Mystery Tooth Fossil

Discussions unearthing human history including cultural anthropology, linguistics, etc.

Mystery Tooth Fossil

Postby BioWizard on October 22nd, 2017, 8:36 am 

User avatar
BioWizard
Forum Administrator
 
Posts: 12628
Joined: 24 Mar 2005
Location: United States
Blog: View Blog (3)


Re: Mystery Tooth Fossil

Postby BadgerJelly on October 22nd, 2017, 10:03 am 

Interesting, but likely a mistake?
User avatar
BadgerJelly
Resident Member
 
Posts: 4500
Joined: 14 Mar 2012


Re: Mystery Tooth Fossil

Postby Forest_Dump on October 22nd, 2017, 10:42 am 

The saying is that extra-ordinary claims need extra-ordinary support but this one, IMHO, is not necessarily all that wild even though I couldn't see any image of the fossils. But for that very reason I would want someone to have a hard look at the dating and someone better than me (like David Begun) look at the teeth. Because it is very plausible. And here's why.

Back just after his Planet of the Apes paper in Scientific American came out, I had a chance to shoot some stick and drink wobbly pops with Begun and do some arguing. At the time I was really questioning the role of selection in human evolution and had always had an interest in Dryopithenes since my undergrad days. So some of Begun's ideas made me think and I was going way beyond where he was willing to go at the theory level. So, from Begun's paper I got to think that the big expansion of tropical forest in the Middle Miocene pushed some primate pipulations north towards the fringes in Europe with isolation of populations leading to genetic drift. Then as the forests shrank these populations came back to increased proximity leading to gene flow and a kind of hybrid vigor (i.e. the example of olive baboons and another species interbreeding to produce greater diversity in the young than seen in the parents - sorry can't remember the citation).

So this case could easily fit this scenario. In my idea, the gene flow/hybridization hypothesis leading to the specific traits leading to hominines appears to have sparked around of shortly after 7 MYA when the apes were being pulled back into Africa but at 9 MYA there were tons of different ape species and even fossil "genera" (I use the quotes because of the difficulty of fossil taxonomy) and the process of forest shrinking had begun, pulling these previously dispersed populations along the mosaic margins back together. So this could easily represent an early example of this process leading to hominids, or a populations with the right pre-adaptation (i.e., the idea without the teeth actually having any real adaptive advantage just more of a chance configuration), etc.

So it is not really all that out of line with the possibilities so not only would I not dismiss the idea out of hand but I would actually want to take a very close hard look at what they got. It could very well be.
User avatar
Forest_Dump
Resident Member
 
Posts: 8718
Joined: 31 Mar 2005
Location: Great Lakes Region
doogleszetreque liked this post


Re: Mystery Tooth Fossil

Postby BioWizard on October 22nd, 2017, 11:35 am 

Thank you Forest!

As an aside, I too have become apprehensive over the years of over application of NS to humans. At least in part because we’re so good at modifying our world to fit us, allowing for much more dirft that what is seen in other organisms. Not saying it doesn’t happen to us - just that I’d like to see enough evidence before I accept that a certain trait was actually advantageous.
User avatar
BioWizard
Forum Administrator
 
Posts: 12628
Joined: 24 Mar 2005
Location: United States
Blog: View Blog (3)


Re: Mystery Tooth Fossil

Postby zetreque on October 22nd, 2017, 11:59 am 

To put some perspective on this, do we say that neanderthal's and humans diverged only 600,000-900,000 years ago?
And they say the first wave into Europe of humanoids was about 1.8 million years ago.
User avatar
zetreque
Forum Moderator
 
Posts: 3130
Joined: 30 Dec 2007
Location: Paradise being lost to humanity
Blog: View Blog (6)


Re: Mystery Tooth Fossil

Postby Braininvat on October 22nd, 2017, 12:32 pm 

The tooth being found in sand/gravel, I would want to know more about the dating process and margin of error*. I like FG's point about dispersed pops coming back together. Maybe this is a Euro ape that happened to have a more hominin tooth configuration, which was making its way back towards Africa (driven by? drought, cold spell, foliage change....) and then hybridizing with other species and the tooth configuration becoming more adaptive.

