The 2-pound (0.9-kilogram) creature didn't make itself easy to find. The orange-brown mammal lives out a solitary existence in the dense, hard-to-study cloud forests of Colombia and Ecuador, which inspired part of its Latin name Bassaricyon neblina: Neblina is Spanish for "fog."
What's more, the large-eyed critter is active only at night, when it hunts for fruit in its Andean habitat.
Helgen got his first hint of the olinguito’s existence when he was studying olingo skins in Chicago's Field Museum in 2003 and found odd specimens that looked nothing like other olingos.
This sparked a ten-year search to find the mystery animal, later named the olinguito, which was formally announced as its own species on August 15 in the journal ZooKeys.
Photograph by Paul Souders, Corbis
The kinkajou (pictured above in Costa Rica) is another tree-dwelling, nocturnal member of the raccoon family and a relative of the olinguito.
The animal is plentiful in the same cloud forests as the olinguito. Helgen and colleagues saw a kinkajou on the same night in 2006 that they first spotted the olinguito, in western Ecuador's Otanga Cloud Forest Preserve. (Watch a kinkajou video.)
Photograph by Norbert Wu, Minden Pictures/Corbis
Olinguitos should survive for the foreseeable future: "Hearteningly, it's not an extremely endangered species," Helgen said.
But that doesn't mean there aren't any threats: An estimated 42 percent of the olinguito's habitat has already been converted to agriculture or human settlements, according to the researchers, and deforestation is a continuing concern.
Photograph courtesy Mark Gurney
Fuzzy Forest Dweller
The olinguitos' reddish, fuzzy coats allow them to live at chilly elevations between 5,000 and 9,000 feet (about 1,500 to 2,700 meters).
Like some other carnivores, such as the giant panda, olinguitos seem to eat mostly plants, but are nevertheless part of the taxonomic order Carnivora.
"The age of discovery is not over," Helgen said. "In 2013 we have found this spectacular, beautiful animal, and there's a lot more to come."