The Platyrrhini, also known as New World monkeys, are a diverse group of primates found in Central and South America. This group contains several familiar species like squirrel monkeys, capuchins, and spider monkeys. There are currently over 150 recognized species in the Platyrrhini group, making them a highly varied and successful primate radiation. In this article, we will provide an overview of the different families and genera within the Platyrrhini, discussing some of the key characteristics of the most prominent species. Understanding the diversity within this primate group provides insight into their evolution and ecology in the unique environments of the New World.
Overview of the Platyrrhini
The Platyrrhini are one of the three major groups of simian primates, along with the Catarrhini (Old World monkeys and apes) and the Strepsirrhini (lemurs and lorises). Molecular evidence indicates that Platyrrhini diverged from other anthropoid primates around 40 million years ago, likely in Africa, before migrating to South America. This migration was possible due to the connection between North and South America that existed at the time. Once in South America, the Platyrrhini diversified into the many species we see today.
Some key features that distinguish Platyrrhini from other simian primates include:
- Nostrils that are widely spaced and open sideways rather than downward
- A prehensile tail in many species
- Three premolar teeth instead of two
- The Complete absence of an enamel layer on their teeth
Within the Platyrrhini group, there are currently five recognized families:
- Cebidae – capuchins, squirrel monkeys, and more
- Aotidae – night or owl monkeys
- Pitheciidae – titis, sakis, and uakaris
- Atelidae – howler, spider, woolly, and woolly spider monkeys
- Callitrichidae – marmosets and tamarins
In the sections below, we will provide more details on the species diversity within each Platyrrhini family, including their geographic ranges, diets, and conservation statuses.
The Cebidae Family
The Cebidae family represents about half of the known Platyrrhini diversity, with over 70 species classified into 12 genera. They are found throughout much of Central and South America. Cebids vary considerably in size, ranging from the pygmy marmoset at around 10 inches tall and 4 ounces in weight, to the white-faced saki monkey measuring 25 inches tall and weighing 9 pounds. Most species have non-prehensile tails.
Some prominent Cebidae genera include:
- Capuchin monkeys – The capuchin genus contains several species including the familiar tufted capuchin and white-headed capuchin. They are omnivorous, eating fruit, insects, small vertebrates and more. Capuchins are known for their intelligence and dexterous manipulation of objects.
- Squirrel monkeys – These small, agile monkeys inhabit tropical forests and get their name from their squirrel-like appearance and actions. There are 5 main species.
- Tamarins – The 13 tamarin species are diminutive monkeys distinguished by long tails, claws for grip, and whiskered faces. They form cooperative family groups.
- Sakis – These tropical forest monkeys are adapted for life in the canopy. Some have unique facial hair patterns. They feed on ripe fruits, leaves, flowers, and insects.
- Uakaris – Found in flooded forests of the Amazon, uakaris have a distinctive facial appearance with almost no fur and bright red faces. They live in large social groups.
Many Cebidae species are threatened by habitat loss and hunting. Several tamarin species, such as the cotton-top tamarin, are endangered.
Examples of Cebidae Species
| Common Name | Scientific Name | Range |
|---|---|---|
| Tufted capuchin | Sapajus apella | Forests of much of Central and northern South America |
| Squirrel monkey | Saimiri sciureus | Central and South America |
| Golden-bellied capuchin | Sapajus xanthosternos | Southeastern Brazil, Paraguay, far northeast Argentina |
The Aotidae Family
The Aotidae family consists of just 11 species of nocturnal monkeys known as night or owl monkeys. They are found throughout much of Central and South America in tropical forests. They are relatively small monkeys with large brown eyes adapted for night vision.
Some key features of night monkeys:
- Nocturnal habits
- Monogamous social groups
- Long tails that are not prehensile
- Males and females closely bonded and share infant care duties
The diet of night monkeys consists mainly of fruits, flowers, leaves, insects, spiders, and tree frogs. Their populations are declining in many areas due to deforestation, however their nocturnal habits provide some protection against hunters. Several species are classified as threatened or endangered.
Examples of Aotidae Species
| Common Name | Scientific Name | Range |
|---|---|---|
| Douroucouli | Aotus infulatus | Central America and northern South America |
| Azara’s night monkey | Aotus azarae | South America east of the Andes |
| Three-striped night monkey | Aotus trivirgatus | Northwestern South America |
The Pitheciidae Family
The Pitheciidae family includes titis, sakis, and uakaris. There are over 40 species within this family. They inhabit various forest and savannah habitats of Central and South America.
