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The Independent
2 days ago
- Science
- The Independent
Fossil teeth lead to discovery of human species that lived alongside our oldest ancestors
Fossil teeth unearthed in Ethiopia suggest two distinct human ancestor species lived alongside each other between 2.6 and 2.8 million years ago, reshaping what is known about our evolution. The 13 teeth come from a Homo species that lived in Ethiopia's Afar region, overlapping with the hominin ancestor Australopithecus. The teeth, found at the Ledi-Geraru archaeological site, reveal that the oldest members of the Homo genus coexisted with the Australopithecus. 'These specimens suggest that Australopithecus and early Homo coexisted as two non-robust lineages in the Afar region before 2.5 million years ago,' researchers said, 'and that the hominin fossil record is more diverse than previously known.' According to Kaye Reed, a co-author of the study, the discovery shifts our perception of human evolution. "Here we have two hominin species that are together. And human evolution is not linear, it is a bushy tree, there are lifeforms that go extinct,' Dr Reed explained. 'This new research shows the image many of us have in our minds of an ape to a Neanderthal to a modern [human] is not correct. Evolution doesn't work like that.' Analysis of the teeth, published in the journal Nature, shows they belonged to a new Homo species rather than Australopithecus afarensis – represented by the famous ' Lucy' specimen – which last appeared 2.95 million years ago. 'The new finds of Homo teeth from 2.6 to 2.8 million-year-old sediments confirm the antiquity of our lineage,' Brian Villmoare, lead author of the study, said. The newly discovered ancestor species does not have a name yet. More fossils are needed for that to happen. Researchers dated the specimen based on the fossil site's volcanic and tectonic activity. The region is home to many volcanoes that spew ash containing crystals called feldspars. "We can date the eruptions that were happening on the landscape when they are deposited," Christopher Campisano, another author of the study, explained, referring to feldspars. "And we know that these fossils are interbed between those eruptions, so we can date units above and below the fossils. We're dating the volcanic ash of the eruptions that were happening while they were on the landscape.' Examining the fossils and the landscape together allowed researchers to recreate the environment millions of years ago. They found that the landscape traversed by these ancient human ancestors 2.6 to 2.8 million years ago was a stark contrast to modern times. Back then, rivers flowed through a vegetated landscape into shallow lakes that expanded and contracted over time. "The geology gives us the age and characteristics of the sedimentary deposits containing the fossils,' said another study author Ramon Arrowsmith. 'It is essential for age control.' It remains unclear if the Lucy species and the Australopithecus species ate the same things and competed with each other for food. In further studies, researchers hope to examine the tooth enamel of the species to find out what they ate.
Yahoo
2 days ago
- Science
- Yahoo
Ethiopian fossils reveal new species in human evolutionary lineage
By Will Dunham (Reuters) -Researchers have unearthed tooth fossils in Ethiopia dating to about 2.65 million years ago of a previously unknown species in the human evolutionary lineage, one that lived in the same time and place as the earliest-known member of the genus Homo to which our own species belongs. The scientists discovered in the Ledi-Geraru research project area of northeastern Ethiopia's Afar Region 10 teeth - six molars, two incisors, one premolar and one canine - that they concluded belonged to a new Australopithecus species. The teeth came from two individuals. Until now, six species of the genus Australopithecus, an important early human ancestor that displayed a mix of ape-like and human-like traits, were known from fossils at various African sites. The researchers said the newly found teeth bore traits indicating they belonged to a seventh species. A genus is a group of closely related species that share similar characteristics. For example, lions and tigers are from the same genus but represent different species. The scientists also discovered three other teeth dating to 2.59 million years ago that had traits showing they belonged to the oldest-known species of Homo, one that was first revealed by a jawbone unearthed in the same vicinity in 2013. Scientists have not yet assigned names to the Australopithecus and Homo species represented by these 13 teeth because of the incomplete nature of the fossil remains. Our species Homo sapiens is the most recent member of the Homo genus, first appearing roughly 300,000 