Five new species of the notoriously elusive saki, or “flying,” monkey have been formally described in a comprehensive new study.
These swift, shy primates can be found gracefully leaping through the tropical forests of northern and central South America. It is thanks to their secretive nature that these monkeys have evaded scientists’ radars for so many years, meaning that they have remained a poorly studied group of animals.
Saki monkeys are New World monkeys belonging to the genus Pithecia. They’re small primates, weighing in at around 1.5-4.0 kg as an adult, and have long tails that often exceed their body length. Sakis can be easily recognized by their long, fluffy coats that they puff out when approached, making them appear larger and more threatening. Some species have colorful facial hair, whereas others have naked faces that are neatly hooded with fur.
Despite over 200 years of study into the taxonomy of sakis, there has been considerable confusion over some species. Furthermore, few long-term field studies of these primates exist. In order to fill in knowledge gaps, behavioral ecologist Laura Marsh painstakingly examined 876 saki skins and 690 skulls from museum specimens that were spread across 17 different countries. She also scoured hundreds of high-resolution photographs of both captive and wild sakis.
Organizing the saki family tree was no mean feat. Many species were found to be remarkably diverse, making it difficult to assign specimens to a particular species. Furthermore, some females have large, protruding clitorises that were often misconstrued as a penis. Field studies were also particularly tricky since the stealthy sakis have a habit of toning down their vocalizations when researchers approach them.
Despite the setbacks, Marsh produced a comprehensive revision of these primates, which has been published in the journal Neotropical Primates. She found that there are 16 known species of Pithecia, five of which are newly identified. The previously undescribed species are the Cazuza’s saki, Mittermeier’s Tapajós saki, Rylands’ bald-faced saki, Pissinatti’s bald-faced saki and Isabel’s saki.
“This revision of the genus shows clearly how little we still know about the diversity of the natural world that surrounds us and upon we ourselves depend on so much,” said Russell Mittermeier, president of Conservation International. One of the species, P. mittermeieri, was named after Mittermeier, and the others were named after prominent primatologists and conservationists.
While we still know little about saki behavior and status, studies such as this are critical for conservation efforts. “If we can’t name it, we can’t save it,” Marsh told National Geographic. “If we’re calling everyone one species and it’s really ten different things, you have just lost part of the biodiversity on Earth.” Future studies will therefore aim to gather information on species abundance and also investigate their vulnerability.