Fossil of smallest monkey species discovered

Researchers from the National Museums of Kenya, University of Arkansas, University of Missouri and Duke University have announced the discovery of a tiny monkey that lived in Kenya 4.2 million years ago.

“Nanopithecus Browni” was the same size as a modern talapoin monkey, the smallest living Old World monkey species that weighs in at only 2 to 3 pounds, about the size of a cottontail rabbit.

Talapoins are part of a large group of monkeys called guenons, which are commonplace in Africa today. Most species are bigger than Nanopithecus.

Guenon evolution is poorly understood, but thought to be driven by changes in forest habitats, with the distribution of modern species reflecting the breakup and re-convergence of ancient forests.

Talapoins which are found in West and Central Africa, are confined to tropical forests, and are thought to be dwarfed from a larger ancestor in response to life in woody, swampy habitats.

Nanopithecus, though, was found in Kenya on the eastern side of the continent, at a site called Kanapoi.

The Kanapoi habitat was dry, and covered with grasslands and open forests – a very different place from the tropical forests of Cameroon and Gabon.

It is also at Kanapoi where remains of some of the earliest human ancestors, Australopithecus Anamensis have been found, who would have lived alongside Nanopithecus. 

Nanopithecus is the second oldest guenon found so far, just younger than a single tooth from the Arabian Peninsula.

The ancient date, combined with a habitat so different and so far away from that of modern talapoins, reveals a much more complex evolution of guenon monkeys than previously thought.

This new enigmatic member of the primate family reveals that dwarfing occurred far longer ago than scientists suspected.