A new species of monkey has been identified in Africa, researchers have said.
The species, known locally as the lesula, was discovered after a young female was seen kept captive at the home of a primary school director in the Democratic Republic of Congo in 2007.
The young animal resembled an owl faced monkey (Cercopithecus hamlyni) but its colouring was different to that of any known species, the researchers writing in the journal PLoS ONE said.
Other wild lesula (Cercopithecus lomamiensis) have since been found in their remote range in central Democratic Republic of Congo, formerly Zaire, where they live in forests and feed on leafstalks, fruit and flower buds.
The discovery of the new species, in one of the country's last unexplored forest areas, is only the second time a new monkey species has been found in Africa in the last 28 years.
Although the 6,500 square mile area in which the shy lesula is found is remote and sparsely populated, the researchers warn the monkey is vulnerable to extinction as a result of hunting for bush meat.
They called for controls on hunting and the creation of a protected area covering its range to conserve the lesula and other wildlife found in the region.
Researcher John Hart said: "The challenge for conservation now in Congo is to intervene before losses become definitive.
"Species with small ranges like the lesula can move from vulnerable to seriously endangered over the course of just a few years."
The Congo's rainforests, smaller in size only to the Amazon, are also home to chimpanzees, mountain gorillas, bonobos, okapi and white rhinos.