Denisovan Jaw Bone Found in Tibet

[shawomet]

https://www.npr.org/2019/05/01/71872901 ... d-to-tibet

[circumspice]

I suspect that more & more Denisovan fossils will be found in Asia, especially if old museum collections are being reviewed.

[Cognito]

I suspect that more & more Denisovan fossils will be found in Asia

Here's a quote from AP News: "The Nature paper points out similarities to a fossil jaw reported in 2015 that had been dredged by a fishing net off the coast of Taiwan. So maybe the Denisovan range can be extended that far south, he said."

See: https://apnews.com/f3ee57c9a53e41ef846442de09397c29

Looks like others already suspect that the Denisovans were widespread. If they could survive Tibet, they could certainly trek across Beringia. That could explain some of the early sites that are so contentious to mainstream archaeologists (Valsequillo, Calico, Cerutti, etc.). Human remains are incredibly rare, but lithic tools last forever.

[Minimalist]

I suspect that more & more Denisovan fossils will be found in Asia, especially if old museum collections are being reviewed.

It is hard to look for something if you don't know what it is that you are looking for. The earliest papers on Denisova Cave were published around 2010. As you suggest, Circ, people should now be highly motivated to re-evaluate earlier finds for possible re-classification.

[circumspice]

I suspect that more & more Denisovan fossils will be found in Asia, especially if old museum collections are being reviewed.

It is hard to look for something if you don't know what it is that you are looking for. The earliest papers on Denisova Cave were published around 2010. As you suggest, Circ, people should now be highly motivated to re-evaluate earlier finds for possible re-classification.

It's even harder to look for something you didn't know existed... The 'discovery' of the Denisovans was an accidental discovery. They were reviewing the unclassified bones & that tiny finger bone led to a DNA analysis to determine if the remains were HSS or HN. According to the anthropologists, the discovery of a third unknown Homo hominid in the same cave was totally unexpected. Now they're saying that there are 3 subspecies of Denisovan, two of which are closely related to one another & the third is only distantly related. Wow. The human family tree is getting bushier & more complicated.

[Minimalist]

I doubt they were separate species in the classic sense of the word. In fact, it seems there was a whole lot of interbreeding going on. Kind of like Spring Break in the paleolithic!

[Cognito]

I doubt they were separate species in the classic sense of the word.

There was enough cross breeding between human types, such as Neanderthals, Denisovans and "unknown others", that introgression of genetic material occurred across genomes where advantage was conferred. By strict definition, these were all the same species since they could interbreed successfully. I am still a fan of M. Wolpoff's Multiregional Hypothesis. See: http://www-personal.umich.edu/~wolpoff/ ... gional.PDF

BTW, Wolpoff believes the "unknown others" were Asian H erectus or their direct descendants (source: personal correspondence).

[Minimalist]

I am also a multi-regionalist with the added proviso that I think we are all merely the latest model of Homo Erectus in much the same way that the Nissan 370Z is simply the latest model in the long-running Z series.

HE was around long enough to do the heavy evolutionary lifting!

[circumspice]

I am also a multi-regionalist with the added proviso that I think we are all merely the latest model of Homo Erectus in much the same way that the Nissan 370Z is simply the latest model in the long-running Z series.

HE was around long enough to do the heavy evolutionary lifting!

You're definitely thinking pretty much the same thing I was thinking Min. Those 5 skulls from Dmanisi drove a spike in the theoretical canon of anthropology... There are lumpers & there are splitters... Obviously, splitters are glory hounds, wanting to make a big splash. Lumpers are more prosaic. To me, a dog is a dog, whether it's a Chihuahua or an English mastiff. Put them side by side & you must say 'Yup, they're dogs'...

Here's an interesting article about that:

https://www.smithsonianmag.com/smart-ne ... t-2819218/

[circumspice]

Here's a decade old article that speculates that either H habilis or A afarensis migrated in & out of Africa long before H erectus made their first forays out of Africa to become the ancestral line of H floresensis. I wonder if they'll find anything definitive in our lifetime?


https://www.nytimes.com/2009/04/28/scie ... obbit.html

[Cognito]

I am also a multi-regionalist with the added proviso that I think we are all merely the latest model of Homo Erectus

H erectus started out like a full size sedan, but with a 4 cylinder engine. Their bodies from the neck down were incredibly similar to H sapiens today. However, it took 1.5 million years for their brains to approach the size of current day H sapiens.

"Cave men don't need brains." Grug, The Croods.

[kbs2244]

"There was enough cross breeding between human types, such as Neanderthals, Denisovans and "unknown others", that introgression of genetic material occurred across genomes where advantage was conferred. By strict definition, these were all the same species since they could interbreed successfully"

What if the result of this interbreeding was sterile ?
I am thinking of a mule like result.
Are they a new species?

[circumspice]

"There was enough cross breeding between human types, such as Neanderthals, Denisovans and "unknown others", that introgression of genetic material occurred across genomes where advantage was conferred. By strict definition, these were all the same species since they could interbreed successfully"

What if the result of this interbreeding was sterile ?
I am thinking of a mule like result.
Are they a new species?

If a cross is sterile, that genetic line will not continue. Obviously. There are plenty of sterile hybrids in the world. But there are also plenty of fertile hybrids. They just don't reproduce true to type. (e.g. the garden seed industry)

Horses have 64 chromosomes, donkeys have 62 chromosomes. Mules have 63 chromosomes.

All male mules are sterile. Sometimes, female mules are fertile. There are two indisputable cases on record & several anecdotal cases that are considered to be valid. With the advent of DNA testing & whole genome sequencing, there are likely to be more indisputable cases cropping up.

[Minimalist]

What if the result of this interbreeding was sterile ?

You've got it, KB. If it was sterile we wouldn't know it happened and we would not see neanderthal genes showing up in hss dna outisde of Africa but not inside of it.

I still think this whole "species" argument is overblown.

[Cognito]

You've got it, KB. If it was sterile we wouldn't know it happened and we would not see neanderthal genes showing up in hss dna outisde of Africa but not inside of it.

Absolutely true. Neanderthal as well as Denisovan genes are included in the H sapiens genome. Most likely H erectus also, but we don't have any material to test yet and it probably would look very similar to our genetics anyway.

I still think this whole "species" argument is overblown.

Min, I agree with you that we are a latter day H erectus model. The Multiregional Hypothesis states that there was always enough gene flow between isolated groups to keep us in the same species.