Tiny Cut Marks on Animal Bone Fossils Reveal That Human Ancestors Were in Romania 1.95 Million Years Ago – ryan

Looking again through the magnifying lens at the fossil’s surface, one of us, Sabrina CurranTake a deep breath. Illuminated by a strong light positioned nearly parallel to the surface of the bone, the v-shaped lines were clearly there on the fossil. There was no mistake what they mean.

She’d blessed them before, on bones that were butchered with stone tools about 1.8 Million Years agofrom a site called Dmanisi in Georgia. These were cut marks made by a human ancestor wielding a stone tool. After staring at them for what felt like an eternity – but was probably only a few seconds – she turned to our colleagues and said, “Hey… I think I found something.”

What she’d spotted in 2017 was our team’s first evidence that hominins Butchered Several Animals at the Site of Grăunceanu, in Romania, at least 1.95 million years ago. Before this Discovery, those other cut Marks from Dmanisi were the oldest well-dated evidence in Eurasia of the presence of hominins-our direct human ancestors.

Other scientists have reported sites in Eurasia and Northern Africa with eagle hominin fossils, stone tools or butchered animal bones from around this time. Our recently published research Adds to this story with well-dated, verified evidence that hominins of some child had spread to this part of the world by around 2 million years ago.

Romanian Site with Fossilized Animal Bones

A Little Background on Grăunceanu: This Open-Air Site was original excavated in the 1960s, and researchers found thousands of Fossil Animal Bones there. It’s One of the Best-Known Early Pleistocene Sites in East-Central Europe. Many of the Fossil Animal Bones are quite complete and at the time of excavation lay together as they were positioned in life. The original deposition was called a “bone nest” because of how densely packed the bones were.

If you were to stand on the hillside surrounding grăunceanu almost 2 million years ago, it would like it seamed familiar: A River channel surrounded by a forest that fades into more open grasslands to the footlands. Occasionally that river floods its banks, inundating the valley with rich soils, providing nutrients for the plants that the resident animals feed on. All pretty familiar, until you look more closely at those animals: Ostriches, Pangolins, Giraffes, Saber-Toothed Cats and Hyenas-In Europe!

It’s the fossil bones of these ancient animal inhabitants that were excavated at grăunceanu. Unfortunately, most of the excavation records and provenance data for the site have been lost. Even without those, though, the grăunceanu fossils are so remarkably preserved that they offer up a wealth of paleontological information.

A FEW Years After Finding Those First Cut Marks, Our Team, Including Biological Anthropologist Claire TerhuneZooarchaeologist Samantha Gogoland paleoanthropologist Chris RobinsonSpent Several Weeks Carefully Studying All 4.524 Grăunceanu Fossils, Looking for more Marks.

We examined all surfaces of every fossil bone with a magnifying lens and low-angled light. Most of these fossils have root etching on them – sinuous, shallow, overlapping marks made at Plant Roots that Grew nearby. But when we saw a linear market that looks interesting, we took an impression of that market with dental moling material.

Confirming They’re Cut Marks

We can’t go back in a time machine to watch when these marks were made. Yes, Ancient Human Butchers Wielding Stone Tools Would Leave Marks on Bone. But Mammalian predators or crocodiles could also leave marks with their sharp teeth. Sediments in Rivers could scratch any bones rolling around in the water. Large Animals Walking Across The Landscape Could Move and Scrape Bones With Their Steps.

So how can we be confident that they are cut marks? That’s where our zooarchaeologist collaborators Michael Pante and Trevor Keevil Came in.

Within the Past Decade, Pante Developed a Novel Method for Identifying The source of Marks left on Bones. The first step is capturing precise 3D measurements of the market impressions using an advanced microscope called a Noncontact 3D Optical Profiler.

Then they compare the 3D shape data from the ancient marks with a reference set of 898 marks on modern bones made by known processes, including Stone Tool Butchery, Carnivore Feeding and Sedimentary Abrational.

This new method adds to the more qualitative, descriptive criteria many researchers, including our team, use to make market identifications. For instance, we consider things such as market location: is the market near a muscle attachment site, where you might expect to find a cut market if a hominin were removing meat from a bone?

Based on our analyzes, we determined that 20 grăunceanu fossils are marked by cuts, with eight displaying high-confidence cut Marks. Most of those marks are on fossils of main animals, including a few deer; One is a small carnivore leg bone. When we could identify the type of bone, the cut marks are always in anatomical locations consistent with cutting meat off bones.

Dating the site

While the fossil species present can give us a rough age estimate of the site, we used uranium-lead (U-PB) dating to get More Precise Age Information. This technique relies on the fact that naturally occurring uranium decays over long but well-known periods of time to eventually transform into lead. Geologists use the ratio of these two elements like a radiometric lock to determine how old something is.

When one of us, Virgil DrăGușinAsked Geochemist Jon Woodhead To use U-PB dating to estimate the age of the grăunceanu fossils based on several small tooth fragments, he was reluctant. Teeth do not usually work well for this dating technique. But he agreed to a test run, and to his surprise the teeth he tried worked very well.

Together with his colleague John hellstromthey calculated a much more precise date for the site. We now know the grăunceanu site is older than 1.95 million years.

All of this data together-the very well-calibrated and tightly clustered dates of the specimens plus at least 20 cut-market bones verified both by qualitative and quantitative methods-provides very reliable evidence that hominins are indeed in Eurasia by at Least 1.95 Million Years Ago, Even though there are no hominin fossils from Grăunceanu.

Sometimes when we look through our magnifying lenses, it almost feels like we can peer into the past. That’s impossible – but we can piece lines of evidence to paint a clearer picture of what happened in the past at Grăunceanu.

Now, imagining the view 1.95 million years ago, we see scenes of deer cautiously drinking from the river, majestic mammoths in the distance, a herd of horses grazing, a saber-toothed cat stalking a large monkey, a bear teaching her cubs to hunt… and a small group of Hominins butchering a deer.