Since the last article was about how we (homo sapien) weren't responsible for the demise of the Neanderthal's after all...,I might as well continue the story with this exploration of our recent and distant past!
A 1.5 million-year-old vertebra from an extinct human species unearthed in Israel suggests that ancient humans may have migrated from Africa in multiple waves instead of just once, a new study finds.
Although modern humans, Homo sapiens, are now the only surviving members of the human family tree, other human species once roamed Earth. Prior work revealed that long before modern humans made their way out of Africa as early as about 270,000 years ago, now-extinct human species had already migrated from Africa to Eurasia by at least 1.8 million years ago, during the early parts of the Pleistocene (2.6 million to 11,700 years ago), the epoch that included the last ice age.
Scientists had debated whether ancient humans dispersed from Africa in a one-time event or in multiple waves. Now, researchers have discovered the latter scenario is more likely, based on a newly analyzed vertebra from an unknown human species. At about 1.5 million years old, the vertebra is the oldest evidence yet of ancient humans in Israel, study lead author Alon Barash, a paleoanthropologist and human anatomist at Bar-Ilan University in Israel, told Live Science.
The bone was discovered in the prehistoric site of 'Ubeidiya in the Jordan Valley, the second-oldest archaeological site outside Africa. The site includes not only ancient stone artifacts resembling those found at sites in East Africa but also a rich collection of animal bones belonging to extinct species such as saber-toothed cats and mammoths.
In 2018, after reexamining bones initially unearthed in 'Ubeidiya in 1966, the scientists discovered what appeared to be a vertebra from the lower back of a hominin, the group that includes humans, our ancestors and our closest evolutionary relatives.
"It's great to see new discoveries coming from old collections like this one," John Hawks, a paleoanthropologist at the University of Wisconsin-Madison who was not involved with the study, told Live Science. "It shows that there is always something left to find even when archaeologists think they've done it all."
After the researchers compared the vertebra with those from a range of animals — such as bears, hyenas, hippos, rhinos, horses, gorillas and chimps — that once lived in the 'Ubeidiya region, the team concluded that the bone came from an extinct species of human. (There is not enough data from this one bone to reveal whether it belonged to any known species of extinct human.)
Based on the bone's size, shape and other features, the researchers estimated it belonged to a 6- to 12-year-old child. However, they estimated that at death, the child would have stood about 5 feet, 1 inch (155 centimeters) and weighed about 100 to 110 pounds (45 to 50 kilograms) — as large as an 11- to 15-year-old modern human. In other words, this child would have been head and shoulders taller than its modern counterparts.
"The study shows how much information about an ancient individual we can get from a small piece of the anatomy," Hawks said.
Roughly 1.8 million-year-old human fossils previously unearthed in Dmanisi, Georgia, suggested those extinct humans were small-bodied hominins about 4 feet, 9 inches to 5 feet, 5 inches (145 to 166 cm) in height and 88 to 110 pounds (40 to 50 kg) in weight as adults. In contrast, scientists analyzing the 'Ubeidiya vertebra suggested that in adulthood, that person might have reached even greater heights: 6 feet, 6 inches (198 cm) and 220 pounds (100 kg).
"Dmanisi hominins are small in body size — at the smallest end of human variation across populations today," Hawks said. "This new vertebral body suggests a large body size, like some of those seen in Africa at around the same time.
These findings indicate that the 1.8 million-year-old fossils previously found in Dmanisi and the 1.5 million-year-old fossil in 'Ubeidiya belonged to two different kinds of hominins. As such, ancient humans likely departed Africa in more than one wave, the researchers said.
