Thursday, July 16, 2026

CUNY Graduate Center research helps confirm discovery of new African monkey species

Anthropology Professor Christopher Gilbert and collaborators identify one of the first new African monkey species described in more than 75 years

The Graduate Center, CUNY

S1_video_congoensis — video:
Colobus congoensis, known locally as “likweli,” has deep resonant roaring calls that resemble those of related Colobus species but possesses a distinct acoustic structure.
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Credit: Bernard Bonanga

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

Striking new species of African monkey discovered deep in the Congo rainforest

Florida Atlantic University

C. Congoensis — image:
A photograph of Colobus congoensis, whose common name is the local vernacular name, “likweli.”
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Credit: Daniel Rosengren

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 the last 75 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 4 to 5 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, as well as Lomami National Park, 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 – about 15 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 4 to 5 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 a very large 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 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.

“In order 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 pretty 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 dependent on scattered upland forest patches in the Congo Basin.

But 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.

Study co-authors are Emma R. Horton and Kathryn F. Coates, FAU’s Department of Biological Sciences; Jean-Pierre Kapale, Lukuru Wildlife Research Foundation and Lomami National Park, Frankfurt Zoological Society; Mardoché B. Koko, Lomami National Park, Frankfurt Zoological Society; Terese B. Hart, Ph.D., Lukuru Wildlife Research Foundation; and Eric J. Sargis, Ph.D., Yale University, Yale Peabody Museum, and Yale Institute for Biospheric Studies.

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Journal

PLOS One

Method of Research

Observational study

Subject of Research

Animals

Article Title

Likweli: A remarkable new species of Colobus monkey from the Lomami National Park, Democratic Republic of Congo

Article Publication Date

15-Jul-2026

C. Congoensis [VIDEO] |

Colobus congoensis, known locally as “likweli,” has deep resonant roaring calls that resemble those of related Colobus species but possesses a distinct acoustic structure.

Vocalizations [AUDIO] |

Credit

Bernard Bonanga

Colobus congoensis map

Credit

John Hart, Lukuru Wildlife Research Foundation

Colobus congoensis and C. satanas in life. (A & B) C. congoensis, Lomami National Park, Democratic Republic of Congo.

Credit

(A) Daniel Rosengren, (B) Bravo Bofenda. (C & D) C. satanas, Lope National Park, Gabon. Photo credits: (C) Martin Royele/Royele Safaris, (D) Barna Takats. Photos used with permission.

Junior Amboko (left) and Mardoché B. Koko working in the field in the Lomami National Park.

Colobus congensis, known locally as “likweli,” has a dramatic black face with pinkish-orange lips.

Credit

Junior Amboko, Florida Atlantic University

New species of monkey with unusual orange lips discovered in the Democratic Republic of Congo

The rare, endangered monkey, ‘Likweli’, can be identified by its facial markings and unique call

PLOS

Likweli: A remarkable new species of Colobus monkey from the Lomami National Park, Democratic Republic of Congo — audio:
*Colobus congoensis*, known locally as “likweli,” has deep resonant roaring calls that resemble those of related Colobus species but possesses a distinct acoustic structure.
view more
Credit: Mardoché B. Koko, CC-BY 4.0 (https://creativecommons.org/licenses/by/4.0/)

Scientists have described a new species of colobus monkey in the forests of the Democratic Republic of Congo (DRC), report John Hart at Lukuru Wildlife Research Foundation and colleagues on July, 2026 in the open access journal PLOS One.

The first hint that a new primate species might be hiding in the dense forests of Lomami National Park came in 2008, when conservationists photographed an unidentified monkey during an expedition. After a second sighting in 2018, researchers embarked on a dedicated mission to find and describe the mysterious monkey.

The new species, which has been given the scientific name Colobus congoensis and the common name ‘Likweli’ (the name used by local communities), has physical and behavioral characteristics that set it apart from other colobus species. Although mainly black in color, Likweli have a conspicuous orange patch around the mouth and bare grey skin on their cheek bones contrasting with black skin around the eyes, resembling a mask. They also have a distinctive patch of white fur around the anus. Likweli produce loud vocalizations called ‘roars’, punctuated by distinctive snorts. Their orange lips make these roars visually, as well as audibly, striking.

