Primate ecologist Dr Laura Marsh of the Global Conservation Institute in Santa Fe, NM, has described five new species of the genus Pithecia (saki monkeys) from Brazil, Bolivia and Peru.
The Ryland’s bold-faced saki (Pithecia rylandsi) in Zoo Parque Itaituba, female. Image credit: Arlete.
Saki monkeys, or sakis, are a poorly studied group of primates native to South America.
Found in tropical forests from the Guiana Shield, west to the foothills of the Andes in Ecuador and Peru, south to northern Bolivia, and throughout the Amazon Basin in Brazil as far east as Altamira on the Rio Xingu, these fast moving, medium-sized primates have fascinated scientists for years.
Also known as ‘flying monkeys,’ they can quickly flee an area through the treetops in a series of leaps of up to 9 meters.
They form small groups of 2 to 9 individuals, generally comprising a single male-female breeding pair and several young.
A new ten-year taxnonomic study, carried out by Dr Marsh and based upon a large number of museum specimens and photographs of live sakis, recognizes 16 distinct species: five previously established, three reinstated, three elevated from subspecies level, and five newly described species.
The descriptions of the five new species – the Ryland’s bold-faced saki (Pithecia rylandsi), the Mittermeier’s Tapajos Saki (Pithecia mittermeieri), the Isabel’s Saki (Pithecia isabela), the Cazuza’s saki (Pithecia cazuzai), and the Pissinatti’s bald-faced saki (Pithecia pissinattii) – are detailed in the journal Neotropical Primates (part 1 & part 2 of the paper in .pdf).
The Ryland’s bold-faced saki (Pithecia rylandsi):
The Ryland’s bold-faced saki (Pithecia rylandsi). Image credit: Stephen Nash / Conservation International.
The species is named after Dr Anthony Rylands, a senior research scientist at Conservation International and deputy chair of the IUCN/SSC Primate Specialist Group.
“The revised scientific description of the sakis is a major step in our understanding of primate diversity in Amazonia and worldwide,” Dr Rylands commented on the study.
The Ryland’s bold-faced saki is one of the largest of the sakis.
Illustration of what appears to be the Ryland’s bold-faced saki (Pithecia rylandsi) drawn in 1790 by Alexandre Rodrigues Ferreira as part of his explorations into the southern Brazilian Amazon.
Males and females have bare faces with black pigmentation.
When young, the males are black and moderately to heavily grizzled with white throughout. As they age, they become almost entirely white. The hands and feet are white to off-white.
The Ryland’s bold-faced saki (Pithecia rylandsi) in Pando, Bolivia, adult male. Image credit: Leila Porter.
Adult females can be as intensely white as males and the hair on the forehead, creating ‘bangs,’ can look like a white shield.
This species is found in north-western Bolivia, south-eastern Peru, and possibly in the south of the state of Rondônia and the west of the state of Mato Grosso in Brazil.
The Mittermeier’s Tapajos Saki (Pithecia mittermeieri):
The Mittermeier’s Tapajos Saki (Pithecia mittermeieri). Image credit: Stephen Nash / Conservation International.
The species is named for Dr Russell Mittermeier, President of Conservation International and long-time Chairman of the IUCN/SSC Primate Specialist Group.
“Saki monkeys, like many rain forest primates, are excellent indicators for the health of tropical forest systems,” Dr Mittermeier said.
“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.”
Illustration of a subadult or adult male Mittermeier’s Tapajos Saki (Pithecia mittermeieri) by Alexandre
Rodrigues Ferreira (1783–1792).
The Mittermeier’s Tapajos Saki is one of the most variable of all sakis.
The coat of adult males has long white bands of grizzling throughout the black, and the forearms are densely covered in shorter white hairs. The hands and feet are white. The ruff is bright orange, but varies in density and extent among individuals.
The female coat is similar to that of males, but generally much less grizzled, especially when younger.
The Mittermeier’s Tapajos Saki (Pithecia mittermeieri), juvenile male. Image credit: L.C. Marigo.
Head-body length ranges from 35 to 46 cm, the tail ranges between 41 and 49 cm.
The species is found only in Brazil, south of the Rio Amazonas between the rios Madeira and Tapajos.
