tufted capuchin and wedge-capped capuchin Cebus olivaceus). Most hunted meat is, however, destined for sale. Current conservation policy in French Guiana is limited to legal protection for some species and areas, and laws are poorly enforced. Although large areas of forest and its wildlife are protected simply by their remoteness, there is an increasingly urgent need for the legal protection of all primate species, and the establishment of large protected areas and efficient forest management schemes to minimize the impacts of logging and hunting.