Orange Lips And No Thumb: Strange New Monkey Species Discovered In Congo Rainforest

Scientists have formally described a striking new species of monkey from the rainforests of the Democratic Republic of Congo, marking only the fifth new African monkey species identified in the past 75 years. The primate, named Colobus congoensis and known locally as Likweli , was discovered in the Lomami National Park , a remote stretch of forest between the Lomami and Congo rivers in east central DRC.

The study, published this week in the journal PLOS One , was led by Kate Detwiler of Florida Atlantic University along with Junior Amboko of the Lukuru Wildlife Research Foundation . Researchers say the monkey is small, weighing around seven kilograms, and is instantly recognisable for its striking orange cream patch around the mouth, nose and philtrum set against an otherwise black face, along with a white perianal patch. It lacks a thumb entirely, a trait shared by other African colobine monkeys.

The mystery began in 2008 when a blurred photograph hinted at an unknown primate. A clearer image a decade later, followed in 2020 by a dedicated study called the Likweli Project , advanced the investigation, but it was tissue samples recovered from specimens confiscated from hunters in 2021 that finally allowed conclusive genetic testing. Analysis showed the species diverged from its closest relative, the black colobus or Colobus satanas , between 4.3 million and 5.8 million years ago, despite the two now living over 1,200 kilometres apart.

Field surveys between 2018 and 2022 recorded only 114 sightings across a range of about 1,700 square kilometres, typically in small groups averaging six individuals, often alongside two other colobine species. Detwiler described the finding as reshaping understanding of African monkey evolution, while also calling it a sobering reminder that rare species may vanish before they are even documented. Locals describe the animal as shy and watchful, often climbing higher into the canopy to observe researchers rather than fleeing, and its call has been compared to a deep, froglike roar.

Citing its narrow range, small population and rising threats from hunting and habitat loss, researchers have proposed that Colobus congoensis be classified as Endangered on the IUCN Red List , underscoring the urgency of protecting the Congo Basin's still undocumented biodiversity.