Archive for the ‘paleoanthropology’ Category

We probably don’t descend from Australopithecus sediba

May 21st, 2019
Photo of A. sediba skull.

Enlarge / According to Du and Alemseged, A. sediba is probably not our direct ancestor. (credit: Brett Eloff courtesy Profberger and Wits University)

Sometime around 2 million years ago, a group of bipedal hominins in Eastern Africa gradually evolved into something that looked and acted enough like us to be part of our genus, Homo. This was an important moment in the evolutionary history of our species, but paleoanthropologists aren’t sure yet exactly which species actually gave rise to our branch of the hominin family tree. A new study, however, suggests that we can probably rule out one of the contenders.

Where did we come from?

The top contenders include a species called Australopithecus sediba, known from the fossilized remains of two adults and four children who apparently fell to their deaths in Malapa Cave around 1.9 million years ago. The other top contender is called A. afarensis, best known from the 3.2-million-year-old skeleton nicknamed Lucy and a set of preserved footprints near Laetoli, Tanzania.

Both species walked on two legs and probably made stone tools, but their shoulders, arms, and hands were also still built for climbing trees. So which species is actually our ancestor, and which is just a distant cousin?

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Posted in anthropology, Archaeology, australopithecus, hominins, human evolution, lucy, paleoanthropology, science | Comments (0)

Finally, a Denisovan specimen from somewhere beyond Denisova Cave

May 1st, 2019
Photo of archaeological excavations in karst cave.

Enlarge / The entrance of the cave is relatively flat with a gentle slope up to the inside, where two small trenches were plotted in 2018. (credit: Dongju Zhang, Lanzhou University)

Denisovans, an extinct group of hominins that once walked alongside (and had sex with) Neanderthals and modern humans, are an enigmatic branch of our family tree. They left fragments of their DNA behind in modern human genomes across Asia, Australia, and Melanesia. But their only physical remains seem have been left in Denisova Cave in Siberia: just a finger, a few molars, a fragment of arm or leg bone, and a small chunk of skull.

But we’re starting to piece together a little more of our mysterious cousins’ story. A team of paleoanthropologists recently identified a new Denisovan fossil—half of an entire jaw. And it comes from the high altitude of the Tibetan Plateau in northern China, nearly 2,000km (1,200 miles) from Denisova Cave.

An accidental find

Half a lower jaw and a few teeth may not sound like much, but it’s one of the largest pieces of a Denisovan skeleton that we know of so far. Its owner died at least 160,000 years ago, according to uranium-series dating of a thin crust of carbonate on the fossil, so the Denisovan from Tibet is about the same age as the oldest Denisovan unearthed so far at Denisova Cave.

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Meet your long-lost distant cousin, Homo luzonensis

April 10th, 2019
Callao Cave in northern Luzon, where the fossils were found.

Enlarge / Callao Cave in northern Luzon, where the fossils were found. (credit: Detroit et al. 2019)

Our picture of hominin evolution in Asia just got more complicated, thanks to the discovery of a previously unknown hominin species on the island of Luzon in the Philippines. The new species, Homo luzonensis, lived at around the same time as the “Hobbits” of nearby Flores (Homo floresiensis).

The two species share a mix of modern and older traits. Homo luzonensis’ teeth look like those of more recent members of our genus, Homo, but the hand and foot bones look more like they could have belonged to an Australopithecine—an early human relative that evolved around 3 million years ago and spent as much time in the trees as on the ground, a group that includes the famous skeleton named Lucy.

The combination didn’t look like any other species anthropologists had seen before.

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Posted in anthropology, Archaeology, Hominin, hominins, homo erectus, homo floresiensis, homo luzonensis, human evolution, out of africa, paleoanthropology, science | Comments (0)

Climate change may have driven a band of Neanderthals to cannibalism

March 31st, 2019
Climate change may have driven a band of Neanderthals to cannibalism

(credit: Photograph by ORNL)

A new study suggests that a group of Neanderthals in southeast France resorted to cannibalism to survive lean times. If that says anything about Neanderthals, it’s that they weren’t so different from us—for better and for worse.

The bones in the cave

Something awful happened in Moula-Guercy cave in southeastern France around 120,000 years ago. Archaeologists excavating the site in the early 1990s found the bones of six Neanderthals near the eastern wall of the cave, disarticulated and mingled with bones from deer and other wildlife. That mixing of bones, as though the dead Neanderthals had been discarded with the remains of their food, is strange enough; there’s plenty of evidence that Neanderthals typically buried their dead. But at Moula-Guercy, at least six Neanderthals—two adults, two teenagers, and two children—received very different treatment. Their bones and those of the deer show nearly-identical marks of cutting, scraping, and cracking, the kind of damage usually associated with butchering.

“When numerous human remains are discovered on an undisturbed living floor, with similar patterns of damage, mixed with animal remains, stone tools, and fireplaces, they can legitimately interpreted as evidence of cannibalism,” wrote Alban Defleur and Emmanuel Desclaux in a recent paper in the Journal of Archaeological Science.