years ago in Africa before later spreading worldwide. The new dental fossils provide insight into a poorly understood period in human evolution. The close age of the teeth suggests that this newly identified Australopithecus species coexisted in this region with the early Homo species, raising questions about whether they competed for the same resources. The teeth also indicate that there were four hominins - as species in the human evolutionary lineage are known - that inhabited East Africa at the time. Previous fossils showed that another Australopithecus species and a species of Paranthropus, a hominin possessing a specialized skull adapted for heavy chewing, lived in East Africa during this time. An additional Australopithecus species also inhabited southern Africa, bringing the number of hominins then on the continent to five. The presence of these contemporaneous hominins illustrates the complicated nature of the human evolutionary process. "This reinforces the idea that the story of human evolution is not of a single lineage changing slowly through time," said University of Nevada, Las Vegas paleoanthropologist Brian Villmoare, lead author of the research published on Wednesday in the journal Nature. "Rather, the pattern of human evolution is similar to that of other organisms, repeatedly branching into multiple species throughout the fossil record, many of whom lived at the same time," Villmoare added. The researchers are seeking clues about the nature of any interaction between the Australopithecus and Homo species represented by the 13 teeth. "We are currently analyzing teeth to see if we can tell if they ate the same thing," said Arizona State University paleoecologist and project co-director Kaye Reed. If so, they may have fought over resources, Reed said. Crude stone tools dating to about the same time were previously discovered nearby, Reed said, probably made by the Homo species. The researchers determined the age of the teeth using a technique that dated feldspar crystals contained in volcanic ash in the sediments where they were discovered based on radioactive decay of the element argon. The Afar Region, one of Earth's hottest and lowest places, is an arid expanse of badlands. But at the time of these species, rivers flowed across a vegetated landscape into shallow lakes in a landscape populated by a splendid array of animals. These included giraffes, horses, pigs, elephants, hippos and antelopes as well as predators such as saber-toothed cats and hyenas. Homo is generally thought to have descended from a species of Australopithecus, though the exact species and the timing have been a matter of debate. Australopithecus eventually died out. Australopithecus includes the famous fossil Lucy, who was a member of the species Australopithecus afarensis who lived approximately 3.18 million years ago. Lucy's remains were discovered in 1974, also in the Afar Region. The newly discovered teeth had characteristics that showed they did not belong to Lucy's species, the researchers said. "This new Australopithecus species is in no way some 'missing link,' and we actually don't think that it was necessarily ancestral to any known species," Villmoare said. "Species arose and many went extinct," Reed said. "Each find is a piece of the puzzle that puts human evolution into a twiggy tree, rather than a linear graphic." Solve the daily Crossword
Yahoo
07-07-2025
- Science
- Yahoo
Pulsing Magma in Earth's Mantle Drives Tectonic Plates Tearing Africa Apart
A spot in eastern Africa called the Afar Triangle marks the meeting point of three rift zones—lines where Earth's crust is being rent apart. Researchers haven't been sure exactly what drives this rifting, but a new study in Nature Geoscience suggests it is caused by rhythmic pulses of molten rock from deep below the surface. Scientists first proposed in the 1970s that a hot upsurge of material from Earth's mantle, known as a plume, was occurring below this spot. Since then researchers have debated whether a single plume, multiple smaller 'plumelets' or something else entirely is pushing the plates apart. Emma Watts, a geochemist at Swansea University in Wales, wanted to settle the question, so she and a team of geophysicists, geochemists and computational scientists put their heads together and came up with a likely answer. 