Saturday, November 14, 2020

An Extinct Human Species

 From SciTechDaily:

Males of the extinct human species Paranthropus robustus were thought to be substantially larger than females — much like the size differences seen in modern-day primates such as gorillas, orangutans and baboons. But a new fossil discovery in South Africa instead suggests that P. robustus evolved rapidly during a turbulent period of local climate change about 2 million years ago, resulting in anatomical changes that previously were attributed to sex.

An international research team including anthropologists at Washington University in St. Louis reported their discovery from the fossil-rich Drimolen cave system northwest of Johannesburg in the journal Nature Ecology & Evolution today (November 9, 2020).

“This is the type of phenomenon that can be hard to document in the fossil record, especially with respect to early human evolution,” said David Strait, professor of biological anthropology in Arts & Sciences at Washington University.

The remarkably well-preserved fossil described in the paper was discovered by a student, Samantha Good, who participated in the Drimolen Cave Field School co-led by Strait.

Researchers already knew that the appearance of P. robustus in South Africa roughly coincided with the disappearance of Australopithecus, a somewhat more primitive early human, and the emergence in the region of early representatives of Homo, the genus to which modern people belong. This transition took place very rapidly, perhaps within only a few tens of thousands of years.

“The working hypothesis has been that climate change created stress in populations of Australopithecus leading eventually to their demise, but that environmental conditions were more favorable for Homo and Paranthropus, who may have dispersed into the region from elsewhere,” Strait said. “We now see that environmental conditions were probably stressful for Paranthropus as well, and that they needed to adapt to survive.” (Read more.)
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