New Species Of Monkey Discovered In The Amazon Rainforest


Mico argentatus - a different but related species of marmoset to the newly discovered mico munduruku. One big difference is the color of the tail. Tarcisio Schnaider/Shutterstock

Ecologists have spotted an entirely new species of marmoset living in remote areas of the Amazon.

Mico munduruku stands apart from other Amazonian marmosets with its uniquely snowy tail. Typically, they are black. The discovery appeared in PeerJ – an open-access peer-reviewed scientific journal – last week.


The bulk of museum specimens of Amazonian marmosets were gathered by naturalists and professional collectors in the 18th and 19th centuries, which tends to mean that specimens available to study have been sourced from a select few locations, while biological samples are all but absent from tissue collections, the article authors say.

It also means that it is not altogether unlikely that there is another species or subspecies of marmoset living in the Amazon – as we see here.

An illustration of the Mico munduruku. Credit: Stephen Nash

Rodrigo Costa-Araújo from the National Institute of Amazonian Research in Brazil first stumbled upon the new species by accident. A band of three monkeys were sitting in the treetops in an area of the south-eastern Amazon close to the Tapajós and Jamanxim rivers when Costa-Araújo noticed their unusual pigmentation. 

To find out more, Costa-Araújo and his team organized 10 expeditions between 2015 and 2018 to "key" areas of the southern Amazon with little to no information on marmosets, jotting down the geographic coordinates as well as the time and habitat type of each white-tailed marmoset sighting. The researchers also collected five specimens for a closer examination under a permit issued by the Chico Mendes Institute for Biodiversity Conservation, a division of the Brazilian Ministry of the Environment.


The marmosets' markings and pigmentation were the first characteristics distinguishing them from others in their genus. Aside from having a white tail, the individuals displayed a beige-yellowish back, white hands, white feet, and white forearms with a beige-yellowish patch on their elbow.

Their DNA was the second. Costa-Araújo and his team explain their genomes show they are closely related but separate from other known Amazonian marmosets.

The marmoset sightings suggest Mico munduruku ("mico" – Latin for "flash" – is a genus containing certain marmosets; "munduruku" are indigenous people living in the Amazon River basin) can be found in a 55,000-square-kilometer (21-square-mile) region covering seven localities. Unfortunately, this is an area facing extensive environmental degradation as a product of illegal logging and agricultural expansion. Plans to build four new hydroelectric plants pose another threat to the only recently discovered animal. 

"Thus, just as we have discovered this species, we already need to be concerned about its survival," the article authors write.


The "threats will only increase as hydroelectric plants and complementary infrastructure schemes such as roads and transmission lines come to completion, inducing more intense settlement and forest reduction in the region."

The study authors say more research is "urgently needed" so as to be able to identify the species' range, population size, and population density, and thus, figure out Mico munduruku's conservation status as well as ways to mitigate environmental threats.