'The more I look into it, the more I see that you've got to have all the pieces of the puzzle to see the big picture,' she says. [Sign up for Today in Science, a free daily newsletter] The team analyzed 130 rock samples from volcanoes in the Afar region. Chemical signatures from each sample helped the scientists piece together the movement of the molten rock below Earth's surface: The researchers calculated the ratios of concentrations of elements such as lead and cerium, which can indicate whether deep mantle material has surged upward, as well as the ratios of different isotopes that each originated from slightly varying reservoirs within the mantle. After comparing their data to computational models of various permutations of mantle plumes, the researchers have found that the best explanation for their observations is a single plume that moves upward in pulses. The pulses appear to exert varying pressure that pushes on each rift zone differently, depending on the way the rift moves and the thickness of the crust on either side. The Afar Triangle's fast-spreading Red Sea Rift has pulses that move farther along the rift zone and that are more frequent than those of the slower-spreading Main Ethiopian Rift in the western part of the triangle. 'The rifting rates are really controlling what we're seeing in the plume,' Watts says. 'What we think is that [the Red Sea Rift is] spreading out faster..., so it has more space to move, and it's being stretched out easier.' The relationship between the mantle movement and the geochemical fingerprints is 'exciting because it suggests geophysics and geochemistry can be married to infer large-scale geodynamic processes,' says Catherine Rychert, a geophysicist at the Woods Hole Oceanographic Institution, who was not involved in this research. This is one of the first known examples of a dynamic mantle plume that responds to the tectonic plates above, so more research is needed to confirm the finding, Rychert says. Watts hopes this technique could be used in other rift systems and that more data from this system could give researchers a more precise view of what is happening deep below Earth's surface.
Times
25-06-2025
- Science
- Times
How a plume of magma threatens to one day rip east Africa apart
Africa is being torn apart by a pulsing plume of magma rising from deep within the Earth that is set to slice off the continent's east coast to form a new ocean, researchers have found. A new ocean basin will gradually form in a low-lying region of Ethiopia and, in several million years' time, scientists believe this will develop into a vast crack running from northern Ethiopia down to the middle of Mozambique. This could result in a 3,200-mile stretch of the east African coast, extending several hundred miles inland, splitting from the rest of the continent as the tectonic plate stretches, thins and eventually ruptures 'almost like soft plasticine'. This would leave a narrow ocean between continental Africa and a vast new island made up of present-day Somalia and large parts of what are now Ethiopia, Kenya, Tanzania and Mozambique. The Afar region of Ethiopia is a rare area where three tectonic rifts converge: the Main Ethiopian, Red Sea and Gulf of Aden rifts. Geologists had suspected that a 'hot upwelling' of molten mantle, often known as a plume, was rising up from between 620 and 1,700 miles deep, shooting upwards and melting the continental crust, weakening and thinning it. Researchers from the University of Southampton collected more than 130 samples of volcanic rock from the Afar region and Main Ethiopian Rift. They used modelling to understand the structure of the crust and mantle in the area. They found that beneath the Afar region there was an asymmetrical plume coming up out of the mantle, with patterns that differed in each of the three rifts. 'We found that the mantle beneath Afar is not uniform or stationary — it pulses, and these pulses carry distinct chemical signatures,' said Dr Emma Watts, lead author of the study who is now at Swansea University. 'These ascending pulses of partially molten mantle are channelled by the rifting plates above.' The results suggest the plume is 'pulsing like a heartbeat', said Tom Gernon, a professor of Earth science at Southampton. 'These pulses appear to behave differently depending on the thickness of the plate, and how fast it's pulling apart. In faster-spreading rifts like the Red Sea, the pulses travel more efficiently and regularly like a pulse through a narrow artery.' When a hot plume of magma rises from deep within the Earth it flows beneath the base of the tectonic plates and helps to 'focus volcanic activity to where the tectonic plate is thinnest'. 'This has profound implications for how we interpret surface volcanism, earthquake activity and the process of continental break up,' said Dr Derek Keir, a co-author of the study, which is published in the journal Nature Geoscience. Gernon said that part of the Afar region was about 120 metres below sea level and had been flooded by the sea several times in the past, including 80,000 years ago, as shown by salt deposits in the area. 'The formation of a fully developed ocean and mid-ocean ridge — that is, a plate tectonic feature where new ocean crust is created — in this region is likely to take several million years,' he said.