Field surveys revealed that the species occupies at least 1700 square kilometers of closed-canopy forest between the Lomami and Lilo rivers in the DRC. Their range size is believed to be a fraction of that of most other colobus monkeys, suggesting that Likweli may be very sensitive to habitat quality. The species was usually observed in small groups, often alongside other monkey species. Given their small geographic range and population size, the researchers recommend classifying the species as Endangered on the IUCN Red List.

Morphological and genetic analysis showed that Likweli are most closely related to black colobus monkeys (Colobus satanas), even though the two species are separated by over 1200 kilometers of forest. The researchers estimate that they diverged between 5.78 and 3.44 million years ago, representing a much earlier split than other species in the genus.

Colobus congoensis is only the fifth new species of African monkey to be described in the last 75 years. The discovery highlights the importance of DRC’s Lomami National Park for primate conservation. However, the species’ already restricted habitat could come under threat as human populations expand in the coming decades, so its protection is a top conservation priority, the authors say.

Junior Amboko, co-corresponding author, Ph.D. student in the Department of Biological Sciences at Florida Atlantic University, National Geographic Explorer, and Lomami National Park researcher, adds: “I was fortunate to be part of this discovery from the very beginning – from recognizing in the first photographs that we were looking at something new in the forest, to training field teams to document its behavior, analyzing the data and helping write the scientific paper. Being involved through every stage, from fieldwork to the lab, made this an especially rewarding experience. It makes it even more meaningful that the name I proposed, Colobus congoensis, was chosen. The name honors the Democratic Republic of Congo, a country with extraordinary biodiversity, and reflects the incredible natural heritage that continues to reveal new discoveries. I hope it also draws greater attention to the importance of conserving these forests and the unique species that call them home.”

Kate Detwiler, Ph.D., senior and corresponding author and an associate professor of biological sciences at Florida Atlantic University, adds: “What makes Colobus congoensis such an important discovery is that the evidence for it being a distinct species came from several independent sources. Field observations first suggested that these monkeys were unusual, detailed anatomical comparisons showed they differed from other known colobus monkeys, and genetic analyses revealed that they have been evolving separately from their closest relatives for roughly 4 to 5 million years. When those lines of evidence all pointed to the same conclusion, it became clear that we were looking at a previously undescribed primate species. Discovering a new monkey species is extraordinarily rare, and it highlights how much remains to be documented in the Congo Basin and how urgent it is to protect the small area where this species is found.”

John A. Hart, first author and a conservation scientist with the Lukuru Wildlife Research Foundation, adds: “We continue to be reminded that the Congo Basin remains one of the world’s last great frontiers for mammal discovery. 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.”

An illustration of Colobus congensis, whose common name is the local vernacular name, "likweli".

Credit

Kimio Honda, CC-BY 4.0 (https://creativecommons.org/licenses/by/4.0/)

Author interview: https://plos.io/4f5k7IC

In your coverage, please use this URL to provide access to the freely available article in PLOS One: https://plos.io/4wvCq0I

Citation: Hart JA, Amboko JD, Arenson JL, Horton ER, Coates KF, Kapale J-PI, et al. (2026) Likweli: A remarkable new species of Colobus monkey from the Lomami National Park, Democratic Republic of Congo. PLoS One 21(7): e0349857. https://doi.org/10.1371/journal.pone.0349857

Author countries: USA, Democratic Republic of Congo.

Funding: Funding for the field study of Likweli in the Lomami National Park was provided by the National Geographic Society (NGS-74097C-20), US Fish and Wildlife Service, Frankfurt Zoological Society, The Lukuru Wildlife Research Foundation, Wildcat Foundation, and Arcus Foundation. Funding from Full Circle Foundation and Rainforest Trust supported surveys in the buffer zone. Funding to support the morphological analysis was generously provided by the Yale Peabody Museum W. R. Coe Fund, Yale Institute for Biospheric Studies, the American Association of Physical Anthropologists Professional Development Program, the PSC-CUNY Faculty Award Program, the Hunter College Presidential Travel Award Program, the National Science Foundation (SBE 40F79-02 04 and SBE 2018093), the Leakey Foundation, and the Graduate Center, CUNY. Funding for the molecular analysis was provided by the Primatology Lab, FAU Foundation, Inc. at Florida Atlantic University. There was no additional external funding received for this study.