A new paper in the journal Nature makes the case that "Hobbit" remains on the island of Flores are 110,000 to 60,000 and that the associated stone tools are not younger than 50,000 years BP. Thus, hobbits and modern humans may have co-existed no longer than Neanderthals did in any one place, rather than co-existing for 30,000+ years as suggested by previously estimated dates.
This actually makes a great deal of sense. In every other case where modern humans co-existed with another hominin species, or even with another highly diverged and technological disparate population, the "less advanced" population quickly went extinct leaving only minor genetic traces in the surviving population and perhaps some tiny isolated relict populations.
Hobbits (a.k.a. Homo Florensis) are certainly the most plausible candidates to have admixed with early Papuans and Australians who arrived in Flores ca. 50,000 years ago to give them high levels of Denisovan admixture (although they may have been genetic close relations of a taller and larger Denisovan species from the mainland that experience island dwarfism on Flores and this size disparity may have made love rather than war a more palatable option upon encountering them since they wouldn't have been as threatening to modern humans).
But, there is no genetic evidence to suggest a sustained period of admixture as recently as 12,000 to 18,000 years ago, with 32,000-38,000 years of co-existence, when the previous dates suggested that Hobbits went extinct on Flores. We would also expect significant change in the hobbit phenotype over that time period as hybrid individuals came into being for sustained periods of time. If that was the case, modern humans on Flores would have much higher proportions of archaic admixture than Australian Aborigines or Papuans who swiftly moved on from Flores to more distant destinations on what was apparently a one way voyage. Yet, this is not what we observe.
This does leave up in the air the speculative linguistic evidence that Hobbit language learners may have influenced the language of Flores (making it simpler), and the plausibility of the oldest oral histories regarding people who might have been Hobbits, each of which seem more doubtful at a time depth of 50,000 years than they do at a time depth of as little as 12,000 years.
One possibility that could partially reconcile the two lines of evidence is that a minority of Hobbits who survived encounters with modern humans relocated to less accessible locales and were more wary of modern humans after negative initial encounters with them, but still persisted in small, isolated relict populations whose remains have not been located yet that gave rise to the oral histories at least.
4 comments:
As I understand it Homo floriensis is anatomically very primitive, to the point that some people don't even think they should be classified as Homo. Denisovans would be expected to look more like Neanderthals or modern humans, like Dali or Narmada. Island dwarfing is possible but that wouldn't them primitive morphology. Even late Home erectus soloensis would probably be too divergent to fit as Denisovans. We don't actually know who was living in most of Southeast Asia prior to the arrival of modern humans, since the dates for Solo man are up in the air (50 to 500 thousand years) and there are very few pre-modern fossils outside of Java and Flores.
Almost every culture has stories about little people. It's tempting to try to connect them to real pre-existing small humans like Pymgies or Negritos or H. floriensis as appropriate, but I don't think it's justifiable.
I understand the argument, but it is very hard to ignore the very strong coincidence, particularly without any other direct evidence from remains of Denisovans to show what they looked like.
The absence of fossil or archaeological evidence across Asia in the Middle Pleistocene also makes any effort to posit an alternative that replaced H. Erectus challenging. Shouldn't wholesale replacement of one pre-H. Sapiens species by another pre-H. Sapiens species in a huge geographic area at least leave evidence in the form of a different toolkit with relics left all over the place to be discovered?
You'd also think that with all the ash spewing volcanos that Indonesia has that at least some of them would have led to excellent preservation of archaic homo.
Maybe there just hasn't been enough fieldwork done yet and we will get a wave of discoveries as war and politics and poverty subside as barriers to research, which had a long lull after the brief burst of 19th century colonial era fieldwork. But, in the absence of any other evidence, it is very hard not to connect the dots, and given its somewhat more basal position, I wouldn't be surprised at all if Denisovans were considerably more primitive in phenotype than Neanderthals.
I don't know what to make of the stories about little people (and I wouldn't agree that all cultures have them, although most cultures in Europe and many completely independent cultures do). I'd also be interested in the state of the literature on how long oral history can sustain stories with some semblance of connection to reality (or for that matter, how long they can sustain any story). There are a handful of fairy tales that have been dated to PIE by means similar to linguistic ones, but that is only 6,000 years, not 50,000.
"This actually makes a great deal of sense".
I agree. I have always seen it as a problem as to how modern humans managed to bypass Flores yet colonised Alor and Timor.
"Hobbits (a.k.a. Homo Florensis) are certainly the most plausible candidates to have admixed with early Papuans and Australians who arrived in Flores ca. 50,000 years ago to give them high levels of Denisovan admixture"
I think they are extremely unlikely to have been the source.
"As I understand it Homo floriensis is anatomically very primitive"
That's the situation as I understand it also. Island dwarfing of an erectus-derived species seems most likely.
"Even late Home erectus soloensis would probably be too divergent to fit as Denisovans".
Yet I'm beginning to think they are exactly the group who supplied the Denisovan element to New Guinea. The problem does arise, though, of how such a group could have provided the genes for high altitude living in Tibetans.
"Maybe there just hasn't been enough fieldwork done yet and we will get a wave of discoveries as war and politics and poverty subside as barriers to research"
I think Myanmar will prove to be extremely interesting in that regard. To me it has long seemed to be the region where mt-DNA began its spread, and obviously provided the main route between South and Southeast Asia.
"I wouldn't be surprised at all if Denisovans were considerably more primitive in phenotype than Neanderthals".
Probably correct as it seems from the mt-DNA evidence that Neanderthals formed from a Denisovan population that had become isolated in some as yet unknown region. I tend to agree with those who see 'Denisovan' as Homo heidelbergensis. I also think it likely that some level of heidelbergensis is responsible for the change in SE Asian erectus to soloensis.
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