Part of the Amazon Thought to Be Uninhabited May Have Been Home to 1 Million People

Aerial photo of site Mt05, a circular enclosure (140 meter diameter) located on a hilltop.
Aerial photo of site Mt05, a circular enclosure (140 meter diameter) located on a hilltop.
José Iriarte

Depictions of the pre-Columbian Amazon basin as dense, inhospitable jungle with just a handful of indigenous communities scattered along the river may need to be updated. According to research published in Nature Communications, there were millions more people living in the rainforest prior to Spanish colonization than previously believed.

The Amazon is the largest rainforest on Earth, which poses a challenge to archaeologists exploring the history of the people who lived there. It's long been assumed that native Amazonians chose to avoid the heart of the forest and instead lived as nomads, never straying far from the major rivers. Some old estimates placed the population of the entire basin between 1.5 and 2 million people.

Thanks to satellites, researchers can now identify traces of long-gone settlements in the less-explored regions of Brazil without having to set foot in the jungle. A team of archaeologists from the University of Exeter used satellite imaging to find geoglyphs—large shapes dug into the ground, possibly for ceremonial purposes—in part of the Brazilian state of Mato Grosso that was thought to be uninhabited.

Geoglyphs and mounded ring villages.
Geoglyphs and mounded ring villages.
Nature Communications, Jonas Gregorio de Souza et al.

After pinpointing the locations of these earthworks, archaeologists visited this section of the southern rim of the Amazon to see some of them in person. At each of the 24 sites they set out to confirm, they found a real-life geoglyph on the ground. At one location, they uncovered charcoal and pottery dating back to 1410 CE. In all, they documented 81 new sites with geoglyphs.

The earthworks would have been carved into the dirt during a seasonal drought, allowing the architects to clear a swath of rainforest. Fortified villages were built in or close to the glyphs, with a network of roads connecting them to each other. The researchers created a computer model that estimated that a 154,000-square-mile patch of land could be home to the remains of 1300 geoglyphs and villages, only two-thirds of which have been discovered. In the late pre-Columbian period, the area, comprising just 7 percent of the Amazon basin, may have sustained a population of 500,000 to 1 million people, according to the researchers' models.

Aerial photo of site ZMt04, which contains the two largest enclosures that were identified.
Aerial photo of site ZMt04, which contains the two largest enclosures that were identified.
José Iriarte

Disease and genocide brought on by the European invasion destroyed most of those settlements, and they were later reclaimed by the rainforest. But evidence of their existence suggests that deforestation and development of the Amazon isn't a new phenomenon.

"Our research shows we need to re-evaluate the history of the Amazon. It certainly wasn't an area populated only near the banks of large rivers, and the people who lived there did change the landscape," researcher José Iriarte said in a statement. "Studies such as ours mean we are gradually piecing together more and more information about the history of the largest rainforest on the planet."

Scientists Find Fossil of 150-Million-Year-Old Flesh-Eating Fish—Plus a Few of Its Prey

M. Ebert and T. Nohl
M. Ebert and T. Nohl

A fossil of an unusual piranha-like fish from the Late Jurassic period has been unearthed by scientists in southern Germany, Australian news outlet the ABC reports. Even more remarkable than the fossil’s age—150 million years old—is the fact that the limestone deposit also contains some of the fish’s victims.

Fish with chunks missing from their fins were found near the predator fish, which has been named Piranhamesodon pinnatomus. Aside from the predator’s razor-sharp teeth, though, it doesn’t look like your usual flesh-eating fish. It belonged to an extinct order of bony fish that lived at the time of the dinosaurs, and until now, scientists didn’t realize there was a species of bony fish that tore into its prey in such a way. This makes it the first flesh-eating bony fish on record, long predating the piranha. 

“Fish as we know them, bony fishes, just did not bite flesh of other fishes at that time,” Dr. Martina Kölbl-Ebert, the paleontologist who found the fish with her husband, Martin Ebert, said in a statement. “Sharks have been able to bite out chunks of flesh, but throughout history bony fishes have either fed on invertebrates or largely swallowed their prey whole. Biting chunks of flesh or fins was something that came much later."

Kölbl-Ebert, the director of the Jura Museum in Eichstätt, Germany, says she was stunned to see the bony fish’s sharp teeth, comparing it to “finding a sheep with a snarl like a wolf.” This cunning disguise made the fish a fearful predator, and scientists believe the fish may have “exploited aggressive mimicry” to ambush unsuspecting fish.

The fossil was discovered in 2016 in southern Germany, but the find has only recently been described in the journal Current Biology. It was found at a quarry where other fossils, like those of the Archaeopteryx dinosaur, have been unearthed in the past.

[h/t the ABC]

Advanced CT Scans Reveal Blood Vessels and Skin Layers in a Mummy's Hand

Jenny Romell, et al./Radiology
Jenny Romell, et al./Radiology

Mummies hold some intriguing secrets to their pasts, like the food they ate and the diseases they had when they were alive. Now scientists are using a tool originally designed for medicine to get an even deeper look at the clues mummified bodies carry with them into the present day, Gizmodo reports.

In a proof-of-concept study published in the journal Radiology, researchers from the KTH Royal Institute of Technology in Sweden detail how a new-and-improved CT scanning technique can be used to visualize the interior of mummies on a microscopic level. By creating detailed X-ray images, CT scans allow doctors to see inside their patients without invasive surgery. Archaeologists have been using this technology to study delicate ancient artifacts for years, but the level of detail that can be achieved this way—especially when it comes to looking at interior soft tissue—is limited.

The upgraded version of the tech, called phase-contrast CT scanning, measures the phase shift, or the change in the position of a light wave, that occurs when X-rays pass through solid objects. The images generated this way have a higher contrast level than conventional X-rays, which means they capture more detail.

Cross-section of mummy hand.
Jenny Romell, et al./Radiology

Doctors have been using this 10-year-old technology to examine soft tissues like organs and veins in living patients, but it hadn't been used on a mummy until recently. Working with a mummified human right hand dating back to 400 BCE in Egypt, which they borrowed from the Museum of Mediterranean and Near Eastern Antiquities in Stockholm, the researchers fired up a phase-contrast CT scanner. It produced images with a resolution of 6 to 9 microns, giving a clear picture of the different layers of skin, individual cells in the connective tissue, and the blood vessels in the nail bed—all without damaging the artifact. Previously, researchers looking to study these same tissues in mummies would have needed to use a scalpel.

As Ars Technica reports, a phase-contrast CT scanner is similar in cost to the conventional machine. The study authors hope their work will lead to phase-contrast CT scanning becoming just as common in archaeology as regular CT scanning, potentially creating new research opportunities in mummies that will be discovered in the future and even in artifacts that have already been examined.

[h/t Gizmodo]

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