A new species of monkey with orange lips and distinctive vocalizations, which include roars and snorts, was recently identified in a remote region of the Democratic Republic of Congo (DRC). The discovery of this primate represents a significant milestone, being only the fifth new species of monkey to be found in Africa in the last 75 years, as detailed in a study published on July 15.
The scientists responsible for the study indicate that the existence of more unknown species in the area is likely. Named Colobus congoensis in honor of the region, the species is known locally as “likweli” in the Kilanga language, a common name among communities.
“It’s really remarkable because it’s not common these days to discover a new species of primate that has never been documented, especially one of considerable size,” said Joshua Linder. Linder is an anthropologist and president and co-founder of The Forest Collective, a nonprofit organization dedicated to the conservation and restoration of tropical forests.
The story of the discovery began in 2008, when environmentalists in Lomami National Park, located in the Congo Basin, Democratic Republic of the Congo, photographed an unidentified, although partially obscured, monkey. A decade later, in 2018, an animal with similar characteristics was recorded on video. This new record motivated Junior Amboko, co-author of the study, researcher at Lomami National Park and anthropologist at Florida Atlantic University, to begin an expedition in search of the enigmatic primate.
With the aim of validating existing information, Amboko and his team presented the images to residents of 52 villages in the area surrounding the park.
“These communities have in-depth knowledge of the local fauna and flora,” explained Amboko. He added that, in only eight of the villages visited, the monkey was known to some hunters, who, although aware of the economic and nutritional value of the animals, had little additional information about the species.
Among hunters of the Balanga ethnic group, the monkey was called “likweli”, the meaning of which remains uncertain. On the other hand, in Mituku communities, the species was known as “kasaba nkoni”, a term that, according to Amboko, translates as “one who shakes the branches”. This name alludes to the agile way in which Colobus monkeys move between trees.
During expeditions carried out from 2018 to 2022, scientists documented 114 sightings of the primate in an area of approximately 1,700 square kilometers. This region, naturally isolated by the Lomami and Lualaba rivers, was the stage for the discoveries that were published on July 15 in the journal PLOS One.
Observed in groups ranging from one to twenty individuals, these monkeys have a shiny black coat as their main characteristic. However, what catches the most attention is a prominent orange patch around the mouth and nose. The gray skin on their cheekbones suggests the image of a mask, and they also sport a patch of white hair near the anus.
“The face and the rump region are the two features that we consider most distinct,” explained Kate Detwiler, anthropologist and study co-author from Florida Atlantic University. She detailed: “When observing the face, you can see bare skin with a unique cream-orange tone. And on the back, a white spot stands out.”
Weighing approximately 7 kilos, the monkeys also produce deep, sonorous roars, complemented by peculiar grunts. These vocalizations, according to Detwiler, are a distinctive trait that sets them apart from other Colobus monkeys.
The team confirmed that Colobus congoensis was a new species by collecting and sequencing DNA from monkeys that had been killed by hunters and destined for illegal trade. The results were compared with genetic data, skulls, teeth and skins from other Colobus monkeys present in museum collections and databases.
Despite sharing the same forest habitat with the Angolan colobus (Colobus angolensis), the closest relatives of Colobus congoensis are the black colobus monkeys (Colobus satanas). The latter reside approximately 1,200 kilometers to the west, in countries such as Cameroon, Gabon and Bioko Island.
“It is notable that the results point to the black colobus as the closest living relative of this new species, even though it is located 1,200 km away in West Africa,” commented Linder, who was not directly involved in the new study.
Detwiler calculated that the divergence between these close relatives occurred between 5.78 million and 3.44 million years ago, representing the largest known separation between species within the genus Colobus. “This discovery is transforming the way we understand the evolution of African apes,” he said.
Considering its limited geographic distribution, the rarity of sightings and the ongoing loss of habitat, the researchers suggest that Colobus congoensis be classified as an endangered species on the IUCN (International Union for Conservation of Nature) Red List.
The new discovery reinforces the relevance of Lomami National Park, where, in 2012, a team that included Detwiler also documented another previously undescribed monkey, the lesula (Cercopithecus lomamiensis).
The Congolese rainforest, which covers this portion of Africa, ranks second in global size, right after the Amazon, with approximately 60% of its extension in the Democratic Republic of Congo. Amboko described it as “a paradise for biodiversity”, highlighting the possibility that there are even more uncatalogued primate species. “If we were able to discover two new species of primates, it is difficult to imagine how many other species of mammals, fish, reptiles or plants could still be hiding there,” he concluded.
