“Fundamentally, the story of living apes is a mystery,” says Sergio Almecija, one of the authors of the new paper and a senior research fellow at the American Museum of Natural History in New York.
“There are no fossils that everyone agrees belong to the lineage of modern apes. At the same time, there are also a large number of fossils of great apes. But they are so different from living things that we have no idea what they are. No one agrees on that.”
The incomplete fossil fossil used in the study is from the only known example of Pierolapithecus, which was discovered 20 years ago. Landfill expansion It is located in northeastern Spain, part of which has since been turned into vineyards.
It may be difficult to imagine apes in this region. But millions of years ago, during the mid-Miocene, there were ten times as many great apes as there are today, and they were dispersed over a much wider geographic area, including parts of Asia and Europe.
Great apes of the mid-Miocene also lived in woodlands that were much less hot and humid than the tropical forests in which few great apes survive today, but all of them were endangered. or endangered.
However, the Miocene landscape changed.
About 9.6 million years ago, much of Eurasia’s evergreen forest habitat disappeared due to climate change. The loss was “tragic for the great apes,” he said. paper With natural education knowledge. In an extinction event known as the Valesian Crisis, most apes disappeared from the region.
Pierolapithecus was born “just before the Earth’s climate changed and many apes became extinct.”” said Carol Ward, a professor of pathology and anatomy at the University of Missouri School of Medicine, who was not involved in the paper.
Well-preserved fossils from this era are in short supply, Ward said. “The fossil record can be brutal. You get broken fossils, distorted fossils, fragmented fossils.”
So is the only set of remains from Clown Lapithecus. The bones, including a full face, part of a hand and pelvis, a foot, several vertebrae, and several ribs, were discovered when workers created a landfill near Barcelona that is now known as Avocado de Can Mata. Exposed.
“The face was slightly crushed in different directions,” Almecija said, adding that researchers initially believed the bone fragments were shaped while buried under tons of sediment over millions of years. He explained that he suspected that the structure had collapsed and bent.
However, during the process of reconstructing Pierolapithecus, researchers noticed that the bone fragments were not distorted. Many fell apart and separated from each other, leaving a kind of three-dimensional puzzle interrupted by missing pieces.
CT scans have been used for a long time. mid 2000s Reconstruct images of long-extinct animals, including: Sahelanthropus tchadensis, about 7 million years old, is one of the oldest known species assigned to the human family tree. But today’s instruments have much better resolution, allowing scientists to achieve results that would have been “nearly impossible” 10 years ago, Almesilla said.
The machine the scientists used to examine Pierolapithecus uses more powerful X-rays than traditional CT scanners found in hospitals. The device, known as a micro-CT scanner, can penetrate dense materials and produce images with much higher resolution.
Kelsey D. Pugh, a researcher at the American Museum of Natural History and a lecturer at Brooklyn College, led the CT analysis of Pierolapithecus..
“As part of the reconstruction, we will need to do a CT scan of this damaged specimen to determine what is bone and what is rock,” Pugh said. “You have to decide which fragments to leave with which others.”
After assembling the bone sections, Pugh said she had to find the correct position for each piece, a process that took months and required “a lot of anatomical knowledge and a little bit of skill.” It is said that it was. One technique, called “mirror imaging,” took advantage of the symmetry of the skull. When there were no fragments on the left side of the skull, she guessed what they should look like based on the fragments present on the right side.
Scientists determined they were looking at a male Pierolapithecus based on the large size of its pointed teeth, called canines.. It weighed about 75 pounds, making it about the same size as a modern-day female chimpanzee.
“The big surprise was that it was a mosaic,” Almecija said.
Pierolapithecus occupies an important branch of the tree of life, with a face similar to the great apes we know today, such as orangutans, chimpanzees, and gorillas, and short hands like apes. Modern apes have long hands that allow them to “hang under branches using long, curved fingers like hooks,” he said.
Almesilla said Pierolapithecus’ torso is similar to that of modern apes and humans, and its upright posture helps humans walk on two legs and helps apes climb and hang from tree branches. “Monkeys have more primitive bodies. [form], like cats and dogs. ”
Pugh said the most distinctive feature of Pierolapithecus was the height of its face, particularly the distance between the areas of the skull that house the eyes and nose. The eyes are “quite high on the face,” Pugh said. “This is a feature that is also seen in other fossil apes, but it is higher than in most modern apes.”
“Detailed reconstructions of this species are valuable, but require a huge amount of effort,” said Kieran McNulty, a professor of anthropology at the University of Minnesota who was not involved in the study.
McNulty said the study’s authors made the CT scans of Pierolapithecus available to other scientists, which is relatively rare in paleontology and paleoanthropology. This allows other teams to try to rebuild their own species..
For scientists studying the evolution of hominids and primates, including humans, the reconstruction and similar studies should further our understanding of the changes that have occurred over millions of years of great ape evolution.
That would lead to “very interesting questions about why these changes occurred.” Ward said. “Then start putting the story together.”
