Human evolution: new Paranthropus robustus skull find (Introduction)

by David Turell , Monday, November 09, 2020, 23:09 (1473 days ago) @ David Turell

A very early hominin, two million years old:

https://cosmosmagazine.com/nature/evolution/well-preserved-addition-to-the-evolution-st...

"A two-million-year-old hominin skull has been uncovered in a South African cave, providing fresh insight into the microevolution of our ancient cousins.

"The skull is the earliest-known and best-preserved specimen of Paranthropus robustus: a short, robust, upright hominin that is thought to have gone extinct around a million years ago. The species possessed distinctive large molars and powerful jaws that would have been useful for eating tough vegetation, seeds and roots.

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“'The DNH 155 cranium shows the beginning of a very successful lineage that existed in South Africa for a million years,” says La Trobe’s Andy Herries, a co-author.

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"Since their discovery in 1992, the Drimolen caves have acted as a window into early hominin evolution. In 2018 they revealed some of the world’s oldest bone tools, and earlier in 2020, a research team led by Herries uncovered the earliest-known skull of Homo erectus, a much closer relative of modern humans.

"The species existed from around two million to 100,000 years ago, arising at around the same time as Paranthropus robustus. The Drimolen caves also previously yielded several other P. robustus skulls, providing evidence for their co-existence with H. erectus.

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"But the two species were vastly different. While H. erectus had relatively large brains and small teeth, P. robustus were small-brained and large-toothed. According to co-author Angeline Leece, also from La Trobe, the two represent “divergent evolutionary experiments”.

"This new study presents another P. robustus cranium – dubbed DNH 155 – that dates back further, to approximately 2.04-1.95 million years ago.

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“The DNH 155 male fossil from Drimolen is most similar to female specimens from the same site, whereas Paranthropus robustus specimens from other sites are appreciably different,” he says.

"The specimen also suggests that the species evolved their distinctive chewing adaptations in incremental steps over hundreds of thousands of years, leading the team to argue that this is the first high-resolution evidence of microevolution in an early hominin species.

"Leece explains that, over time, “Paranthropus robustus likely evolved to generate and withstand higher forces produced during biting and chewing food that was hard or mechanically challenging to process with their jaws and teeth – such as tubers.”

"These adaptations are believed to have taken place during a period of environmental change, when climate records indicate that the region was drying out. The increasingly arid conditions led to the extinction of several mammal species and may have placed hominins under dietary stress."

Comment: This adds to the story and tells us that many different types of hominins coexisted, as more advanced forms developed, and also notes the forms modified as needs changed. Was this epigenetics in action, but not speciation. since it appears within the same species?