"This is exciting news because it shows that the 'age of discovery' is by no means over," says William Stanley, a co-author of the study and mammal Collection Manager at The Field Museum, where the world's only specimen of this forest-dwelling monkey "resides" in the museum's vast collections.
"Finding a new genus of the best-studied group of living mammals is a sobering reminder of how much we have to learn about our planet's biodiversity," notes Link Olson, another co-author and Mammals Curator at the University of Alaska Museum.
The new African monkey, Rungwecebus kipunji (rhung-way-CEE-bus key-POON-gee), was first described scientifically last year based only on photographs. At that time, scientists placed the reclusive monkey in the genus Lophocebus, commonly known as mangabeys.
Shortly thereafter, one of these monkeys died in a farmer's trap. As a result, a team of scientists, organized by Tim Davenport of the Wildlife Conservation Society, was able to study the specimen's physical characteristics and analyze tissue samples on a molecular level. Their research has concluded that Kipunji (its common name) belongs to an entirely new genus.
Kipunji have light-to-medium grayish brown fur, with off-white fur on the belly and the end of their long, mainly curled-up tail. They have a "crown" made up of a very broad crest of long, erect hair. Adults make a distinctive, loud, low-pitched honk-bark. An omnivore, Kipunji eat leaves, shoots, flowers, bark, fruit, lichen, moss and invertebrates.
These predominantly arboreal monkeys are endemic to Tanzania and known to live in only two high-altitude locations: the Rungwe-Livingstone forest (16 groups) and Ndundulu Forest Reserve (three groups). They live in social groups of 30-36 adul t males and females, with no evidence of any solitary animals.
The research behind the new findings was remarkably collaborative, drawing on the expertise of a team of scientists spread around the world. Davenport, the lead author, Daniela De Luca, Noah Mpunga and Sophy Machaga, also co-authors, work for the Wildlife Conservation Society and are founders of the Southern Highlands Conservation Programme based in Tanzania. Another co-author, Eric Sargis, is a primatologist in the Anthropology department at Yale University, while co-author Link Olson is the Mammals Curator at the University of Alaska Museum.
"This study is a textbook example of how a variety of individuals and institutions spanning the globe can work together to significantly improve our understanding of the biodiversity of this planet," Stanley says. "Within hours of Sophy Machaga creeping through the rain-soaked forests of Rungwe documenting the behavior of a troop of Kipunji, Link Olson of University of Alaska Museum was trudging through the snow in 20-degrees-below-zero weather to his molecular lab in Fairbanks, more than 8,500 miles away."
The molecular data recovered from muscle tissue and analyzed in detail by Olson shows Kipunji is most closely related to baboons in the genus Papio, and not to Lophocebus, the genus to which Kipunji was originally assigned. The in-depth analysis involved five different genes, including genes passed only from mother to offspring and from father to male offspring. "Had we gotten these surprising results based on a single gene, we'd have been pretty skeptical," Olson says, "but each of the genes we analyzed either firmly supported the grouping of Kipunji with baboons or failed to support a close relationship between Kipunji and other mangabeys."
Meanwhile, Sargis flew to Chicago with only a week's notice to work with Stanley on the skull of the only specimen of Kipunji. They used the Field Mus eum's extensive primate collection to compare Kipunji with other primates and found that the skull and external features of the specimen do not exhibit the diagnostic morphological features of baboons: namely, a long rostrum or deep depressions on the outside of the lower jaw. Also, depressions under the orbits of the Kipunji skull are much different than those of baboons, mandrills, and geladas.
Given the results of the molecular and morphological analyses, the team placed Kipunji in its own genus Rungwecebus, named after Mt. Rungwe where Kipunji was first observed.
Unfortunately, the forest home of this new monkey is fragmented and vulnerable. Logging, charcoal making, poaching and unmanaged resource extraction are common. Without intervention, both forests will be further fragmented, the authors note in their paper. The main predators of Kipunji are crowned eagles and possibly leopards. But humans also hunt and kill Kipunji, and eat their meat.
"Any hunting of the Kipunji or loss of its vulnerable habitat, with the latter probably increasing the frequency of the former, will further serve to threaten this important new genus," the authors conclude.