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Comparison of Modern Human and Neanderthal skulls.

Prehistoric teeth found in China may point to mysterious new human species

The more research that is done into the prehistoric origins of humans, the more crowded it gets.

According to a new study, there may well have been multiple species of primitive humans between 60,000 and 120,000 years ago – including a mysterious people who do not fall under the categories of either Neanderthals, Denisovans, or modern humans.

Skull fragments and teeth discovered in 1976 in a cave in Xujiayoa, China are raising surprising questions about the prehistoric origins of humanity. Dental remains were recovered from four different individuals, and were examined for size, shape and surface of the teeth, as well as other defining characteristics. When the teeth were compared to a database of over 5,000 teeth of known species, María Martinón-Torres of the National Research Centre on Human Evolution found that they did not match any of the accepted hominids. 

Shape, size, placement and wear on teeth are indicators of species.

Shape, size, placement and wear on teeth are indicators of species. Credit: Martinon-Torres

BBC Earth reports, “We know there were as many as four other early humans living on Earth when modern humans were still confined to Africa. The Neanderthals lived in Europe, the Denisovans in Asia and the "hobbit" Homo floresiensis in Indonesia: plus there was a mysterious fourth group from Eurasia that interbred with the Denisovans.”

The question is now whether the teeth represent a hybrid of Denisovans and modern humans, or whether scientists have an entirely new human species on their hands.

Martinón-Torres and colleagues recently published a study in the American Journal of Physical Anthropology , providing a comparative analysis of the teeth found in northern China, and stated that the teeth are different from those of modern humans, Homo sapiens. The remains possess some primitive features similar to, but not exactly matching Neanderthals or Homo erectus.

“Teeth are like ‘landscapes in miniature’. Each of those slopes, grooves, valleys define a pattern or combination of features that can be distinctive of a population,” Martinón-Torres told BBC Earth.

While the findings are surprising and mysterious, experts are reluctant to confirm it represents a whole new species. "What we have seen is an unknown group for us," continued Martinón-Torres. "It's not H. sapiens and it's not H. neanderthalensis . They have a mixture of something very primitive, which is currently unknown. We cannot go further to say it's a new species because we need to compare it to other things."

Still other researchers insist that while further research needs to be done, the teeth are unique enough to represent an unknown variant based on their surface features alone.

A mix of hominid (genus Homo) models; (from right to left) H. habilis, H. ergaster, H. erectus; H. antecessor - male, female, H. heidelbergensis; H. neanderthalensis - girl, male, H. sapiens sapiens.

A mix of hominid (genus Homo) models; (from right to left) H. habilis, H. ergaster, H. erectus; H. antecessor - male, female, H. heidelbergensis; H. neanderthalensis - girl, male, H. sapiens sapiens. Public Domain

These aren’t the first potential ancient humans to have confounded researchers. In 2013 a Royal Society meeting on ancient DNA revealed a dramatic finding – the genome of one of our ancient ancestors, the Denisovans, contains a segment of DNA that seems to have come from another species that is currently unknown to science. The discovery suggested that there was rampant interbreeding between ancient human species in Europe and Asia more than 30,000 years ago. But, far more significant was the finding that they also mated with a mystery species from Asia – one that is neither human nor Neanderthal.

Could there be a connection between the Chinese remains and that unidentified branch of humanity?

Mark Thomas, an evolutionary geneticist at University College London said of the 2013 DNA find, “What it begins to suggest is that we're looking at a 'Lord of the Rings'-type world - that there were many hominid populations.”

China is home to another controversial prehistoric population – the Red Deer Cave people, dated between 14,500 and 11,500 years. Fossils of the early hominids were discovered in a cave in southern China . While their facial features do not resemble modern humans, experts are reluctant to classify them as a unique species pending DNA extraction.

Red Deer Cave people, skull and reconstruction.

