Kate Detwiler said encountering a group of the newly described monkey often feels as though researchers are studying each other. That detail sits at the center of Colobus congoensis, a species with orange lips that scientists described from the forests of the Democratic Republic of Congo.
The description, published in PLOS One, makes Colobus congoensis only the fifth new species of African monkey described in the last 75 years. Researchers now say the monkey’s small known range and limited numbers could justify Endangered status on the IUCN Red List.
From blurry image to species name
The trail began in 2008, when conservationists snapped a blurry image of an unidentified primate during an expedition in the Lomami National Park area. A second sighting in 2018 pushed researchers to launch a mission to find and describe the monkey, turning a brief glimpse into a formal scientific search.
Over the next four years, researchers logged 114 sightings across 1,700km2 between the Lomami and Lilo rivers. The monkeys were usually seen in small groups of around six and often alongside other monkey species.
Orange lips, black fur, and a distinct call
Colobus congoensis has conspicuous orange lips, black fur, and a white patch around the anus. Kate Detwiler and Junior Amboko observed that the monkey has a quiet and watchful nature, does not usually flee when humans encounter it, and climbs higher into the canopy to watch observers.
The monkeys also produce loud calls known as roars that carry over long distances. Those vocalisations are acoustically distinct from those of other colobus monkeys, while morphological and genetic analyses showed that likweli are most closely related to black colobus monkeys, Colobus Satanas.
DRC forest range under pressure
Colobus congoensis and Colobus Satanas are separated by over 1,200km of forest and more than 3.5 million years of evolution. That gap helps explain why the new species stands apart even before conservation questions come into view.
Kate Detwiler said, "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." The study says the species may face pressures from hunting and habitat loss, and the researchers recommend that Colobus congoensis be classified as Endangered on the IUCN Red List.
The discovery also underscores the importance of Lomami National Park for primate conservation. For readers in the DRC forest region, the open question is how large the total population of Colobus congoensis really is, because the species has only just moved from scattered sightings to a named place in the scientific record.
