The monkey, known by people in the Democratic Republic of Congo as the lesula, has a blond chin and upper chest, in contrast to its dark limbs. It has a reddish-colored lower back and tail.
“And adult males have a huge bare patch of skin in the buttocks, testicles and perianal area,” said John A. Hart, the researcher who described the coloring. “It’s a brilliant blue, really pretty spectacular.”Dr. Hart is a field scientist with the Lukuru Foundation, a wildlife research group; his colleagues include his wife, Terese Hart. They report their findings in the journal PLoS One.
The researchers found that the monkeys live in the central part of the Democratic Republic of Congo and have a range of about 6,500 square miles.
The first lesula seen by researchers was a captive one, the pet of a schoolgirl. Although it bore a strong resemblance to another species, the owl-faced monkey, the unusual coloring made the researchers suspect it was something new.
They were able to identify more lesulas in the wild and locate hunters with specimens of the monkey. They analyzed tissue samples to confirm that the lesula is in fact genetically distinct from other species.
The lesula lives in remote regions that are largely unthreatened by human settlement. But John Hart warned, “Under the current trends of uncontrolled bush-meat hunting, it could become very endangered.”
This article has been revised to reflect the following correction:
Correction: September 14, 2012
An earlier version of this article erroneously included a photograph of a monkey species that is distinct from the newly discovered Cercopithecus lomaniensis, known as the lesula, and the caption described both images incorrectly. The photograph showed a dark-colored male of the species Cercopithecus hamlyni, known as the owl-faced monkey; it did not show a male lesula. The lighter-colored lesula in the photograph that remains is a male, not a female.