Red Deer Cave people, skull and reconstruction. Wikimedia, ( CC BY 2.5 )

If the Xujiayoa teeth studied by Martinón-Torres and colleagues do reveal an ancient Asian ancestor, history books and the conventional theory which says Africa was the cradle of modern humans will have to be changed.

Human evolution is not as simple as we like to think, but as more remains and fossils are recovered, especially with the aid of DNA evidence, these mysteries may quickly be resolved. The further we proceed into our future, the more we reveal about our ancient past.

Featured Image: Comparison of Modern Human and Neanderthal skulls. (CC BY-SA 2.0)

By Liz Leafloor

Comments

Roberto Peron's picture

I think individual and species variation is underestimated often.  This may not be a new species of hominin at all but simply a variation perhaps of the Red Deer Cave People.  Myself I tend to support the Multi-regional Theory and I think ancient humans were spread around the globe including the Americas and evolved on their own independent of what was going on in Africa.  Americas you say?  Yes!  Why did the famed Louis Leakey come to America (the Calico Hils, California) to prove ancient human ancestors evolved in the Americas as well as Africa?  He had a reason and he had a suspicion.  What did he know?

 

riparianfrstlvr's picture

I just heard that a 12,000 year old skeleton of a boy from the Clovis culture was found near Livingston Mont. I read some of what Dr. Melba Ketchum wrote about it, this is one thing she said:

It has been proven that Native American populations contain admixtures from both Neanderthaland and Denisovan hominins. Furthermore, Native Americans have more Denisovan and Neanderthal DNA than Europeans and the Denisovan and Neanderthal DNA that they carry is different than that carried by Europeans. Finding a substantial admixture of both of these extinct hominins in a population is uncommon and adds yet another layer of mystery as to their origins. Since it is unknown whether any Neanderthal or Denisovan individuals inhabited North Americain the past, these admixtures currently support a potential ancient Siberian origin for Native Americans since it has been established that Neanderthals and Denisovans interbred in Siberia     well before the Beringians inhabited the land bridge. It seems that the further back human remains are sequenced, the more complex the interrelationships between different groups ofpeople and the more muddled their geographic origins become.

 

riparianfrstlvr

Roberto Peron's picture

From what I have found out it appears that North Amreican Native Americans have more Neanderthal DNA than Europeans.  South American Natives have more Denisovan DNA.  Of course the population with the most Denisovan DNA are the people of Southeast Asia.  And we also know that in Siberia the Denisovans interbred with Neanderthals.  Among Native Americans some have oral traditions that tell of their ancestors crossing the Beringer Land Bridge while others have no such stories and say that their ancestors have always been in the Americas.  Others have oral traditions telling of how their ancestors came across the ocean waters to the Americas.  The idea that all Native Americans (North and South) came across the land bridge is a bit of wishful thinking IMO.  I think some did and others came be boat while others, very possibily, never came from anywhere as they were always here.  

One of the BIGGEST mistakes of Anthropology has been to not take Native oral traditions seriously enough but simply to pass them off as myths and legends.  Ironically, as new evidence is uncovered we are beginning to find that many of the Native American oral tradtions are correct and not mythical at all.  And so the quetion is what more might we learn if we listened closely to the oral traditions, took them a bit more seriously, and stopped with our egocentric fantasties that we have it all figured out?  Likely we might learn some TRUTH and FACT which would replace the MYTHS we hold today!  Of course that would mean many of our pet theories would have to go to the trash but that's where many of them belong anyway.

