ORRORIN TUGENENSIS: DISCOVERY, CHARACTERISTICS, SKULL - BIOLOGY - 2025

The orrorin was one of the first species of hominids (primate families) that was part of the first living things belonging to the lineage of humans.

Some scientists have the theory that these creatures gave direct passage to the evolution of Homo sapiens. Despite this, this species lacks many characteristics present in humans.

Place of discovery of the species, By Chartep, from Wikimedia Commons

He is also called "Man of the Millennium" due to the year in which he was discovered. The Orrorin Tugenensis is the only species belonging to the Orrorin family.

On the other hand, the appearance of Orrorin Tugenensis was an argument against the theory that Australopithecus afarensis is the ancestor of Homo sapiens; however, research is still being carried out to understand its participation in the evolution of the human being.

Discovery

First fossils

The first discovery of this species occurred in 2001, in the Lukeino Formation localities of the Tugen Hills, located in Kenya (Africa).

The person responsible for its discovery was a paleontological group, led by the French doctor Brigitte Senut and the English geologist Martin Pickford. Researchers were on a tour of the area when they found fragments of the species' jaw, teeth and some parts of the skull.

In addition to the skull bones, the scientists also found fragments of the leg bones of these creatures. In total, the researchers found more than a dozen remains of this type.

Since the first discovery, other scientists have found at least two dozen additional fossil remains since 2007.

Identification of the species

Despite being identified at first as a species belonging to the genus Homo sapiens, some experts in paleontology assured from the beginning that it did not belong to this family. They assured that the primate species came to live more than 6 million years ago.

However, different tests and analyzes showed that it is a species much more similar to Homo sapiens compared to Australopithecus afarensis, a hominid that lived about 3.9 million years ago and that was considered one of the predecessor species of the human being.

A particular aspect is that this species has a mixture of characteristics typical of human beings and others that belong to other species of primates.

Physical and biological characteristics

Teeth

The structure of the Orrorin Tugenensis teeth is morphologically similar to that of other primate species. This prompted assumptions on the part of scientists, who thought that this species' similarities to apes might include the ability to stand on two of its feet; skill known as standing.

The species had small teeth compared to its body size. The canines had a similar structure to those of the apes, but they had a smaller size; in addition, they had other even smaller canines. This last characteristic coincides with the dental structure of humans.

Legs

The femoral bones found refute the theory that the Orrorin Tugenensis could have walked with only two of its limbs.

The elongated and compressed femoral neck at the back, as well as a thicker cortex at the bottom compared to the top of the bone is part of the similar features with other hominin beings.

Furthermore, the presence of a particular groove on the bone structure and the prominence in the buttock area are also features that support the theory; however, asymmetry in bone distribution is one of the most distinctive elements that indicates the probability that it could walk with two of its extremities.

The size of its bones suggests that this species was 1.5 times larger than Australopithecus. In addition, it shows that the average weight of this type of living being could be between 30 and 50 kilograms.

Hands

Other fossil remains of the Orrorin Tugenensis were part of the humerus, a proximal phalanx and a phalanx of the thumb. The different analyzes to these parts also refuted the theory that it was the ancestry of Homo sapiens because of its resemblance to other primate species.

Cranial capacity

Recent studies

Because the discovery of the Orrorin Tugenensis was relatively few years ago, there is still no concrete information on many aspects of its morphology. The cranial capacity of this species is not yet a verified data.

However, assumptions that this living being could be the size of a chimpanzee would lead to the hypothesis that the cranial capacity is also similar to that of this mammal.

Habitat

Forests and savannas

Little information exists regarding the habitat of the Orrorin Tugenensis; However, some theories based on the structure of their bones and their similarity with other species of primates suggest that the habitat of this species would be centered in forests and savannas.

Lifestyle

Feeding

The shape of their teeth indicates that this species of primates had a herbivorous and frugivorous diet; however, the possibility that they were also able to maintain an omnivorous diet to have a protein source was not ruled out.

Among the items it used for food were leaves, fruits, seeds, roots, some nuts and probably some insects.

Mobilization

The shape of the phalanges of the hands of this primate species and the bone structure of the humerus indicate that this species moved by climbing the branches of trees.

Despite this, the theory is maintained that at certain times the primates had to stand on two of their limbs to be able to move over the trees and reach objects, a skill that could be adopted to apply it to the ground.

This theory was supported by the scientists after all the morphological analyzes carried out on the femur remains found, which yielded bone data; the rounded shape of the upper part of the bone was able to support the weight of the trunk of the body and the upper extremities.

For this reason, the shape of the femur fragments found indicates that the Orrorin Tugenensis could have maintained an upright posture on two of its legs, managing to carry out other movements.

References

1. Orrorin Tugenensis, Natalia Acevedo and Javier Rosique, Portal Aprende en Línea, (2016). Taken from aprendeenlinea.udea.edu.co
2. The Earliest Hominins: Sahelanthropus, Orrorin, and Ardipithecus; Denise F., Portal Knowledge Project, (2013). Taken from nature.com
3. Travel to our origins: the path of evolution, National Geographic Portal, (nd). Taken from nationalgeographic.com.es
4. Physical Anthropology - Orrorin tugenesis, UPEL Anthropology and Ecology Portal, (2011). Taken from antropologiayecologiaupel.blogspot.com
5. Orrorin tugenensis, Portal Smithsonian National Museum of Natural History, (nd). Taken from humanorigins.si.edu
6. Orrorin, Wikipedia in English, (nd). Taken from wikipedia.org
7. Orrorin tugenensis, Portal EOL Encyclopedia of life, (nd). Taken from eol.org