[Adam Khor]

"Rhodesia man" skull (Homo heidelbergensis) shows no ancestral traits to our species:



https://news.yahoo.com/landmark-skul...150935687.html

wo sophisticated dating methods have determined the skull to be about 299,000 years old, plus or minus 25,000 years, said geochronologist Rainer Grün of Griffith University in Australia, lead author of the study published in the journal Nature. Some experts had hypothesized it was 500,000 years old.

This indicates the species represented by the skull was unlikely to have been a direct ancestor of Homo sapiens as some had thought. Our species first appeared more than 300,000 years ago in Africa, later spreading worldwide.

Scientists initially assigned the skull to a species they called Homo rhodesiensis. Most scientists now assign it to the species Homo heidelbergensis, which inhabited parts of Africa and Europe starting about 600,000 years ago.

The skull, dubbed Rhodesian Man when it was discovered, possesses primitive features such as a large face, flat forehead and huge brow ridges. Its brain size fits in the range of our species.

"It's a surprisingly late age estimate, as a fossil at about 300,000 years might be expected to show intermediate features between Homo heidelbergensis and Homo sapiens, but Broken Hill shows no significant features of our species," said Stringer, a study co-author.

"Also, the latest research suggests that the facial shape of Homo heidelbergensis fossils does not fit an ancestral pattern for our species," Stringer added.

[Adam Khor]

Did early humans boil their food in hot springs?

https://phys.org/news/2020-09-early-...-food-hot.html

[Adam Khor]

New study analyzes the diet of the prehistoric primates from the Turkana Basin fossil sites, and finds that Australopithecus anamensis was apparently a browser, Kenyanthropus fed in more open environments, and the giant monkey Theropithecus brumpti was perhaps more omnivorous (and even, more carnivorous) than previously believed.

The study also touches on Paranthropus' diet and apparent differences between the southern African and eastern African population's diets.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7367883/

[Adam Khor]

Two newly discovered skulls from Drimolen, South Africa, add to the evidence of Paranthropus, Australopithecus and Homo erectus' coexistence 2 million years ago.

https://science.sciencemag.org/conte.../6486/eaaw7293

[Adam Khor]

New, beautifully preserved skull of a Paranthropus robustus, found in South Africa; apparently lived during a time of climate change, in which conditions became drier and cooler. Australopithecus would've dissappeared due to these changes, but Homo and Paranthropus managed to adapt.

https://www.amnh.org/explore/news-bl...apid-evolution

[Adam Khor]

This is sure to be controversial, but here it is; the paper suggests the Atapuerca hominins were hibernating to an extent:

https://www.sciencedirect.com/scienc...03552120300832

[Wibbs]

Interesting indeed. IIRC there's only one example of a primate that can hibernate so I'd be sceptical. Looking at those findings I'd be thinking not of hibernation, but of radical annual dietary shifts because of sudden environmental change for which they'd not adapted to and we're seeing that in the population.

IE increased protein uptake in winter months where the conditions meant their diets were exclusively meat in that period of the year. In modern peoples the more meat a person consumes the more chronic kidney disease we find(the liver gets hit too)*. A drop in vitamin C in winter months might be in the mix too and they're actually also showing signs of scurvy. Ditto for vitamin D if they were still dark skinned. Note that the authors mention rickets, a sure sign of a deficiency in that vitamin. Unless they had access to fish sources and ate them whole D would be harder to absorb as land mammal meat isn't nearly as abundant in it and things like eggs would be seasonal if present at all. Note too that these changes are seen more in adolescents in the sample. Growing bodies in puberty are going to be more vulnerable to such stresses.

So an extreme seasonal shift in food sources might explain this and might explain the annual patterns. In the brief summer they find more plant based food and more carbs and absorb more vitamin D and C, then that gets shut down as the long winter hits and they're reduced to an almost exclusively animal protein diet. Plus they may have not been great hunters at this stage and you could add in low level starvation too.






*Eskimos who have adapted to a meat based diet have much larger livers to cope with it and produce more urea, though even with their adaptations(and contrary to popular belief, AKA BroScience) the traditional Eskimo diet causes the same level of coronary heart disease as a bad western diet and a far higher rate of stroke. Both of which have dropped as people introduced more western foods into the traditional fare. They also have dietary sources of vitamin D in the large amounts of fish they eat and vitamin C because much of their diet was raw.

[Adam Khor]

It does seem very odd that a big hominin of all things would be able to hibernate, when the only other primate that does is a dwarf lemur the size of a rat that only survives off fat accumulated on its tail...

[Wibbs]

That's what I'm thinking AK. Maybe a state of torpor rather than full hibernation, but I still don't buy it. Not on that evidence. For a start hibernators need to be able to store fat in sufficient amounts to get them through their hibernation phase, plus animals that do this like bears for example don't suffer bone changes like the ones described in Atapuerca folks, because bears are adapted to it as a survival strategy. And if it were a survival strategy in hominids in cold climes surely we would have held onto it as an advantageous adaptation, or see evidence of it elsewhere, or even in our own modern human bodies? OK the Atapuerca guys look quite different to us on the surface and mostly above the neck, but we're clearly both variations on the same theme.

Personally I think my diet hypothesis above where these changes are a result of a lack of adaptation to a local, likely swift shift in climate makes for far more sense than a fundamental change in hominid and primate biology and one that is not seen anywhere else.

[Adam Khor]

I agree. It's an interesting concept all the same.

I don´t think it would be very safe, tho! We have good evidence that even cave bears sometimes were killed by other, year-round active predators while hibernating. Cave leopards, cave lions and perhaps even cave hyenas preyed on sleeping bears it seems, which doesn´t seem all that weird considering even Siberian brown bears today are killed by tigers while slumbering.

During the time of these Sima hominins, as I understand it, the giant lion Panthera leo fossilis and the jaguar Panthera gombazsoegensis were roaming about. If you have seen those videos of leopards preying on sleeping dogs, so stealthily the dog doesn´t even know the cat is inches away until the very last moment...