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| Colobus congoensis, known locally as “likweli,” has a dramatic black face with pinkish-orange lips. Photo Credit: Daniel Rosengren |
Scientific Frontline: Extended "At a Glance" Summary: Colobus congoensis
The Core Concept: Colobus congoensis is a newly discovered, distinct species of monkey endemic to the rainforests of the Democratic Republic of the Congo, characterized by its mostly black fur and striking orange facial patches.
Key Distinction/Mechanism: Anatomically and acoustically distinct from other African colobus monkeys, this species is smaller (approximately fifteen pounds) with sleek, light-reflecting fur, large folded ears, and unique, resonant roaring calls. Genetic evidence indicates it diverged from its closest relative, Colobus satanas, approximately four to five million years ago.
Major Frameworks/Components:
- Genetic Lineage: DNA analysis confirmed its membership in the Colobus genus and revealed a deep evolutionary split from its west-central African relatives.
- Anatomical Diagnosis: Extensive cranial, dental, and pelt comparisons with historical museum specimens validated its unique physical characteristics within the colobine lineage.
- Acoustic Ecology: Bioacoustic analysis demonstrated that its vocalizations possess a distinctly different acoustic structure compared to related Colobus species.
- Biogeographical Isolation: The species is naturally isolated by river systems between the Lomami and Congo rivers, restricting it to an unusually small range of roughly 1,700 square kilometers.
Branch of Science: Primatology, Evolutionary Biology, Taxonomy, and Conservation Biology.
Future Application: Continued ecological monitoring of Colobus congoensis will inform targeted conservation strategies and habitat protection policies within the Congo Basin, while further genetic studies could clarify broader primate evolutionary timelines.
Why It Matters: This discovery underscores the undocumented biodiversity of the central Congo Basin and emphasizes the critical need to protect the Lomami National Park region from ongoing habitat loss and hunting pressures, as the species is already recommended for Endangered status on the IUCN Red List.
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| Junior Amboko (left), co-corresponding author, FAU doctoral student and a National Geographic Explorer, and Mardoché B. Koko, co-author, working in the field in the Lomami National Park. Photo Credit: Courtesy of Florida Atlantic University |
In the rainforests of the Democratic Republic of Congo (DRC), scientists have identified a previously unknown species of African monkey—one of the rarest discoveries in modern primatology.
Named Colobus congoensis and known locally as “Likweli,” the monkey, which is mainly black with striking orange face patches, is only the fifth new monkey species identified in Africa in the last seventy-five years. Hidden within a remote region of the Congo Basin, the species remained undocumented despite decades of scientific exploration in Central Africa.
The mystery of this new species began with an unexpected sighting in 2008, when researchers captured a partially obscured photograph of the monkey. A decade later, researchers encountered the animal again and obtained a much clearer image. That discovery sparked further investigation into the elusive primate.
Now, new genetic, anatomical, and acoustic analyses have confirmed that the monkey represents a distinct evolutionary lineage that diverged from its closest known relative four to five million years ago. The findings, published in PLOS One, also suggest the species may already be at risk because of its limited range, habitat loss, and hunting pressure.
The discovery was made by an international team of scientists from Florida Atlantic University, the Lukuru Wildlife Research Foundation, Yale University, the City University of New York, Lomami National Park, and the Frankfurt Zoological Society.
The mysterious monkey was found in the remote interfluve between the Lomami and Congo (Lualaba) Rivers in east-central DRC, one of Central Africa’s most biologically significant regions.
“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.”
Draped in glossy black fur with cape-like shoulders, a long, sweeping tail, and a vivid orange-cream patch around the mouth and nose, C. congoensis has a striking, mask-like appearance unlike any other known colobus monkey. Smaller than related colobus monkeys—weighing about fifteen pounds—it is distinguished by sleek, light-reflecting fur and dramatic facial features created by long, black facial hairs and large, folded ears. White perianal markings further distinguish this species.
The discovery of C. congoensis also emphasizes the scientific importance of the Lomami National Park and its buffer zone in the DRC, which previously yielded another major primate discovery in 2012 by several members of this research team: the lesula (Cercopithecus lomamiensis).
“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 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.”
Genetic analyses confirmed that C. congoensis belongs to the genus Colobus but also revealed an unexpected evolutionary connection.
“The discovery of Colobus congoensis is reshaping our understanding of African monkey evolution,” said Kate Detwiler, Ph.D., senior and corresponding author and an associate professor of biological sciences in FAU’s Charles E. Schmidt College of Science. “Its closest known relative is Colobus satanas, found more than 1,200 kilometers away in west-central Africa. Yet our genetic evidence shows the two species diverged roughly four to five million years ago, marking one of the oldest known evolutionary splits within the Colobus lineage.”
Anatomical analyses played an instrumental role in confirming C. congoensis as a distinct species and establishing the physical characteristics that set it apart from other African colobus monkeys.
“We compared the skulls and pelts of C. congoensis with other species of African colobines, which underscored how unique this new species is,” said Julia L. Arenson, Ph.D., co-author and a postdoctoral associate at the Yale Institute for Biospheric Studies, who had assembled an extensive collection of skeletal data related to her Ph.D. thesis on colobus monkeys. “At the same time, despite being much smaller in body size, we also demonstrated that it shares features of the teeth, skull, and face with Colobus to the exclusion of other African colobines.”
The cranial and dental findings corroborated the genetic evidence and helped researchers establish the formal anatomical diagnosis required to validate the species.
“To name a new species, you have to be able to prove it,” said Christopher Gilbert, Ph.D., co-author and an anthropology professor with the City University of New York Graduate Center and Hunter College. “We used extensive museum collections, including specimens housed at the Yale Peabody Museum and the American Museum of Natural History, and comparative datasets to compare the skulls and pelts with known African colobus monkeys. This robust pool of information allowed us to quickly and conclusively confirm C. congoensis as a new species.”
The newly identified primate is not only genetically and anatomically distinct from other African colobus monkeys but is further distinguished by its vocalizations. Its deep, resonant roaring calls resemble those of related Colobus species but possess a distinct acoustic structure.
Researchers also incorporated local ecological knowledge to better understand the species’ distribution and behavior, speaking with residents and hunters across villages in the Lomami National Park’s buffer zone. Only eight villages recognized the species or could accurately describe it. Local communities referred to the monkey as “Likweli” and “kasaba nkoni,” the latter meaning “the branch shaker,” and described it as elusive and rarely seen.
Between 2018 and 2022, researchers recorded 114 sightings across an estimated range of just 1,700 square kilometers—an unusually small range for colobus monkeys. C. congoensis appears naturally isolated by rivers and forest barriers, and it is dependent on scattered upland forest patches in the Congo Basin.
Even as the species enters the scientific record, researchers warn it may already be at risk. Because of its extremely limited range, small population size, growing hunting pressure, and ongoing habitat loss, scientists are proposing C. congoensis be classified as Endangered on the IUCN Red List. Most of its known habitat lies within Lomami National Park, making protection of the region critical to the species’ survival.
“The discovery of Colobus congoensis is both a scientific triumph and a sobering reminder that some of Earth’s rarest creatures may vanish before the world even knows they exist,” said Detwiler.
Published in journal: PLOS One
Authors: John A. Hart, Junior D. Amboko, Julia L. Arenson, Emma R. Horton, Kathryn F. Coates,Jean-Pierre I. Kapale, Mardoché B. Koko, Terese B. Hart, Christopher C. Gilbert, Eric J. Sargis, and Kate M. Detwiler
Source/Credit: Florida Atlantic University | Gisele Galoustian
Edited by: Scientific Frontline
Reference Number: zoo071526_01