NEW YORK (July 15, 2026) — A team of researchers led in part by Christopher Gilbert , professor of anthropology at the CUNY Graduate Center and Hunter College, has confirmed the discovery of a previously unknown species of African monkey in the rainforests of the Democratic Republic of Congo (DRC), marking one of the most significant primate discoveries in decades.
The new species, Colobus congoensis , known locally as the Likweli , is only the fifth new monkey species identified in Africa in the past 75 years. The findings, published in PLOS One , are the culmination of years of international collaboration combining genetics, anatomy, field observations, and local ecological knowledge to establish the monkey as a distinct evolutionary lineage.
For Gilbert, the discovery builds on more than a decade of research in the Congo Basin. He also played a central role in confirming the discovery of the Lesula ( Cercopithecus lomamiensis ), another monkey species identified in the same region in 2012.
"When a potential new species is discovered, the evidence has to be overwhelming," said Gilbert. "We analyzed museum collections and comparative datasets, examining skulls, pelts, and skeletal anatomy alongside specimens from known African colobus monkeys. Those comparisons allowed us to demonstrate conclusively that Colobus congoensis represents a distinct species."
Gilbert led the anatomical analyses with longtime collaborator Eric Sargis , a Yale University professor and CUNY Graduate Center Ph.D. alumnus. They were joined by Julia Arenson, who was then a doctoral student at the Graduate Center. Arenson had assembled one of the most comprehensive comparative datasets on colobus monkey anatomy as part of her dissertation research, providing critical evidence that helped distinguish the new species from all other African colobus monkeys.
The team's anatomical research began in 2022 after field researchers recovered specimens that allowed detailed scientific comparisons. Using extensive collections from the Yale Peabody Museum and the American Museum of Natural History, along with Arenson's newly compiled database of skull measurements and Gilbert's comparative analyses of pelts and skeletal remains, the researchers established the formal anatomical diagnosis required to describe the species.
The discovery stems from a mystery that began in 2008, when researchers photographed an unusual monkey in the forests between the Lomami and Congo (Lualaba) rivers in east-central DRC. A clearer observation a decade later prompted an international investigation involving researchers from Florida Atlantic University, the Lukuru Wildlife Research Foundation, Yale University, the CUNY Graduate Center and Hunter College, Lomami National Park, and the Frankfurt Zoological Society.
Genetic analyses confirmed that C. congoensis belongs to the genus Colobus while revealing that it diverged from its closest known relative, Colobus satanas , approximately 4 to 5 million years ago. Anatomical evidence generated by Gilbert, Arenson, and their collaborators independently confirmed the species' distinctiveness.
The monkey is immediately recognizable by its glossy black coat, long cape-like fur, sweeping tail, and striking orange-cream facial markings. Weighing about 15 pounds, it is smaller than its closest relatives and possesses distinctive cranial, dental, and skeletal characteristics that separate it from every other known African colobus monkey.
The researchers also documented the species' unique vocalizations and worked closely with local communities to understand its distribution and behavior. Between 2018 and 2022, the team recorded just 114 sightings across an estimated range of approximately 1,700 square kilometers.
That limited distribution raises conservation concerns. The researchers propose that Colobus congoensis be classified as Endangered because of its restricted range, habitat loss, and hunting pressure. Most of its known habitat lies within Lomami National Park, making protection of the region critical for the species' survival.
"We continue to be reminded that the Congo Basin remains one of the world's last great frontiers for mammal discovery," said John A. Hart , first author of the study and a conservation scientist with the Lukuru Wildlife Research Foundation. "Even in regions that have been scientifically explored, entirely new species are still coming to light. This discovery reinforces how much biodiversity remains undocumented in the Central Congo Basin and how this region continues to reshape our understanding of primate evolution and conservation."
“This discovery is both exciting and deeply personal, highlighting the extraordinary biodiversity of my homeland and how much remains undocumented,” said Junior Amboko , co-corresponding author, a Ph.D. student in the Department of Biological Sciences in FAU’s Charles E. Schmidt College of Science and a National Geographic Explorer. “I was honored to name the species ‘Colobus congoensis,’ recognizing the Congo Basin’s remarkable natural heritage and, we believe, marking the first primate named after the Democratic Republic of Congo itself – underscoring both its global importance and local pride.”
The study was led by researchers from Florida Atlantic University and included collaborators from the Lukuru Wildlife Research Foundation, Yale University, the CUNY Graduate Center and Hunter College, Lomami National Park, and the Frankfurt Zoological Society.
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PLOS One
Animals
Likweli: A remarkable new species of Colobus monkey from the Lomami National Park, Democratic Republic of Congo
15-Jul-2026