The Isabel’s saki (Pithecia isabela):
The Isabel’s saki (Pithecia isabela). Image credit: Stephen Nash / Conservation International.
The species is named for an aristocratic colonial Peruvian (recte Ecuadorian) woman named Isabel Grameson Godin des Odonais.
“In 1768, after a 20-year separation from her husband Jean Godin, a cartographer on Charles Marie La Condamine’s historic expedition to measure the equator, she mounted an expedition to French Guiana to rejoin him. Her Indian porters, personal African slaves, young Quichua handmaidens, two brothers, a seven-year old nephew, and other travelers amounting to a total of 41 people struck out to cross the Amazon starting from the Río Bamba in the Andes. In less than a month, all of the members of her party either abandoned her or died leaving Isabel alone to struggle in the rainforest for 28 days,” the scientists wrote in the paper.
“She was eventually found by Quichua Indians, who nursed her to health and took her downstream to Andoas, where the priests sent her through the mission system via the ríos Marañon and Amazon. She eventually reached her husband in French Guiana, where they had a happy reunion. Isabel’s story of courage and strength is an amazing piece of South American history that absolutely needed proper recognition.”
The Isabel’s saki (Pithecia isabela), adult female. Image credit: M. Bowler.
Males of the Isabel’s saki have a black coat with very light, short white stippling. The ‘hood’ that forms in all saki monkeys with the whirl of hair at the base of the neck is black with little or no stipples. The facial ring is dark black in adult males and brown in young males. The skin of the face is black. The hands and feet are white to off-white.
The female coat is similar to that of the male in that it is black, coppery in some specimens, with short, light grizzling throughout. The facial disk is black and silky in young females.
Head-body length ranges from 77 to 92 cm, the tail is 40-49 cm long.
This species is found only in Peru.
The Cazuza’s saki (Pithecia cazuzai):
The Cazuza’s saki (Pithecia cazuzai). Image credit: Stephen Nash / Conservation International.
“The name was selected for a respected, world renowned Brazilian primatologist, Dr José ‘Cazuza’ de Sousa e Silva-Júnior who has worked many long years at the Museu Paraense Emílio Goeldi in Belém, now as the Curator of Mammals.”
The male’s coat is black with the tips dotted in white. The hands and feet are off white. The skin on the face is black.
Females have a black coat. The hands and feet are white with only very slightly brownish cuffs on the wrist.
The Cazuza’s saki (Pithecia cazuzai) in the Mamirauá Reserve for Sustainable Development, Brazil, male at left and female at right. Image credit: Felipe Ennes.
The Cazuza’s saki has a head-body length of 35 to 60 cm, with the males usually being larger than females. The length of the tail ranges from 30 to 49 cm.
The species is found in Brazil and is currently known only from very northern sections south of the Rio Solimões on either side of the Rio Juruá at Fonte Boa and Uarini.
The Pissinatti’s bald-faced saki (Pithecia pissinattii):
The Pissinatti’s bald-faced saki (Pithecia pissinattii). Image credit: Stephen Nash / Conservation International.
The species is named for Dr Alcides Pissinatti, a Brazilian veterinarian, director and co-founder of the Centro de Primatologia do Rio de Janeiro, and Vice President of the Brazilian Academy of Veterinary Sciences.
Adult males have a distinct ruff ranging from bright to dull orange. The coat of younger males is very grizzled in general, much more like that of females, and in older males is less so. Faces are mostly bare and are deep reddish.
In females, the back is tanner, especially on the arms and legs. The ruff is present with dark brown base hairs ending in lighter tan to buffy bands.
The Pissinatti’s bald-faced saki (Pithecia pissinattii), at Juma Jungle Lodge, Brazil, adult male. Image credit: Crijnfotin.
Male and female faces are mostly pinkish to a darker red, tending toward black in older females.
This species has a head-body length of 41 to 55 cm. The tail ranges between 42 and 52 cm.
It is known only from Brazil, south of the Rio Solimões in the northern area between the rios Purus and Madeira.
The study increases the number of primates in Brazil to 145; the highest diversity for any single nation.
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Laura K. Marsh. 2014. A Taxonomic Revision of the Saki Monkeys, Pithecia Desmarest, 1804. Neotropical Primates vol. 21, no. 1, pp. 1-163
