Scientists recreated the skulls of monkeys that lived six million years ago, and analyzed the area of their inner ear using three-dimensional computer tomography. This will help to study the evolution of human locomotion.
The results of a study published in the journal The Innovation show that it’s all about the semicircular canals. They are located between the brain and the outer ear and play an important role in ensuring balance during walking, writes Phys.org.
“The size and shape of the semicircular canals correlates with how mammals, particularly great apes and humans, moved through their environment.” – said Yinan Zhang, a doctoral student at the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences.
Terry Harrison, an anthropologist at New York University, states that the evolution of human locomotion (the transition from crawling to walking on two legs) occurred in three stages.
|Photo: Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences
“First, the earliest great apes moved around in trees in a style most similar to how gibbons in Asia do today.
Secondly, the last common ancestor of monkeys and humans was similar in its movements to Lufengpithecus (a genus of Asian great apes related to Sivapithecus and orangutan that died out in the Miocene – ed.). He used climbing and rock climbing, forelimb suspension, arboreal bipedalism, and terrestrial quadrupedalism.
It was from this wide repertoire of the motor apparatus of the ancestors that bipedalism (two-leggedness) of man developed”, – Harrison explained.
In most studies investigating the same question, scientists have compared the bones of the limbs, shoulders, pelvis, and spine, and how they relate to different types of motor behavior observed in living apes and humans.
However, the diversity of locomotor behavior in living great apes and the incompleteness of information on fossils prevented scientists from finding out the origin of human bipedalism.
|Three different views of the reconstructed inner ear of Lufengpithecus
Lufengpithecus skulls, discovered in the early 1980s in China’s Yunnan province, gave scientists another opportunity to study the evolution of human locomotion. But they were distorted and compressed. Because of this, scientists could not study the ears, which led their predecessors to believe that the semicircular canals were not preserved.
To obtain more informative results, the scientists used three-dimensional scanning technologies, with the help of which they created a virtual reconstruction of the skull and canals of the inner ear. These scans were then compared to scans of other living and fossil apes, as well as humans from Asia, Europe and Africa.
“Our analysis provides evidence that early great apes had a locomotor repertoire that was ancestral to human bipedal walking.
It appears that the inner ear is a unique carrier of the evolutionary history of ape locomotion and an invaluable alternative to the study of the postcranial skeleton.” – explained Sijun Ni, professor of the Chinese Academy of Sciences.
Studying the reasons for the evolution of locomotion, a group of scientists suggested that climate change could be one of them.
“The decrease in global temperature associated with the accumulation of ice sheets in the Northern Hemisphere around 3.2 million years ago is consistent with an increase in the rate of change of the bony labyrinth, and this may indicate a rapid increase in the rate of evolution of the musculoskeletal system in apes and humans.” – explained Terry Harrison.
We previously reported that a skull was found in China, which may belong to an unknown race of people.
Vira Shurmakevich, “UP. Life”
Read also: Scientists have dated the first references to romantic kisses to 2500 BC