Ancient, fossilized teeth, to unveil the decades-long archeology project in northeastern Ethiopia, shows that two different species of hominin or human ancestors lived in the same place from 2.6 to 2.8 million years-and one of them may be previously unknown species.
This discovery gives you a new look at the complex human evolution network. The ten teeth set for 2018-2020 belong to the Australopithecus genus, a relative of the ancient man. Meanwhile, three teeth found in 2015 are owned by the Homo tribes, which belong to modern people or Homo sapiens. The results were published on Wednesday in Nature magazine.
Such a coincidence of two hominins in the excavation record is rare, which has previously encouraged scientists to believe that homo appeared after Australopithecus, not both were contemporaries. Australopithecus species walked vertically like modern people, but had a relatively small brain closer to size rather than monkeys. The emergence of homo species with larger brains today is easy to view as a certain evolutionary update on the road to modern humanity.
However, both coexistences indicate that hominines have evolved and lived in various varieties at the same time. “This new study shows that the image that most of us have in our minds, that the Neanderthals are not correct for the modern man – evolution does not work as follows,” said the research co -author Kaye Reed, research scientist and presidential professor Emerita, Empter Extrins and Emerito Professor at Human Evolution and Social Strions at Arizona. By mail. “Here we have two types of hominin that are together. And human evolution is not a linear, it is a shrub tree, there are life forms that disappear.”
Since 2002 Reed was a codgetor of the Ladi-Geerar research project partially oriented towards the search for evidence of early homo types. 2015 The team announced the discovery of the oldest known Homo Jawbone at 2.8 million years. She was also looking for later evidence of Australopithecus Afarensis, which first appeared in 3.9 million years ago, but after 2.95 million years of these ancient relatives, there are no signs to dig the first homo show.
Australopithecus Afarensis best represents the most famous fossilized Lucy remains found in 1974. In Ethiopia. Lucy was shorter than the average person with a height of about 3.3 feet (1 meter), had a naked face and brain in about a third of the human brain size. Her fossil demonstrated many similar and similar features and provided proof that the relatives of the ancient people walked vertically 3.2 million years ago.
When the team discovered Australopithecus teeth in two separate excavations in 2018 and 2020, it compared them to species such as Afarensis and other hominino group known as Garhi, but they do not match. Instead, scientists believe that teeth belong to previously unknown species of Australopithecus, who walked around the Earth after Lucy – and along with early homo species.
“When we found homo, I thought it was all we found, and then one day we found Australopithecus teeth in a survey,” Reed said. “Most importantly, it once again demonstrates that human evolution is not linear. There were species that have disappeared; some were better applied than others and others intervened with us – we really know it for Neanderthals.
The teeth marked with LD 750 and LD 760 reflect the unknown species of Australopithecus, while LD 302-23 and AS 100 of the early homo species. – Brian Villmore/Nevada University, Las Vegas
Cracks on the ground
Teeth were found in the Afar region of Ethiopia – the main place for researchers looking for answers about human evolution. Various canned fossils were found there, as well as some of the earliest stone tools, Reed said.
The AFAR region is an active re -environment – tectonic plates under it on the ground, actively retreating and revealing older sediment layers that emit nearly 5 million years of evolution, Reed said.
“The continent there is literally, which creates a lot of volcanism and tectonics,” said the co -author of the study Christopher Campisano, an associate professor and associate professor at the Arizona State School, published in the school of human evolution and social change at school. “2 1-2, 3 million years ago, these volcanoes have pushed ash containing crystals called outdoor brushes that allow us to see the eruptions in the landscape when they are deposited.”
Australopithecus teeth recorded in the new study were dated 2.63 million years ago and homo teeth are between 2.59 and 2.78 million years. However, the team carefully determines the species of any type of teeth until it has more data and more fossils.
“We know what the earliest Homo teeth and lower jaws look like, but that’s it,” said Brian Villmare, chief study author and associate professor of Las Vegas Anthropology at the University of Nevada. coincide in the fossil post in the same place. ”
Australopithecus teeth are essentially similar to the contour of Afarensis species and the size of the moles, but the features of the hood and dog teeth were not previously visible afrensis or Garhi teeth, said Villmoare. The teeth also differed from any type of homo or ancient human relative parantropic, known for its large teeth and chewing muscles.
“Obviously, these are just teeth,” said Villmoare, “but we continue to work out of the field in the hope of recovering other parts of the anatomy that can increase the resolution of taxonomy.”
According to Campisano, even teeth finding was a difficult task.
“You look at small teeth, quite literally, individual teeth that look just like many other small pebbles spread out in the landscape,” he said in the video. “So, we have a great team of local Afars that are great fossil hunters. They saw these things throughout their lives walking around the landscape.”
This year, the Ladi-Geera Research Project Team, which is digging this year, is looking for evidence of early homo species. – AMY Rector/Virginia Commonwealth University
A burst of evolution
The new study is important because it provides insight into the period of about 3 million to 2 million years, a mysterious period of human evolution research, said Stephanie Melill, a paleoanthropologist and associate professor at the University of Mercyhurst, Pennsylvania. Melillo did not participate in this study, but she participated in the Worans-Mille Paleontological Research Project in the Afar Ethiopian Triangle.
Part of the problem associated with this prehistoric stretch is how the ancient layers of dirt have been settled through history in East Africa.
“Erosion in rivers and lakes was low level and only a little dirt was deposited from afar,” Melillo wrote. In the letter. “That deposited dirt contains fossils – our ancestors and all the animals living with us. When there is little deposition, there are few fossils.”
The main feature that helps archaeologists understand the evolution of humanity is structural pools or “bowls” on the surface of the earth, which naturally collect sediment layers better than the surrounding landscape – like the Turkana pool, which extend through southern Ethiopia and northern Kenya. Previous studies found evidence that homo and paranthropus existed there 1.5 million years ago.
In the new study, the focus is on further depression, the pool north of Turkana.
“This contribution of Villmore and colleagues shows that there were several other types of homo, but it is not parantropus,” Melill said. They do a very convincing job by showing why the new fossils are not parantropes. “
The study adds increasing evidence that Australopithecus is not true of depression alone, she said.
The Lead-Gear is a Paleontology team project looking for a FOSILS Afar region in the Lee Adoyta basin. – Kaye Red/Arizona State University
Mysterious coexistence
When Australopithecus and Homo were alive, Afar, now mostly half -half, was a lot of seasonal rainfall differences than today, said Reed. Millions of years ago, a dry season was still dominated by the environment, but it was interrupted by a short humid season. The rivers carrying water through the landscape existed only for a part of the year. There were few trees near the river, and the nearby environment were mostly swamp and meadow.
“We have a fossil giraffe type that eaten grass, which probably shows that they were stress when they eat trees and shrubs in almost every place,” the Reed said. “Has hominines ate the same thing? We are trying to find out by examining the tooth and microscopic scratches on the teeth.”
Understanding whether homo and Australopithecus had the same food sources or not could draw a portrait as our ancient ancestors shared or competed for resources, Reed said. The team also wants to try to find out which hominin made stone tools found on the site.
At this point, it is impossible to say exactly how both hominines existed, but Reed said they expect future conclusions to provide more answers.
“Whenever you have an interesting discovery, if you are a paleontologist, you always know that you need more information,” Reed said. “You need more fossils. More fossils will help us tell us a story about what happened to our ancestors, but because we are surviving, we know that it happened to us.”
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