Skulls and Brains

5 Apr 2020

At https://archaeologynewsnetwork.blogspot.com/2020/04/our-direct-human-anc... ... one suspects this is more about making a name than anything concrete - but I may doing a disservice to the scientists involved as they appear to be extremely clever. The Drimden paleo cave is not a cave but an amphitheatre (a roofless cave) and it contains in the cave sediments lots of remains of animals - and humans. All types of human bone and skull fragments. Some of the skulls have been pieced together and we have a pair of Paranthropus robertus (which were discovered back in 1994). They are just two of 160 fossilised specimens dug up. A paper published in Science this month identifies a succession of direct ancestors, including Homo erectus. This specimen has been dated over 2 million years ago - older than any other fossil of the species yet found. We are told this means that Homo erectus originated in southern Africa and dispersed northwards, reaching the Caucasus (the  previous oldest fossil was found there) within a couple of hundred thousand years. Well, you could walk a lot quicker than that but that is not the point. When it comes to hominins it is all about oldest fossil equals land of origin  and all the publicity and all the kudos etc. Also, we are told the evidence from the cave suggests Homo erectus shared cave space with other hominins - Paranthropus and Australopithecus. This was arrived at by a dating technique that used paleomagnetisim. This assumes earth's magnetic field has changed at a specific rate over time (what can go wrong with such an assumption). This is said to show the three hominin groups were contemporary with each other - or lived at the same point in time (in the landscape if not in the cave). Or is that a false flag as the sediments in the cave must have provided part of the evidence - as well as the skull fragments. The skull fragments were subsequently fitted together and glued in order to get the bigger picture of them. It must have taken a lot of time to achieve this - and no doubt modelling was involved in the jigsaw. Two other dating methodologies were involved (so the date might be an average). These are uranium lead dating and electron spin resonance. However, much later we learn that the Homo erectus skull came from a 2 to 3 year child. Very young. Why am I feeling a trifle sceptical.

At https://phys.org/news/2020-04-oldest-ever-human-genetic-evidence-dispute... ... see the journal Nature at https://doi.org/10.1038/s41586-020-2153-8 ... genetic information extracted from a tooth dated 800,000 years ago of a proto human known as Homo antecessor, found to be related to Neanderthals and Denisovans and living around the same time both of them evolved. Protein from the tooth enamel has been subject to mass spectrometry in order to produce a date and place Homo antecessor on the family tree. The tooth was found in a cave in northern Spain.

At https://phys.org/news/2020-04-skull-scans-reveal-evolutionary-secrets.html ... a new study in Science Advances used CT scanning to view a 3 million year old brain imprint inside a fossil skull (which had been pieced together). It came from an Australopithecus afarensis (Lucy to the media) from the Rift Valley in Ethiopia. It had an ape like brain structure we are told - but there is a caveat. It seems the individual, another child, would take longer to reach adulthood than an ape and therefore must be a sign of a link to humanity (and can be slotted a position on the human tree).

At www.sciencedaily.com/releases/2020/04/200401150821.htm ... this one is getting closer - evidence tha modern humans and Neanderthals interbred on multiple occasions (described as a tangled past as if they were having affairs on the side). People in Eurasia today have genetic material inherited from Neanderthals. Another cave, this time in Croatia, is the scene of the crime. The study was published in the journal Genetics (March 2020) but see https://doi.org/10.1534/genetics.120.303167