Some notable features of Pitheciidae:
- Small to mid-sized monkeys
- Long, thick fur
- Non-prehensile tails
- Omnivorous diet, specializing in seeds and new growth
Prominent Pitheciidae genera:
- Titis – These monkeys have a distinctive appearance with a masked face and erect body posture. Social groups consist of 3-15 individuals.
- Sakis – As canopy specialists, sakis have adapted limb proportions for efficient climbing. They have unique fur colors and hair whorls.
- Uakaris – Bright red bald faces characterize this genus. They live in large groups of up to 100 individuals in Amazon flooded forests.
Several Pitheciidae species are under threat from habitat disturbance and hunting for bushmeat. The white-nosed saki and bald uakari are classified as Vulnerable.
Examples of Pitheciidae Species
| Common Name | Scientific Name | Range |
|---|---|---|
| Golden lion tamarin | Leontopithecus rosalia | Coastal Brazil |
| Monk saki | Pithecia monachus | Western Amazon basin |
| Red-faced uakari | Cacajao calvus | Western Amazon basin |
The Atelidae Family
The Atelidae family of Platyrrhini contains the howler, spider, woolly, and woolly spider monkeys. There are 24 species classified into 6 genera. Atelids are among the larger monkey species, with substantial size variation between genera. They inhabit tropical and subtropical forests from Mexico to Argentina.
Distinctive Atelidae characteristics:
- Large body size
- Long, prehensile tails
- Loud vocalizations, especially in howlers
Prominent Atelidae genera:
- Howler monkeys – Noted for their resonating vocalizations, these slow climbers eat leaves, fruit and flowers.
- Spider monkeys – Lanky and energetic monkeys with extraordinarily long limbs and prehensile tails.
- Woolly monkeys – Heavily furred with short snouts and a more leisurely style of locomotion.
- Woolly spider monkeys – As their name suggests, these monkeys share traits with spider monkeys and woolly monkeys.
Habitat disturbance is the major threat facing Atelidae populations. The black-headed spider monkey is classified as Critically Endangered with fewer than 250 mature individuals remaining.
Examples of Atelidae Species
| Common Name | Scientific Name | Range |
|---|---|---|
| Mantled howler | Alouatta palliata | Central America and northern Colombia |
| Geoffroy’s spider monkey | Ateles geoffroyi | Central America and tropical South America |
| Brown woolly monkey | Lagothrix lagothricha | Northern South America |
The Callitrichidae Family
The Callitrichidae family contains marmosets and tamarins, some of the smallest Platyrrhini monkeys. Most species weigh less than a pound. There are approximately 40 species classified into 15 genera. Callitrichids inhabit tropical forests from southern Mexico to northern Argentina.
Key features of this family:
- Small body size
- Clawed digits adapted for gripping (except pygmy marmoset)
- Twin births common
- Cooperative infant care by group members
Prominent Callitrichidae genera:
- Marmosets – The smallest monkeys, marmosets rely on tree gouging to harvest gum and sap.
- Tamarins – Distinguished by long tails and whiskered faces. Form bonded family groups.
- Goeldi’s monkeys – Closely related to callitrichids but classified in their own genus due to distinct traits.
Habitat loss and capture for the pet trade have led to population declines for many callitrichids. The cotton-top tamarin is classified as Critically Endangered.
Examples of Callitrichidae Species
| Common Name | Scientific Name | Range |
|---|---|---|
| Golden lion tamarin | Leontopithecus rosalia | Coastal Brazil |
| Pygmy marmoset | Cebuella pygmaea | Western Amazon basin |
| Pied tamarin | Saguinus bicolor | Northwest Brazil, southeast Colombia, east Peru |
Conclusion
The Platyrrhini are a diverse radiation of New World monkeys with over 150 species in 5 families. They demonstrate a wide range of adaptations to the forests and savannahs of Central and South America including variation in size, limbs, tails, fur, diets, and social systems. Prominent genera range from the tiny pygmy marmoset to the energetic spider monkeys. While the Platyrrhini have successfully exploited many ecological niches, they now face threats from an array of human activities. Habitat disturbance and hunting pressure have led to population declines and heightened extinction risk for many species. Protection of Neotropical ecosystems will be key to preserving Platyrrhini biodiversity into the future. Going forward, we can continue to deepen our understanding of this unique primate group through further scientific study and conservation initiatives.
