The aptly named monk saki monkey in Colombia (Pithecia monachus). A new review uncovers five new species in this largely-mysterious primate group. Photo by: Rhett A. Butler.
While saki monkeys may be characterized by floppy mops of hair that resemble the worst of human toupees, these acrobatic, tree-dwelling primates are essential for dispersing seeds across the vast Amazon landscape as they primarily dine on fruit. After long being neglected by both scientists and conservationists, a massive research effort by one intrepid researcher has revealed the full-scale of saki monkey diversity, uncovering five new species.
Laura Marsh, the director and co-founder of the Global Conservation Institute, spent ten years studying the saki monkey family, which make-up the genus Pithecia.
“I began to suspect there might be more species of saki monkeys when I was doing field research in Ecuador,” Marsh said who published her findings in Neotropical Primates, which is published by the IUCN’s Species Survival Commission’s Primate Specialist Group and Conservation International (CI).
 One of the five new species uncovered by Laura Marsh: a juvenile male Mittermeier’s Tapajós saki. Photo by: © Conservation International/photo by Russell A. Mittermeier. |
“The more I saw, the more I realized that scientists had been confused in their evaluation of the diversity of sakis for over two centuries.”
During the 18th and 19th centuries, scientists discovered seven saki monkey species; four more were named in the twentieth century, for a total of 11 species. But Marsh’s study, which runs to over 160 pages, increases the family’s diversity by 45 percent for a grand total of 16 proposed species.
Previously, the five new species were either considered subspecies or merely variants of already-described sakis. While saki monkeys are found across the whole Amazon rainforest, the five new species are confined to Brazil, Peru, and Bolivia. In fact, three of the new species are only found in Brazil, which makes the country the record holder in primate diversity with known 145 species.
Unlike many new studies in taxonomic research, Marsh did not do genetic research, but instead depended on museum specimens, photos, and live animals to determine the new species. The new species are Cazuza’s saki, (Pithecia cazuzai), Isabel’s saki (Pithecia isabela ), Mittermeier’s Tapajós saki (Pithecia mittermeieri), all found in Brazil; Pissinatti’s bald-faced saki (Pithecia pissinattii) from Peru; and Rylands’ bald-faced saki, (Pithecia rylandsi) in Brazil, Peru, and Bolivia.
“Saki monkeys, like many rain forest primates, are excellent indicators for the health of tropical forest systems,” said Russell Mittermeier, primatologist and President of CI. “This revision of the genus shows clearly how little we still know about the diversity of the natural world that surrounds us and upon which we ourselves depend so much.”
Mittermeier was honored by one of the new species being named after him: Mittermeier’s Tapajós saki
Compared to many of the world’s primates, saki monkeys have been little studied making it difficult to know if any of the species are threatened with extinction.
“A great deal of research needs to be done on existing populations, the limits of their distributions, and the human impacts they face before we can confidently report on their status,” Marsh writes in her paper.
Yet, as a family, saki monkeys face a variety of threats.
 Humans aren’t the only species that have bad hair days. A captive female golden-faced saki. Photo by: © Conservation International/photo by Russell A. Mittermeier. |
“[Saki monkeys], like all South American primates, suffer from the effects of region-wide habitat disturbances, including
fragmentation of their habitats and hunting. Sakis are hunted throughout their range for subsistence, pets, trophies (e.g., as a
tourist trade commodity in Ecuador as ‘shrunken heads,’), and their tails used as ‘feather dusters’ or their skins for hats,” Marsh writes.
Yet she hopes that her new study will help push for new conservation efforts.
“Ultimately, the goal is to conserve as many saki species in the wild as possible, and that is only achievable with a working taxonomy. My rationale for this work was to ‘tame the madness’ of [saki] taxonomy, not to perfectly corroborate every specimen or living saki out there,” she adds.
The saki family is not the only primate groups that’s being re-written.
“In the 1980s, people believed that there were about 180 species of primates worldwide. Thanks to the dedication and skill of researchers such as Laura Marsh, today we have a clearer understanding of the diversity of the mammalian Order that gave rise to our own—496 species, and counting,” said Anthony Rylands, a Senior Researcher with CI and Deputy-Chair of the Primate Specialist Group, who also got a new saki named after him: Rylands’ bald-faced saki.
The world’s saki monkeys in order of discovery, according to new paper:
- White-faced saki (Pithecia pithecia), 1766
- Monk saki (Pithecia monachus), 1812
- Burnished saki (Pithecia inusta), 1823
- Hairy saki (Pithecia hirsuta), 1823
- Rio Tapajós saki or Gray’s bald-faced saki, (Pithecia irrorata), 1842
- Golden-faced saki, (Pithecia chrysocephala), 1850
- White-footed saki or Buffy saki, (Pithecia albicans), 1860
- Miller’s saki, (Pithecia milleri), 1914
- Napo saki, (Pithecia napensis), 1938
- Equatorial saki, (Pithecia aequatorialis), 1987
- Vanzolini’s bald-faced saki, (Pithecia vanzolinii), 1987
- Cazuza’s saki, (Pithecia cazuzai), 2014
- Isabel’s saki, (Pithecia isabela ), 2014
- Mittermeier’s Tapajós saki, (Pithecia mittermeieri), 2014
- Pissinatti’s bald-faced saki, (Pithecia pissinattii), 2014
- Rylands’ bald-faced saki, (Pithecia rylandsi), 2014
A male buffy saki (Pithecia albicans) on the Rio Tefe, Amazonas, Brazil. Studying saki monkeys is further complicated by variations in males and females of each species. Photo by: © Conservation International/photo by Russell A. Mittermeier.
Male white-faced saki in captivity. Photo by: © Conservation International/photo by Russell A. Mittermeier.
Citations:
- Marsh, Laura. (2014) A Taxonomic Revision of the Saki Monkeys, Pithecia
Desmarest, 1804. Neotropical Primates 21(1).
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