When Laura Marsh caught a glimpse earlier this year of the Vanzolini bald-faced saki monkey, with its distinctive golden limbs and “Beatles-Style” moptop, the primatologist said she immediately burst into tears.

“It was fantastic,” she told National Geographic in a recent interview. “I was trembling and so excited I could barely take a picture.”

The Vanzolini saki, named for Brazilian zoologist and composer Paulo Vanzolini, hadn’t been seen alive for some 80 years. The last time was in 1936, when an Ecuadorian naturalist named Alfonso Olalla had collected several specimens of the primate during an expedition to the remote Upper Juruá watershed in the Brazilian Amazon. A few dead specimens were later found in the 1950s, but very little was otherwise known of the elusive creature.

Marsh, an expert on saki monkeys and the director of the Global Conservation Institute, was determined to change that fact. She believed there might still be Vanzolini sakis frolicking around in the Amazon. She just needed to find them.

So, in February, she and a team including scientists, conservationists and local guides embarked on a three-month research expedition to the Upper Juruá watershed, an area that has received little scientific attention.

The expedition was the first survey of mammals in the area in over 60 years, said Christina Selby, a journalist who accompanied Marsh’s team, in a report for Mongabay. The team’s main goal, Selby said, was to find the “missing” Vanzolini saki.

[3 years ago] Scientists uncover five new species of ‘toupee’ monkeys in the Amazon: https://t.co/4m6llapy8W pic.twitter.com/k3L3RljaKy — Mongabay (@mongabay) September 4, 2017

A few days into the expedition, the team fulfilled that dream.

Selby said the team had been traveling in a metal canoe along the Eiru River, a tributary of the Juruá River, when their field guide spotted “a black monkey leaping from branch to branch in a tall tree a couple hundred feet into the forest.”

“With its thick hair and long fluffy tail, the [Vanzolini] saki monkey is easily distinguished from other monkeys that share these forests, even as a distant shadow,” wrote Selby.

Over the next three months, Marsh and her team found several other specimens of the once-“lost” Vanzolini saki at various spots along the Eiru River.

The researchers watched as the primates moved “cat-like” through the trees, walking on all fours along branches. As National Geographic explains, the Vanzolini saki does not have a prehensile tail like some other primates, meaning it has to rely on the dexterity of its limbs to explore the forest.

Rare Mop-Topped Monkey Spotted in Brazil for First Time in Over 80 Years https://t.co/b7JtLpwBFf via @gizmodo — Christina Selby (@ChristinaSelby) August 23, 2017

Thrilled as they were to find such abundant evidence of the Vanzolini saki’s existence, the research team said they also discovered some disturbing truths about the creature and its future. The saki, like many species, is facing mounting threats in its Amazonian habitat, including hunting, deforestation and other types of human activity.

Hunting, in particular, appears to be threatening not just sakis but other primates, large birds and other creatures in the Upper Juruá area.

“Given what we’ve seen, if no further controls on hunting and forest clearing are put into place outside of what limited reserves currently exist, the saki’s conservation status may become critical,” Marsh told Selby in an interview for Mongabay.

According to National Geographic, Marsh will be a making a recommendation to the International Union for Conservation of Nature regarding the Vanzolini saki’s population status, which is currently listed as unknown. Marsh said she will “likely recommend” the creature be classified as threatened.

Find out more about Marsh’s Amazonian expedition, nicknamed Houseboat Amazon, on the research team’s website. The expedition’s findings will be published in an upcoming issue of the journal Oryx.