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THE primate evolution and its origin it has caused a great deal of controversy and a multitude of hypotheses since the beginning of these studies. This extensive Order of mammals, to which people belong, is one of the most threatened by humans.
In this article by PeritoAnimal, we will learn who primates are, what characteristics define them, how they evolved and if it is the same thing to talk about monkeys and primates. We'll explain everything below, keep reading!
Origin of primates
THE primate origin is common to all. All existing species of primates share a set of characteristics that distinguish them from the rest of mammals. Most existing primates live in trees, so they have concrete adaptations that allow them to lead this lifestyle. your feet and hands are adapted to move between the branches. The toe of the foot is very separate from the other toes (with the exception of the human being), and this allows them to hold on firmly to the branches. The hands also have adaptations, but these will depend on the species, such as the opposable thumb. They do not have curved claws and nails like other mammals, they are flat and without points.
the fingers have tactile pillows with dermatoglyphs (fingerprints) that allow them to better attach to the branches, in addition, on the palms of the hands and fingers, there are nerve structures called Meissner corpuscles, which provide a highly developed sense of touch.The body's center of gravity is closer to the legs, which are also the dominant members during locomotion. On the other hand, the heel bone is longer than in other mammals.
One of the most important adaptations in primates is the eyes. First, they are very large in relation to the body, and if we are talking about nocturnal primates, they are even larger, unlike other nocturnal mammals that use other senses to live at night. Those prominent eyes and large ones are due to the presence of a bone behind the eye, which we call the orbit.
In addition, the optic nerves (one for each eye) do not completely intersect within the brain, as they do in other species, in which information entering the right eye is processed in the left hemisphere of the brain and information entering the left eye is processed in the right side of the brain. This means that, in primates, the information that enters through each eye can be processed on both sides of the brain, which provides a much broader understanding of the environment.
The primate ear is characterized by the appearance of a structure called the auditory ampulla, formed by the tympanic bone and the temporal bone, involving the middle and inner ear. On the other hand, the olfactory sense seems to have been reduced, with smell no longer being a hallmark of this group of animals.
As far as the brain is concerned, it is important to emphasize that its size is not a determining feature. Many primates have smaller brains than any average mammal. Dolphins, for example, have their brains, compared to their bodies, almost as large as any primate. What differentiates the brain from primates are two anatomical structures unique in the animal kingdom: the Sylvia's groove it's the calcarin groove.
THE jaw and teeth primates have not undergone major changes or adaptations. They have 36 teeth, 8 incisors, 4 canines, 12 premolars and 12 molars.
Types of primates
Within the taxonomic classification of primates, we find two suborders: the suborder "strepsirrhini", to which the lemurs and lorisiforms belong, and the suborder "Haplorrhini", which includes the tarsiers and monkeys.
strepsirrhines
Strepshyrins are known as wet nose primates, your sense of smell has not diminished and remains one of your most important senses. This group includes the lemurs, inhabitants of the island of Madagascar. They are famous for their sonorous vocalizations, their large eyes and their nocturnal habits. There are about 100 species of lemurs, including the lemur catta or ring-tailed lemur, and the alaothra lemur, or Hapalemur alaotrensis.
another group of strepsirrhines they are the loris, very similar to lemurs, but inhabitants of other areas of the planet. Among its species we highlight the loris red thin (Loris tardigradus), a highly endangered species from Sri Lanka, or the loris slow of Bengal (Nycticebus bengalensis).
haplorrhine
Halplorrine are simple nose primates, they lost part of their olfactory ability. A very important group is the tarsiers. These primates live in Indonesia and are considered devilish animals because of their appearance. Of nocturnal habits, they have very large eyes, very long fingers and a small body. both groups strepsirrhine and the tarsiers are considered prosimians.
The second group of haplorrhine are monkeys, and they are generally divided into New World monkeys, Old World monkeys, and hominids.
- new world monkeys: all these primates live in Central and South America. Their main characteristic is that they have a prehensile tail. Among them we find howler monkeys (genus Alouatta), the nocturnal monkeys (genus Aotus) and spider monkeys (genus Atheles).
- old world monkeys: these primates inhabit Africa and Asia. They are monkeys without a prehensile tail, also called catarrhines because they have their nose down, and they also have calluses on the buttocks. This group is formed by baboons (genus Theropithecus), monkeys (genus monkey), cercopithecines (genus Cercopithecus) and colobus (genus colobus).
- hominids: they are tailless primates, also catarrhine. The human being belongs to this group, which he shares with the gorillas (genus gorilla), chimpanzees (genus pan), bonobos (genre pan) and orangutans (genus Pong).
Interested in non-human primates? See also: Types of monkeys
primate evolution
At primate evolution, the fossil most closely related to modern primates or primates dates from the late Eocene (about 55 million years ago). In the early Miocene (25 million years ago), species very similar to today's began to appear. There is a group within primates called plesiadapiform or archaic, Paleocene primates (65 - 55 million years) that show certain primate characteristics, although these animals are currently considered to have diverged before the appearance of primates and later became extinct, so they would not be related to them. .
According to the fossils found, the first primates Known ones are adapted to arboreal life and have many of the main features that distinguish this group, such as the skull, teeth and skeleton in general. These fossils have been found in North America, Europe and Asia.
The first fossils from the Middle Eocene were found in China and correspond to the first primate relatives (Eosimians), which are now extinct. Fossil specimens belonging to the extinct families Adapidae and Omomyidae were later identified in Egypt.
The fossil record documents all existing groups of primates, with the exception of the Malagasy lemur, which has no fossils of its ancestors. On the other hand, there are fossils from its sister group, the lorisiformes. These remains were found in Kenya and are about 20 million years old, although new discoveries show that they existed 40 million years ago. Therefore, we know that lemurs and lorisiformes separated more than 40 million years ago and form a suborder of primates called strepsirrhines.
The other suborder of primates, the haplorrhines, appeared in China in the Middle Eocene, with the tarsiiformes infraorder. The other infraorder, the apes, appeared 30 million years ago in the Oligocene.
O emergence of the genus Homo, to which the human being belongs, occurred 7 million years ago in Africa. When bipedalism appeared is still unclear. There is a Kenyan fossil of which only a few long bones remain that may suggest a certain bipedal locomotion ability. The most evident fossil of bipedalism is from 3.4 million years ago, before the famous Lucy fossil (Australopithecus afarensis).
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