Platyrrhini
The platyrrhines (Platyrrhini, from the Greek πλατυς, platys, 'wide', and ρινος, rhinos, 'nose') or new world monkeys are a parvorden that includes all five families of primates native to Central and South America, and tropical regions from Mexico: Cebidae, Aotidae, Pitheciidae, Atelidae and Callitrichidae. Publications such as MSW recognize the existence of 4 families, with Callitrichidae being considered a subfamily (Callitrichinae) of Cebidae. These five families are made up of 9 genera and 120 species, 20% of the recognized primate species.
Classification
This clade was classically considered to be made up of only two families Callitrichidae (formerly Hapalidae) and Cebidae. In 1980 Rosenberg redefined the families and expanded their number to five, as it is currently classified. Colin Groves in 2001, recognized only four families, placing Callitrichidae as a subfamily (Callitrichinae), within the family Cebidae, including the genera Callithrix, Saguinus, Leontopithecus and Callimico. Rylands and Mittermeier in 2009, places Callitrichidae as a separate family, additionally including the genera Cebuella, Callibella and Mico.
Location of platyrrhine families within primates:
- Order Primary
- Suborden Strepsirrhini
- Suborden Haplorrhini
- Infraorden Tarsiiformes
- Family Tarsiidae
- Infraorden Simiiformes
- Parvorden Platyrrhini:
- Family Callitrichidae
- Family Cebidae
- Aotidae family
- Family Pitheciidae
- Family Atelidae
- Parvorden Catarrhini
- Parvorden Platyrrhini:
- Infraorden Tarsiiformes
Origin
The American continent separated from Gondwana about 135 million years ago, while the origin of the Platyrrhines dates back to only about 40 million years ago, when the infraorder Simiiformes divided into the parvorden Platyrrhini (New World monkeys).) and Catarrhini (great apes and Old World monkeys). Taking this into account, it is believed that the individuals from which the numerous species of platyrrhines descended arrived in South America by means of biological dispersal in rafts formed by plant detritus. during tropical storms, either across the South Atlantic from Africa or across the Caribbean Sea from North America. However, there is no fossil record to support the North American migration hypothesis. Another possibility is the formation of a land bridge formed by several islands on an oceanic ridge in the middle of the Atlantic, combined with a decrease in sea level during the Oligocene, formations that could have served as stops during a possible migration. The Isthmus of Panama was not formed, so the ocean currents and the climate were very different from today.
The oldest platyrrhine fossil found in the New World is Branisella boliviana, from the Oligocene of Bolivia around 27 million years ago, with primitive characteristics reminiscent of catarrhines, making it probable that the origin and initial diversification occurred in Africa, before reaching the American continent through the Atlantic.
Since in North America there were only primitive forms such as adapiforms and plesiadapiforms, similar to the current lemurs that became extinct at the end of the Oligocene, the most consistent theory is that of a population of African origin that occurred in the late Eocene or early from the Oligocene, more or less at the same time that the ancestors of the South American rodents (chinchillas, maras, capybaras, guinea pigs, etc.) also arrived from Africa, perhaps even in the same migratory process. In any case, thereafter New World monkeys and Old World monkeys evolved in isolation from each other, meeting again when man arrived in the Americas around 15,000 years ago.
Physical characteristics and behavior
Platyrrhines are small to medium-sized primates, ranging in size from 13.6 cm in length to 119 g in weight in the pygmy marmoset, to the northern muriqui spider monkey which measures between 46 and 80 cm, with a weight of 9.5 to 15 kg depending on the sex.
Unlike catarrhine primates, platyrrhines, with the exception of the macaw (Cacajao spp.), have long tails in relation to their body mass and are frequently prehensile, as well as flattened snouts, with the nostrils in a lateral position. They feed mainly on fruits, which they supplement with leaves, insects, and small animals. Many species show territorial tribal organizations, and there are even associations of the groups of two different species such as the squirrel monkey and the capuchin, which in the case of the marmosets go as far as the joint defense of a common territory. In some species, the establishment of monogamous couples for life occurs, sharing the tasks of caring for the young, something rarely seen in catarrhines.
They generally inhabit moist, densely wooded intertropical areas. Massive deforestation has put their habitat at risk and threatened several species in recent years. Previously, its dispersal area ranged from the southern limit of the Chaco region and the Paraná jungle —approximately the latitude of the city of Buenos Aires— to the vicinity of the Tehuantepec isthmus and the Balsas River fault in southern present-day Mexico.
