The genome of the endangered dryas monkey provides new Insights into the evolutionary history of the vervets

Genomic data can be a powerful tool for inferring ecology, behaviour and conservation needs of highly elusive species, particularly when other sources of information are hard to come by. Here we focus on the dryas monkey, an endangered primate endemic to the Congo Basin with cryptic behaviour and possibly less than 250 remaining individuals. Using whole genome data we show that the dryas monkey represents a sister lineage to the vervet monkeys and has diverged from them at least 1 million years ago with additional bi-directional gene flow 590,000 – 360,000 years ago. After bonobo-chimpanzee admixture, this is the second reported case of gene flow that most likely involved crossing the Congo River, a strong dispersal barrier. As the demographic history of bonobos and dryas monkey shows similar patterns of population increase during this time period, we hypothesise that the fluvial topology of the Congo River might have been more dynamic than previously recognised. As a result of dryas monkey - vervet admixture, genes involved in resistance to the simian immunodeficiency virus (SIV) have been exchanged, possibly indicating adaptive introgression. Despite the presence of several homozygous loss-of-function mutations in genes associated with reduced sperm mobility and immunity, we find high genetic diversity and low levels of inbreeding and genetic load in the studied dryas monkey individual. This suggests that the current population carries sufficient genetic variability for the long-term survival of this species. We thus provide an example of how genomic data can directly improve our understanding of elusive species

Lesula: A New Species of Cercopithecus Monkey Endemic to the Democratic Republic of Congo and Implications for Conservation of Congo’s Central Basin

In June 2007, a previously undescribed monkey known locally as “lesula” was found in the forests of the middle Lomami Basin in central Democratic Republic of Congo (DRC). We describe this new species as Cercopithecus lomamiensis sp. nov., and provide data on its distribution, morphology, genetics, ecology and behavior. C. lomamiensis is restricted to the lowland rain forests of central DRC between the middle Lomami and the upper Tshuapa Rivers. Morphological and molecular data confirm that C. lomamiensis is distinct from its nearest congener, C. hamlyni, from which it is separated geographically by both the Congo (Lualaba) and the Lomami Rivers. C. lomamiensis, like C. hamlyni, is semi-terrestrial with a diet containing terrestrial herbaceous vegetation. The discovery of C. lomamiensis highlights the biogeographic significance and importance for conservation of central Congo’s interfluvial TL2 region, defined from the upper Tshuapa River through the Lomami Basin to the Congo (Lualaba) River. The TL2 region has been found to contain a high diversity of anthropoid primates including three forms, in addition to C. lomamiensis, that are endemic to the area. We recommend the common name, lesula, for this new species, as it is the vernacular name used over most of its known range

Complex Evolutionary History With Extensive Ancestral Gene Flow in an African Primate Radiation

Understanding the drivers of speciation is fundamental in evolutionary biology, and recent studies highlight hybridization as an important evolutionary force. Using whole-genome sequencing data from 22 species of guenons (tribe Cercopithecini), one of the world's largest primate radiations, we show that rampant gene flow characterizes their evolutionary history and identify ancient hybridization across deeply divergent lineages that differ in ecology, morphology, and karyotypes. Some hybridization events resulted in mitochondrial introgression between distant lineages, likely facilitated by cointrogression of coadapted nuclear variants. Although the genomic landscapes of introgression were largely lineage specific, we found that genes with immune functions were overrepresented in introgressing regions, in line with adaptive introgression, whereas genes involved in pigmentation and morphology may contribute to reproductive isolation. In line with reports from other systems that hybridization might facilitate diversification, we find that some of the most species-rich guenon clades are of admixed origin. This study provides important insights into the prevalence, role, and outcomes of ancestral hybridization in a large mammalian radiation

To conserve African tropical forests, invest in the protection of its most endangered group of monkeys, red colobus