* not a real question - I can find the original paper

* also, do we assume they found the tooth, in that Ur-Rhine spot, where the body fell, or this being an old and large river, could it have started out in the Swiss Alps or elsewhere?
User avatar
Braininvat
Resident Member
 
Posts: 5767
Joined: 21 Jan 2014
Location: Black Hills
doogles liked this post


Re: Mystery Tooth Fossil

Postby Forest_Dump on October 22nd, 2017, 1:54 pm 

It appears I lost a post. Oh well. Since it is still too cold to go out digging although I have too today since I could be frozen out for the year within days...

Braininvat wrote:The tooth being found in sand/gravel, I would want to know more about the dating process and margin of error*.


Yeah dating is an issue as well as the question of whether the teeth belong together, etc.

Braininvat wrote:Maybe this is a Euro ape that happened to have a more hominin tooth configuration, which was making its way back towards Africa (driven by? drought, cold spell, foliage change....) and then hybridizing with other species and the tooth configuration becoming more adaptive.


This is definitely where my interest lies as I will touch on. So...

Braininvat wrote:also, do we assume they found the tooth, in that Ur-Rhine spot, where the body fell, or this being an old and large river, could it have started out in the Swiss Alps or elsewhere?


Yeah but the key is it is in Europe, not Africa.

zetreque wrote:To put some perspective on this, do we say that neanderthal's and humans diverged only 600,000-900,000 years ago?
And they say the first wave into Europe of humanoids was about 1.8 million years ago.


All fine and there is the potential for comparisons but we are still dealing with topics with 5 - 7 million years difference.

I am certainly cautious about "teeth-only" interpretations. I am from the era that thought Ramapithecus was a viable human ancestor of about the same time but that was based on teeth and a couple of jaw scraps. We since changed this to Rama and Sivapithecus being sexual dimorphism in an Orang ancestor. So I like the idea of a human-chimp ancestor having more generalized (less specialized? less evolved?) than chimps and thus same for the human-gorilla ancestor and even the human-orang common ancestor, etc. with, therefore, the dentition of all these forest apes potentially being the result of somewhat heavier selective pressure towards a common, specialized end in the forests. This would then also be a model for the specialized, different direction taken later by the robust Australopithecines.

In other words, I lean towards "our" line being long a generalized jack of all trades living in mosaic environments around the fringe of the tropical forests as it grew and then shrank (out and then back into Africa) through the Middle and Late Miocene. This specific find could well be a common ancestor of humans and gorillas (or even humans and Orangs although that split was probably much earlier) or after that split but before the human chimp split, etc. with all of those having more human-like than chimp or gorilla-like teeth.

BioWizard wrote:As an aside, I too have become apprehensive over the years of over application of NS to humans. At least in part because we’re so good at modifying our world to fit us, allowing for much more dirft that what is seen in other organisms. Not saying it doesn’t happen to us - just that I’d like to see enough evidence before I accept that a certain trait was actually advantageous.


Yeah, I agree we cannot rule out NS in any way. I just found it was so hard to emprirically evaluate to test in any way ideas like differential reproductive success based on some hypothetical adaptive advantage when we really only have a shoe-box of bone scraps per 100,000 years. Not to mention that we are talking about critters that probably had a low population density, relatively low birth rate, etc. So I found it useful to just ignore NS as just-so stories and think about drift, founder effects, gene flow, effects of "hybridization", etc., agains what we are learning about the geography, paleo-environments, etc.

This one almost appears to just fit right in with what could have been predicted.
User avatar
Forest_Dump
Resident Member
 
Posts: 8718
Joined: 31 Mar 2005
Location: Great Lakes Region
doogles liked this post



Return to Archaeology

Who is online

Users browsing this forum: No registered users and 2 guests

cron