Earth Science In the News: Rock Record and Ancestry

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This skull face of a Paranthropus robustus, which was discovered in South Africa. It resides in the Transvaal Museum in South Africa. JOSÉ BRAGA;DIDIER DESCOUENS,

By Jim Brace-Thompson

 

Reports have been all over the news in recent months regarding humans from way back when. For instance, hundreds of human footprints have been unearthed in Tanzania, recording ancient ancestors who walked across a mudflow 10,000 to 12,000 years ago. It is said to be the largest collection of ancient human footprints ever discovered in Africa, with the number of prints adding up to more than 400, per a report in the journal Scientific Reports. 

 

Another report details a cave south of Lisbon, Portugal, called Figueira Brava. This report delves deeper into time to transport us into the daily lives of our Neanderthal cousins some 86,000 to 106,000 years ago. It turns out that our ancient evolutionary cousins enjoyed surf-and-turf just as much as we do today. "Menu items" found in the cave include eel spines, seals, limpets, mussels, and sharks, as well as deer, horse, aurochs (ancient cows), ibex (sheep), and—for the vegans among us—pine nuts.

 

Finally, it appears that way back when we were not alone. While nowadays, Homo sapiens is the last and only representative on our human family tree, if we transport ourselves back some 1.8 to 2.3 million years, we would have found ourselves as just one of at least three contemporaneous species. 

 

Per a recent report in the journal Science, South Africa was home to some three hominid species at the same time, including Australopithecus, Paranthropus, and Homo erectus. This conclusion took some time to derive due to difficulties in dating bones and artifacts from South African caves. A recent study used a combination of uranium-lead dating of sediments, uranium-series electron spin resonance analysis of teeth and bones, and paleomagnetism records from volcanic sediments.  

 

All such methods are above my pay grade, so I'll take the paleontologists at their word!