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Those Moroccan Skulls...

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1239091.  Thu Jun 08, 2017 5:03 am Reply with quote

By which I mean to refer to this story.

Fossils discovered in Morocco are the oldest known remains of Homo sapiens, scientists reported on Wednesday, a finding that rewrites the story of mankind’s origins and suggests that our species evolved in multiple locations across the African continent.

I'm wondering how it has been determined that these are Homo sapiens - not that I'm in position to dispute this but the supra orbital ridges and the lateral portions of the orbits (formed by the zygomatic bone) are conspicuously heavy and the article tells me that the brain is a different shape to the human brain so by what criteria are the remains considered human?

The zygomatic arch also appears to be absent although I'm assuming that this is because it was not preserved rather than because it was absent to begin with.

1239180.  Thu Jun 08, 2017 9:27 pm Reply with quote

If not human, then what?

1239245.  Fri Jun 09, 2017 7:51 am Reply with quote

An intermediate form.

1239261.  Fri Jun 09, 2017 10:15 am Reply with quote

The definition of a species is is really just a vague venn diagram.

The two-toed tribe and awesome-butt tribe are still human, even if their physical features differ from what we consider to be standard human.

1239277.  Fri Jun 09, 2017 11:28 am Reply with quote

But proto-human?

After H. erectus but predating H. sapiens perhaps... but seemingly the decision has been made that these examples exhibit speciation that can be characterised as 'human' ie H. sapiens but the reasons why the elongated brain and heavy-set facial features are not considered sufficient to classify them as a separate species are not given. I've heard no mention of DNA evidence but since species are defined by potential for viable interbreeding between populations this would be the definitive data.

I was just wondering if anyone had seen a more scientific article on this. Nature to the rescue!

Genomic evidence

An earlier origin for H. sapiens is further supported by an ancient-DNA study posted to the bioRxiv preprint server on 5 June6. Researchers led by Mattias Jakobsson at Uppsala University in Sweden sequenced the genome of a boy who lived in South Africa around 2,000 years ago — only the second ancient genome from sub-Saharan Africa to be sequenced. They determined that his ancestors on the H. sapiens lineage split from those of some other present-day African populations more than 260,000 years ago.

Hublin says his team tried and failed to obtain DNA from the Jebel Irhoud bones. A genomic analysis could have clearly established whether the remains lie on the lineage that leads to modern humans.

Palaeontologist Jeffrey Schwartz, at the University of Pittsburgh, Pennsylvania, says the new finds are important — but he is not convinced that they should be considered H. sapiens. Too many different-looking fossils have been lumped together under the species, he thinks, complicating efforts to interpret new fossils and to come up with scenarios on how, when and where our species emerged.

“Homo sapiens, despite being so well known, was a species without a past until now,” says María Martínon-Torres, a palaeoanthropologist at University College London, noting the scarcity of fossils linked to human origins in Africa. But the lack of features that, she says, define our species — such as a prominent chin and forehead — convince her that the Jebel Irhoud remains should not be considered H. sapiens.

Same article as above.

So there is some debate still amongst experts as well as requests for clarification from interested readers.

Last edited by Celebaelin on Sat Jun 10, 2017 12:14 pm; edited 1 time in total

1239312.  Sat Jun 10, 2017 3:31 am Reply with quote

Early H. sapiens genealogy is not all that clear, but other fossils of comparable age (including some from Jebel Irhoud) have been classified as H. rhodesiensis.


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