Forest loss and overhunting are eroding African tropical biodiversity and threatening local human food security, livelihoods, and health. Emblematic of this ecological crisis is Africa's most endangered group of monkeys, the red colobus (genus Piliocolobus). All 17 species, found in forests from Senegal in the west to the Zanzibar archipelago in the east, are threatened with extinction. Red colobus are among the most vulnerable mammals to gun hunting, typically disappearing from heavily hunted forests before most other large-bodied animals. Despite their conservation status, they are rarely a focus of conservation attention and continue to be understudied. However, red colobus can act as critical barometers of forest health and serve as flagships for catalyzing broader African tropical forest conservation efforts. We offer a plan for conservation of red colobus and their habitats and discuss conservation and policy implications.Additional authors: Deo Kujirakwinja, Barney Long, W. Scott McGraw, Russell A. Mittermeier, Thomas T. Struhsake

Impact of Hunting on the Lesula Monkey (Cercopithecus lomamiensis) in the Lomami River Basin, Democratic Republic of the Congo

Understanding the impact of hunting on wildlife is necessary to protect biodiversity in remote, endangered ecosystems, where rural communities depend on bushmeat as sources of food and income. Unsustainable hunting has led to a major decline in mammal population densities across Africa, especially for ungulates and primates. The objectives of this study were to (1) quantify the impact of hunting on lesula (Cercopithecus lomamiensis), a semiterrestrial and poorly known monkey in the Democratic Republic of the Congo, and (2) assess the species’ relative abundance in the context of its behavioral ecology and local hunting practices. We compared the relative abundance of lesula to prey species preferred by hunters using data collected from camera trap surveys (5,960 days) and primate vocalization surveys (n = 174) and assessed species-specific hunting pressure in the buffer zone using data collected from surveillance patrols (2,255 km), hunter follows (n = 16), and semistructured interviews (n = 21). We found that the abundance of terrestrial mammal and primate species was negatively impacted by hunting in the buffer zone, but the abundance of lesula appeared relatively similar throughout its range. Our results suggest that the relative tolerance of lesula in the buffer zone was associated with its ecological niche and the specific behavior of local hunters. Lesula is a threatened, endemic monkey of the Congo Basin rainforest, and this study provides data to enable its continuous monitoring and long-term population management. Some primate populations, such as lesula, may be able to persist under specific conditions despite being subject to high hunting pressure

Lesula: A New Species of <i>Cercopithecus</i> Monkey Endemic to the Democratic Republic of Congo and Implications for Conservation of Congo’s Central Basin

<div><p>In June 2007, a previously undescribed monkey known locally as “lesula” was found in the forests of the middle Lomami Basin in central Democratic Republic of Congo (DRC). We describe this new species as <i>Cercopithecus lomamiensis</i> sp. nov., and provide data on its distribution, morphology, genetics, ecology and behavior. <i>C. lomamiensis</i> is restricted to the lowland rain forests of central DRC between the middle Lomami and the upper Tshuapa Rivers. Morphological and molecular data confirm that <i>C. lomamiensis</i> is distinct from its nearest congener, <i>C. hamlyni</i>, from which it is separated geographically by both the Congo (Lualaba) and the Lomami Rivers. <i>C. lomamiensis,</i> like <i>C. hamlyni,</i> is semi-terrestrial with a diet containing terrestrial herbaceous vegetation. The discovery of <i>C. lomamiensis</i> highlights the biogeographic significance and importance for conservation of central Congo’s interfluvial TL2 region, defined from the upper Tshuapa River through the Lomami Basin to the Congo (Lualaba) River. The TL2 region has been found to contain a high diversity of anthropoid primates including three forms, in addition to <i>C. lomamiensis</i>, that are endemic to the area. We recommend the common name, lesula, for this new species, as it is the vernacular name used over most of its known range.</p></div

Juvenile coloration.

<p><i>Cercopithecus hamlyni</i>, captured east of Kisangani, DRC (left), and <i>Cercopithecus lomamiensis</i>, captured near Obenge, DRC (right). White nose stripe is variably present in juvenile <i>C. hamlyni</i> from the Kisangani region. Photos by John Hart.</p

Captive <i>Cercopithecus lomamiensis</i>.

<p>Left: Adult male, Yawende, DRC. Photograph by M. Emetshu. Right: Subadult female, Opala, DRC. Photograph by J. A. Hart.</p

Distribution of anthropoid primates of the Tshuapa–Lomami–Lualaba (TL2) region¹.

<p>Distribution of anthropoid primates of the Tshuapa–Lomami–Lualaba (TL2) region¹.</p