在 8 公尺深的坑中發現的骨頭可能會「從根本上改變」歐洲人類的歷史 (2/2)

Recently Yahoo News on-line reported the following:

Bones found in 8-meter-deep pit may ‘fundamentally change’ history of humans in Europe (2/2)

Katie Hunt, CNN

Thu, February 1, 2024 at 12:53 p.m. PST·5 min read

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However, the human remains weren’t immediately identifiable among the hundreds of bone fragments unearthed during the six-year dig. It was only later the team knew definitively that the layers of sediment that contained the LRJ stone tools also included humans remains.

The researchers used proteins extracted from bone fragments to identify animal and human remains they found, a technique known as palaeoproteomics. It allows scientists to identify human and animal bones when their form is unclear or uncertain. Using the same technique, the team also managed to identify human remains among bones excavated during the 1930s.

However, the protein analysis was only able to identify the bones as belonging to hominins — a category that includes Homo sapiens and Homo neanderthalensis, or Neanderthals. To distinguish between the two, the team was able to extract fragments of ancient DNA from the 13 human fossils they identified.

“We confirmed that the skeletal fragments belonged to Homo sapiens,” said study coauthor Elena Zavala, a postdoctoral research fellow at the University of California, Berkeley, and Max Planck Institute for Evolutionary Anthropology, in the release.

“Interestingly, several fragments shared the same mitochondrial DNA sequences — even fragments from different excavations,” Zavala added. “This indicates that the fragments belonged to the same individual or were maternal relatives, linking these new finds with the ones from decades ago.”

Unexpected adaptability

Radiocarbon dating of the fossils and other artifacts in the cave suggested that these early humans were living there from around 45,000 years ago, making them the earliest Homo sapiens known to have inhabited northwestern Europe.

The region would have had a dramatically different climate then, with conditions typical of steppe tundra such as that found in present-day Siberia. The dig revealed the presence of reindeer, cave bears, woolly rhinoceroses and horses. The researchers also concluded that hibernating cave bears and denning hyenas primarily used the cave, which had only periodic human presence.

“This shows that even these earlier groups of Homo sapiens dispersing across Eurasia already had some capacity to adapt to such harsh climatic conditions,” said coauthor Sarah Pederzani, a postdoctoral fellow at the University of La Laguna in Spain, who led the paleoclimate study of the site. “Until recently, it was thought that resilience to cold-climate conditions did not appear until several thousand years later, so this is a fascinating and surprising result,” she said, according to the news release.

William E. Banks, a researcher at the University of Bordeaux in France, said the studies showed how new methods are allowing archaeologists to examine sites in unprecedented detail, improving the ability to pinpoint when a site was occupied.

The “discoveries provide another important piece of the puzzle of this culturally and demographically complex period in Europe,” Banks noted in a commentary published alongside the studies. However, Banks, who wasn’t involved in the research, added that archaeologists “must be careful not to generalize findings from one or two sites.”

He noted that recent discoveries suggested Neanderthals were more culturally and cognitively complex than popular stereotypes suggest and that archaeologists should “not necessarily assume” in all cases that modern humans made more complex styles of stone tools from that pivotal period before Neanderthals disappeared.

Translation

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然而，在為期六年的挖掘過程中出土的數百塊骨頭碎片中，無法立即辨認出人類遺骸。 直到後來，研究團隊才明確知道，含有 LRJ 石器的沉積物層還包括人類遺骸。

研究人員利用從骨頭碎片中提取的蛋白質來識別他們發現的動物和人類遺骸，這種技術被稱為古蛋白質組學。 當人類和動物的骨骼形狀不清楚或不確定時，它使科學家能夠識別它們。 使用相同的技術，該團隊還成功地在 20 世紀 30 年代挖掘的骨頭中識別出人類遺骸。

然而，蛋白質分析只能辨識出這些骨頭屬於別包括智人的古人類和尼安德塔人，或稱為尼人。 為了區分兩者，研究小組成功從他們鑑定的 13 塊人類化石中提取了古代 DNA 碎段。

研究合著者、加州大學柏克萊分校和 Max Planck 進化人類學研究所的博士後研究員 Elena Zavala 在新聞稿中說: 「我們證實這些骨骼碎片屬於智人」。

Zavala 補充道: 「有趣的是，幾個碎段共享相同的粒線體 DNA 序列 - 甚至是來自不同發掘的碎段」。 「這表明這些碎段屬於同一個人或者是母系親屬，這些新發現聯繫起幾到幾十年前的碎段」。

意想不到的適應性

對洞穴中的化石和其他文物進行的放射性碳測年表明，這些早期人類在大約 45,000 年前就生活在那裡，使他們成為已知居住在歐洲西北部的最早的智人。

那時該地區有截然不同的氣候，具有典型的草原苔原條件，例如今天的西伯利亞。 挖掘工作發現了馴鹿、洞熊、披毛犀和馬的存在。 研究人員也得出結論，冬眠的洞熊和穴居鬣狗主要使用這個洞穴，而那裡只有週期性的人類出現。

共同作者、並領導了這掘挖關於古氣候研究的西班牙 La Laguna 大學的博士後研究員 Sarah Pederzani說: 「這表明，即使是這些分佈在歐亞大陸的早期智人群體也已經具備了一定的能力來適應如此惡劣的氣候條件」。 據新聞稿稱她說: 「直到最近，人們還認為對寒冷氣候條件的適應能力要到幾千年後才出現，所以這是一個令人著迷及驚訝的結果」。

法國 Bordeaux 大學的研究員 William E. Banks 表示，這些研究表明，新方法如何讓考古學家能夠以前所未有的細節檢查遺址，從而提高查明遺址何時被佔用的能力。

Banks 在與這些研究一起發表的評論中指出，「這些發現為歐洲這個文化和人口複雜時期的拼圖提供了一個重要的部份拼圖」。 然而，沒有參與這項研究的 Banks 補充說，考古學家 “必須小心，不要將一兩個遺址的發現泛化出去。”

他指出，最近的發現表明，尼安德塔人在文化和認知上比普遍化的定型更加複雜，考古學家「不一定要假設」在所有情況之下，現代人類在尼安德塔人消失之前的那個關鍵時期已製造了更複雜的石器。

       So, microscopic fragments of protein and DNA recovered from bones discovered in 8-meter-deep cave dirt revealed Neanderthals and humans had likely lived alongside one another in northern Europe as far back as 45,000 years ago. Yet some archaeologists have pointed out that we must be careful not to over generalize findings from one or two sites to say that all cases would be the same.

Note:

During the Last Glacial Maximum, the mammoth steppe, also known as steppe-tundra (草原苔原), was once the Earth's most extensive biome. It stretched east-to-west, from the Iberian Peninsula in the west of Europe, across Eurasia to North America, through Beringia (what is today Alaska) and Canada; from north-to-south, the steppe reached from the arctic islands southward to China. The mammoth steppe was cold and dry, and relatively featureless, though topography and geography varied considerably throughout. The steppe is known to be flat and expansive grassland. The vegetation is dominated by palatable, high-productivity grasses, herbs and willow shrubs. (Wikipedia)