Human evolution; hominins late in Arabia (Introduction)

by David Turell , Tuesday, December 04, 2018, 18:01 (1969 days ago) @ dhw

New stone tool findings:

https://www.livescience.com/64203-ancient-hominins-saudi-arabia.html?utm_source=lsa-new...

"Ancient human relatives lived on the Arabian Peninsula for an astonishingly long time — from about 240,000 to 190,000 years ago — and spread into the heart of the region by following its blue rivers and lakes, a new study found.

"These early human relatives persisted for so long that they could have run into some modern humans, or Homo sapiens, along the way, the researchers said in the study,

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"'Early hominins had small brains and made crude tools," Scerri told Live Science. "However, later hominins had bigger brains and were more sophisticated. Instead of crudely banging rocks together to produce sharp-edged stone flakes, they created beautiful, symmetrical artifacts called hand axes."

"Large, expertly shaped cutting tools (such as hand axes) made by hominins are known as Acheulean tools. These instruments — called the "the Swiss army knife of prehistory" — date to 1.5 million years ago; they come from the longest-lasting tool-making tradition in prehistory, Scerri said. Because it's rare to find hominin bones, Acheulean tools are a great stand-in for hominins when trying to figure out when and where they lived, the researchers said.

"It's unclear which hominins made the hand axes in Saudi Arabia. "However, hominins that have been found with Acheulean tools include Homo erectus, who was probably a direct ancestor of humans," Scerri said.

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"The dating revealed that hominins lived in Saffaqah as recently as 188,000 years ago, making it the youngest Acheulean site in southwest Asia, the researchers found. This finding is remarkable, because it shows that the Arabian Acheulean ended just before or at the same time as the earliest H. sapiens made it to the region, the researchers said.

"The international team used luminescence dating to determine the age of the tools. This method measures how much light is emitted from energy stored in certain types of rock and soils, as certain minerals store energy from the sun at a known rate, Scerri said.

"When these minerals are buried, they can no longer store this energy," she said. "By heating the minerals, the stored energy becomes emptied, and the amount of energy that is emptied gives a measure of a point in time when that mineral was last exposed to daylight."

"The research also revealed that these hominins spread throughout Saudi Arabia's landscape via its blue waterways. Although Arabia is a vast desert today, it was greener during several brief periods in the past.

"'The hominins making the Acheulean tools at Saffaqah seemed to have made their way into the heart of Arabia when these now-dry river networks and channels were active," Scerri said.

"But Saudi Arabia was turning dry again by about 188,000 years ago, she said. So, it's likely that "the hominins responsible for these stone tools were quite resilient in the face of environmental challenges," she said. "Although the site of Saffaqah was not a desert when these Acheulean hominins were there, it was probably still quite an arid environment.'"

Comment: Disappearance of a hominin type is not like turning off a light bulb. They die off slowly. That H. sapiens and H. erectus lived side by side suggests sapiens appeared with no intermediate forms. H. sapiens by direct creation is possible.