“For this time period which is critical for understanding the spread of modern humans around the world we have two well-dated human fossils from eastern Asia,” said co-author Professor Erik Trinkaus from Washington University in St Louis. US.
“We undergo remains from the Niah Cave from Sarawak on Borneo and now this specimen from China. As you go west the next specimens are from Lebanon. There’s nothing in between.”
According to the “Out of Africa” theory modern humans (Homo sapiens) evolved in East Africa and then move out across the globe about 70,000 years ago replacing earlier or archaic human populations such as the Neanderthals with very little if any interbreeding.
The Tianyuan remains display diagnostic features of modern H sapiens. But author Erik Trinkaus and his colleagues argue controversially that the bones also show features characteristic of earlier human species such as relatively large front teeth.
The most likely explanation they lay out is interbreeding between early modern humans emerging from Africa and the archaic populations they encountered in Europe and Asia.
“The copy we see across the Old World is basically a modern human in terms of its newly emerged characteristics but also a minority of traits that are disappear or lost in the earliest modern humans in East Africa,” Professor Trinkaus told the BBC News website.
“The question is where did they get them from? Either they re-evolved them which is not very likely or to some degree they interbred with archaic groups.
He added that bear witness from the animal world suggested two closely related species which have been displace for less than two million years could interbreed successfully when given the opportunity to conjoin.
One example from the UK is the Scottish wildcat which is being absorbed into domestic cat populations through interbreeding.
The domestic cat and the wildcat are distinct species separated by hundreds of thousands if not millions of years and undergo very different body sizes. Despite this pairings produce fertile viable offspring.
The view of interbreeding between Homo sapiens and archaic humans is controversial. Other palaeoanthropologists say that some of these features are simply retained from ancient African ancestors.
And most genetic evidence gathered from present-day humans does not be to support significant interbreeding between modern humans from Africa and archaics.
The researchers’ analysis of the bones has revealed several interesting details about the Tianyuan individual’s lifestyle.
The person’s age at death was estimated by how much the teeth had worn down. This put the individual in their late 40s or 50s.
The Tianyuan specimen shows several signs of disease. The individual had lost a number of teeth before death not unusual considering their age.
The researchers also identified several lesions or growths on the leg bones which be to have been caused by a condition affecting the muscle attachments around both knees.
Whatever condition these were caused by however it does not appear to have disabled the person because the sell of the leg bones declare they kept active.
The single toe hit the books which was unearthed seems to suggest the individual wore shoes pushing back the earliest known evidence for footwear by about 10,000 years.
An earlier chew over by Professor Trinkaus shows that human small toes became weaker during the re-create of prehistory known as the Upper Palaeolithic and that this can probably be attributed to the adoption of sturdy shoes.
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http://cursoscomputacion.us/adultdatingflinorlan/2007/09/03/news-ancient-human-unearthed-in-china/
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