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520-million-year-old larva fossil reveals the origins of arthropods

11 August 2024 at 11:30
Image of a small grey object, curved around its abdomen, with a series of small appendages on the bottom.

Enlarge / The fossil in question, oriented with its head to the left. (credit: Yang Jie / Zhang Xiguang)

Around half a billion years ago, in what is now the Yunnan Province of China, a tiny larva was trapped in mud. Hundreds of millions of years later, after the mud had long since become the black shales of the Yuan’shan formation, the larva surfaced again, a meticulously preserved time capsule that would unearth more about the evolution of arthropods.

Youti yuanshi is barely visible to the naked eye. Roughly the size of a poppy seed, it is preserved so well that its exoskeleton is almost completely intact, and even the outlines of what were once its internal organs can be seen through the lens of a microscope. Durham University researchers who examined it were able to see features of both ancient and modern arthropods. Some of these features told them how the simpler, more wormlike ancestors of living arthropods evolved into more complex organisms.

The research team also found that Y. yuanshi, which existed during the Cambrian Explosion (when most of the main animal groups started to appear on the fossil record), has certain features in common with extant arthropods, such as crabs, velvet worms, and tardigrades. “The deep evolutionary position of Youti yuanshi… illuminat[es] the internal anatomical changes that propelled the rise and diversification of [arthropods],” they said in a study recently published in Nature.

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“Archeology” on the ISS helps identify what astronauts really need

9 August 2024 at 17:10
I woman holds a handheld device in front of a rack of equipment.

Enlarge / Jessica Watkins gets to work on the ISS (credit: NASA)

“Archeology really is a perspective on material culture we use as evidence to understand how humans adapt to their environment, to the situations they are in, and to each other. There is no place, no time that is out of bounds,” says Justin Walsh, an archeologist at Chapman University who led the first off-world archeological study on board the ISS.

Walsh’s and his team wanted to understand, document, and preserve the heritage of the astronaut culture at one of the first permanent space habitats. “There is this notion about astronauts that they are high achievers, highly intelligent, and highly trained, that they are not like you and me. What we learned is that they are just people, and they want the comforts of home,” Walsh says.

Disposable cameras and garbage

“In 2008, my student in an archeology class raised her hand and said, ‘What about stuff in space, is that heritage?’ I said, ‘Oh my God, I’ve never thought of this before, but yes,’” Walsh says. “Think of Tranquility base—it’s an archeological site. You could go back there, and you could reconstruct not only the specific activities of Neil Armstrong and Buzz Aldrin, but you could understand the engineering culture, the political culture, etc. of the society that created that equipment, sent it to the Moon, and left it there.”

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Egalitarian oddity found in the Neolithic

6 July 2024 at 11:18
Greyscale image of an adult skeleton in a fetal position, framed by vertical rocks.

Enlarge / A skeleton found during 1950's excavations at the Barman site. (credit: Université de Genève)

Did ancient people practice equality? While stereotypes may suggest otherwise, the remains of one Neolithic society reveal evidence that both men and women, as well as locals and foreigners, were all equal in at least a critical aspect of life: what they ate.

The Neolithic saw the dawn of agriculture and animal husbandry some 6,000 years ago. In what is now Valais, Switzerland, the type and amount of food people ate was the same regardless of sex or where they had come from. Researchers led by Déborah Rosselet-Christ of the University of Geneva (UNIGE) learned this by analyzing isotopes in the bones and teeth of adults buried in what is now called the Barmaz necropolis. Based on the 49 individuals studied, people at the Barmaz site enjoyed dietary equality.

“Unlike other similar studies of Neolithic burials, the Barmaz population appears to have drawn its protein resources from a similar environment, with the same access to resources for adults, whether male or female,” the researchers said in a study recently published in the Journal of Archaeological Science: Reports.

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High-altitude cave used by Tibetan Buddhists yields a Denisovan fossil

3 July 2024 at 18:27
Image of a sheer cliff face with a narrow path leading to a cave opening.

Enlarge / The Baishiya Karst Cave, where the recently analyzed samples were obtained. (credit: Dongju Zhang’s group (Lanzhou University))

For well over a century, we had the opportunity to study Neanderthals—their bones, the items they left behind, their distribution across Eurasia. So, when we finally obtained the sequence of their genome and discovered that we share a genetic legacy with them, it was easy to place the discoveries into context. By contrast, we had no idea Denisovans existed until sequencing DNA from a small finger bone revealed that yet another relative of modern humans had roamed Asia in the recent past.

Since then, we've learned little more. The frequency of their DNA in modern human populations suggests that they were likely concentrated in East Asia. But we've only discovered fragments of bone and a few teeth since then, so we can't even make very informed guesses as to what they might have looked like. On Wednesday, an international group of researchers described finds from a cave on the Tibetan Plateau that had been occupied by Denisovans, which tell us a bit more about these relatives: what they ate. And that appears to be anything they could get their hands on.

The Baishiya Karst Cave

The finds come from a site called the Baishiya Karst Cave, which is perched on a cliff on the northeast of the Tibetan Plateau. It's located at a high altitude (over 3,000 meters or nearly 11,000 feet) but borders a high open plain, as you can see in the picture below.

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Bizarre armor from Mycenaean Greece turns out to have been effective

30 May 2024 at 10:55
Two images of a person wearing unusual armor that covers his torso in bands of metal, with a deep collar and high helmet.

Enlarge / Armor based on the Dendra artifact being tested. (credit: Andreas Flouris and Stavros Petmezas)

The Dendra armor, one of the oldest suits of bronze armor ever found, had been considered a purely ceremonial piece. It seemed impossible to use in battle due to its cumbersome design.

It took over a decade of research, elaborate numerical models, and 13 Greek marines fighting in it from dawn till dusk to prove it was surprisingly good at its job, despite its odd appearance. “This made the Mycenaean warriors some of the best equipped in the Eastern Mediterranean in the Late Bronze Age,” says professor Andreas Flouris, a researcher at the University of Thessaly, who led the study.

Mycenaean Conquests

“The Mycenaeans were an ancient Greek civilization that flourished during the late Bronze Age, roughly from 1600 BC to 1100 BC,” explains Ken Wardle, an archeologist at the University of Birmingham and co-author of the study. With their power centered around major cities like Mycenae, Thebes, Tiryns, and Pylos, the Mycenaeans peaked between 1400 BCE and 1200 BCE, when they occupied much of mainland Greece and gained influence over Aegean islands and Asia Minor.

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