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Posted in ancient people did stuff, Archaeology, biological archaeology, cannibalism, forensic archaeology, hominins, interglacial, Neanderthals, paleoanthropology, science | Comments (0)

Neanderthal teeth reveal lead exposure and difficult winters

October 31st, 2018
Neanderthal teeth reveal lead exposure and difficult winters

Enlarge

A new study of oxygen isotope ratios and heavy metals in the tooth enamel of Neanderthals who lived and died 250,000 years ago in southeast France suggests that they endured colder winters and more pronounced differences between seasons than the region’s modern residents. The two Neanderthals in the study also experienced lead exposure during their early years, making them the earliest known instances of this exposure.

Enduring harsh winters

Tooth enamel forms in thin layers, and those layers record the chemical traces of a person’s early life—from climate to nutrition to chemical exposures—a little like tree rings on a much smaller scale. Archaeologist Tanya Smith of Griffith University and her colleagues examined microscopic samples of tooth enamel from two Neanderthal children from the Payre site in southeastern France. The teeth were radiocarbon dated to around 250,000 years ago, and the set of samples recorded about three years of life.

One important clue to past environments is oxygen, which comes from the water a person drank or the plants they ate. The ratio of the oxygen-18 isotope to oxygen-16 depends on temperature, precipitation, and evaporation. Generally, higher ratios of oxygen-18 indicate warmer, drier conditions with more evaporation.

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Posted in Archaeology, biological archaeology, isotope analysis, Neanderthals, paleoanthropology, paleoclimate, science, teeth | Comments (0)

Archaeologists find 300,000-year-old stone tools in Saudi Arabia

October 29th, 2018
Archaeologists find 300,000-year-old stone tools in Saudi Arabia

Enlarge (credit: Roberts et al. 2018)

Stone tools unearthed in Saudi Arabia’s inhospitable Nefud Desert indicate that members of our genus Homo had ventured beyond the familiar borders of Africa and the Levant sometime between 300,000 and 500,000 years ago. And according to climate data captured in the bones of animals found at the site, the environment they moved into may not have been that different from the one they left behind in East Africa. That may help anthropologists better understand the role of environment—and the ability to adapt to challenging new landscapes—in shaping human evolution and global expansion.

The things they left behind

Archaeologist Patrick Roberts of the Max Planck Institute for the Science of Human History and his colleagues recently discovered a handful of stone tools in a sandy layer of soil beneath the dry traces of a shallow Pleistocene lake at Ti’s al Ghadah, in the Nefud Desert of northern Saudi Arabia. The soil layer dated to between 300,000 and 500,000 years ago, and it also contained fossilized remains of grazing animals, water birds, and predators like hyena and jaguar. Many of the bones seem to bear the marks of butchering by tool-wielding hominins.

Archaeologists had found other fossils at the site with possible cut marks, but, without stone tools, it’s difficult to determine if a notch in a fossil rib was put there by a human hand and not another predator or natural process. The tools—six sharp brown chert flakes and a scraper—make a much clearer case. Roberts and his colleagues say they’re the oldest radiometrically dated hominin artifacts in the Arabian Peninsula, edging out the previous contender by 100,000 years.

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Posted in anthropology, arabian peninsula, Archaeology, fossil record, homo erectus, human ancestors, human migration, out of africa, paleoanthropology, paleoclimate, paleoecology, Saudi Arabia, science, Stable isotope, stone tools | Comments (0)

Ancient skull found among debris in burned Brazilian museum

October 25th, 2018
Ancient skull found among debris in burned Brazilian museum

Enlarge (credit: Gian Cornachini via Wikimedia Commons)

Archaeologists are celebrating the recovery of an 11,500-year-old skull from the burned rubble of the National Museum of Brazil following a devastating fire on September 2. The skull belongs to a woman, now nicknamed Luzia, who died in a cave in southeastern Brazil early in the history of the settling of the Americas. Archaeologists in the 1970s unearthed about a third of her skeleton, including her remarkably well-preserved skull, her pelvis and lower spine, part of her right femur (the large bone of the upper leg), her left tibia (the shin bone), and left radius (one of the bones of the forearm).

An early American

According to radiocarbon dating done in 2013, Luzia died sometime between 11,243 and 11,710 years ago, which places her bones among the oldest evidence we have of the early population of the Americas. When archaeologists retrieved the charred, cracked pieces of skull and femur from the remains of the museum’s first floor earlier this week, they salvaged a rare and vital source of information about how humans spread through the Americas.

Although archaeologists also found flint tools at the site, Luzia herself had been left alone in the cave with no other human remains nearby. That suggests an unexpected death, perhaps in an accident or an encounter with large Pleistocene wildlife. And at just under 1.5 m (5 ft) tall, Luzia certainly wouldn’t have been much of a match for a saber-toothed cat.

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Posted in 3d scanning, ancient DNA, Archaeology, biological archaeology, museums, paleoanthropology, paleogenomics, peopling of the americas, pleistocene, science, South America, South American archaeology | Comments (0)