The more we uncover about ancient human origins the more we see clearly that the rise of modern humans is more like a twisted bush than a tree.  

from what i know native americans have had absolutly nothing to do with the interbreeding with neanderthals, and there is evidence of this, while man has a great immune system which came from out neanderthal cousins which the natives of the americas do not have. so when white men went over with a stonge immune system from the neanderthals, the natives died of diseases that there immune systems couldnt handle, and another thing there are no red headed natives like there are red headed white people becuase red hair gene originated from the neanderthals. native american are actually the most purest of homo sapiens because them missed out on alot of the interbreeding. just wanted to have my input. thankyou for taking time to read. p.s the land bridge they could be talking about does exist, you can walk from alaska to russia ( i think it russia or siberia) in november time, some of the sea freezes up but its very dangerous to cross. i am talking fact. you need to do more research before typing something so silly

Roberto Peron's picture
To the contrary Native Americans have much to do with Neanderthal interbreeding.  A complete and accurate Neanderthal DNA sequence released just last year (2014) as was the genome sequence results of a Siberian child that connects Native Americans to Europeans.  A few years ago researcher David Reich at Harvard Medical School discovered a genetic connection between Northern Europeans and Native Americans.  Reich postulated that a "ghost" group must have existed at one time linking Native Americans to Europeans but that group is now extinct in norther Eurasia with both Europeans and a Siberian group that later migrated to the Americans (the Native American "Ancient Ones").       Denisovan DNA is found primarily in Pacific peoples, Australian natives, and modern populations in Southeast Asia.  It is also found in some Siberian populations.  Neanderthal DNA is found in most European populations today and in every group outside of Africa.  When it comes to the group that is the purest Homo sapien it is now a scientific fact that Africans are the purest H. sapien population today NOT Native Americans.     Looking at the Denisovan genome we can discern a greater amount of Neanderthal DNA in Asians and Native Americans than there is in Europeans, in fact.  It has been surmised that H. sapiens coming out of Africa interbred with Neanderthals in Europe and their offspring later migrated into Eurasia and interbred with Neanderthals in Siberia and thus adding more Neanderthal DNA into their genome.  And as we all know the offspring of that second interbreeding with Neanderthals produced the peoples who would eventually migrated into the Americas via the Bering Land Bridge and, thus, become Native Americans.  At least this is one possibility that the DNA evidence supports.  Another possibility is that modern humans, H. sapiens, came out of Africa in two separate migrations into the Levant (Middle East) and populated Europe as well has interbreeding with European Neanderthals who were already in Europe.  Another batch of H. sapiens migrated out of Africa afterwards and they formed families with mixed children of Neanderthals and H. sapiens.     In 2013 a paper was published showing sequencing results of Native American DNA and it contained some surprises.  The results were published in the scientific journal "Nature" by Prufer et al.  The results were the complete genome sequence of a Neanderthal from the Altai Mountains in Siberia.     This sequencing once again established as scientific fact that Native Americans carry both Denisovan and Neanderthal DNA and, in fact, they carry more of it than do Europeans!  However, the Denisovan and Neanderthal DNA found in Native American genes is different than that carried by Europeans who interbred with Neanderthals in Europe.  Not all Europeans carry Denisovan DNA, btw.   I will not ramble on except to say that you are indeed correct Laura about the land bridge between Siberia and Alaska, at least partially.  Yes, as you say, sea ice forms and you can actually walk across from Alaska into Russia but it is rather dangerous.  Another geological fact that we know is there have been several times in the past history of the Earth when that land bridge was not composed of frozen sea ice but was dry land.  This was either due to lower sea levels and/or the rising of the land mass.     I have nothing but great respect for Native Americans as I grew up with them and am part Native American myself.  I do not see it as a problem for that part of me to contain Neanderthal and Denisovan DNA.  That said, it is incorrect to claim that Native Americans are the purest Homo sapiens when, in fact, that statement is NOT supported by the DNA evidence at all.  In fact, the DNA evidence tells us that the peoples of Africa are the purest Homo sapiens (modern humans).   Thank you for your comments and for sharing your opinions on this issue Laura.     References: http://www.nature.com/news/human-evolution-the-neanderthal-in-the-family... http://io9.com/5939148/new-dna-evidence-could-explain-what-happened-to-t... http://dna-explained.com/2013/12/26/native-americans-neanderthal-and-den...   PS--- can someone please tell me why when you type a comment and paragraph once it is published on this site at times the paragraphs do not appear?  It's got me pulling my hair out!!!    

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