Homo floresiensis redated: the long game

The new discovery of further Homo floresiensis remains adds to our body of knowledge while asking as many questions as it answers.

The most significant new information is that floresienses had been on that small island from 700,000 to 55,000 years ago (at the minimum range).

Scientific consensus seems to be that they are a species of Homo.  Although their small stature is suggestive of the Homo predecessor Australopithecus,  it is instead due to insular dwarfism - which means that 700,00 years ago it was already long enough on that small island for it to have evolved smaller to match the scarcity of resources there.

That's an awfully long time to be stuck on an island!  They certainly didn't do much with their time there, compared to the achievements in the span of modern humans.  That indubitably reflects their smaller cranial capacity.

Yet before we disparage a long-static lineage, we need to remember that any such species has to be said to be well-adapted to its environment.  On that basis, they were better adapted than most hominin species, with current evidence showing a lengthier stay on this earth than most others.  That longevity may reflect the stability of the Flores island environment, with little competition from apex predators or other hominin.  Yet it has been said that on available evidence, they disappeared at around the same time modern humans passed through on the way to Australia.  That could be a giant coincidence of the specimens unearthed to date, but it reflects an apparent pattern of Homo sapiens' interaction with other hominin species.

My current questions:

What discussion does this open up about stasis?  There's a lot of possibilities.

Did floresiensis last any longer than 650,000 years?

Were they evolved from Homo erectus?

And in particular, since the original find was entirely due to Mike Morwood seeking an understanding of the migration story of the first Australians, what's the full story of hominin migration between Africa and Australia?  The fossil record suggests there is an awful lot more to be gleaned from digging up all the islands in Indonesia.  Let's hope the past disputes lead to more successful governance of future projects

Flores and toolmakers: Rethinking pre-sapiens hominid evolution

Science is uniquely accepting of new understanding, through new evidence.  (This is, of course, exploited by science deniers, who hide under the veneer of scepticism to push ideology over the balance of evidence.)  Yet most discoveries add to new knowledge, rather than shift paradigms.  Relativity and quantum physics are two of the few examples of abrupt change in the past 100 years.


There is good scientific consensus that the modern human species (Homo sapiens sapiens) first evolved in Africa, left about 60,000 years ago, and arrived in southeast Asia about 45,000 years ago.

However, other human species had left earlier: Homo erectus  first left Africa about 2 million years ago, spread widely, and was to be found as recently as 50,000 years ago in Java. (By contrast, Neanderthals, homo sapiens neanderthalensis, reached Europe between 600,000 and 350,000ya, lasting to 30,000ya.  Tellingly, sub-Safaran Africans have been found to have no Neanderthal DNA, while all other humans have 1-4% DNA from Neanderthals.)

Australopithecus afariensis and Homo floriensis (from Wikipedia)

More recently, the find of Homo floresiensis on the Indonesian island of Flores, has been dated to as recently as 13,000ya, going as far back as 94,000ya.  This is well before the emergence of modern humans, although evidence suggests the two species could have lived in close proximity for a time.

The H floresiensis remains are in fact so recent that they comprise original material, as opposed to fossils, which are rock which replaced (at a later point) eventually-disintegrating bone matter.

Because of the spread of H erectus, it has been speculated that this more recent find is descended from H erectus, and still underwent a dwarfism typically associated with animal species that have migrated to island environments.

Adam Brumm of the University of Wollongong reported recently in Nature  a find of tools in Wolo Sege in Flores that pushed back hominid (which is not to say H sapiens sapiens) occupation of Flores to at least 1,000,000ya.

Recently on ABC Radio, Brumm commented that the working hypothesis is that the tools belonged to an ancestor of H Floresiensis, since they were the only ones there that far back.  He also suggested that, rather than descending from H erectus, H floresiensis descended from an australopithecus species, so is hominid rather than human (Australopiths having evolved into the several homo species, and died out, about 2mya).

The important takehomes are that pre-hominids may have left Africa much earlier than hominds, and that H floresiensis is likely more distantly related to humans than any other homo species.  (Note: current thinking has chimpanzees diverging from humans about 5-6mya, which would put floresinensis divergence at 2-5mya.)
If Brumm's comments are correct, there may need to be a name change from H to A floresiensis.

This accords well with plenty of the other evidence on H floresiensis (albeit  floresiensis likely underwent further evolution apart from dwarfism).

Brumm called it an exciting time to be in the field, but also said they now needed new sedimentary basin finds [in Flores] to explore the period from 2mya to 1mya.  Despite the science, paleontology finds are still a matter of skilled luck as much as anything else.


Other references:
An ABC report on the tool finds;
anthropologist John Hawkes comments on the tool finds

Lewis Black on creation; Bronowski on humans

Something to round off the week. A comedian gives a perspective on creationism that is quite apposite - and funny. Lewis Black doesn't need to engage from a rationalist point of view - but it's not a rationalist argument anyway.

In the process he has a dig at the lack of commitment to solar energy.

Don't know the bloke, but he seems all right on the whole. (Again, thanks to Bill for the reference.)


I also watched some of a BBC documentary series from 1973, Jacob Bronowski's The Ascent Of Man (sic). It's very specifically Dr Bronowski's perspective, and despite the date, I can't fault his take on the emergence of human civilisation. On the basis of what I've seen so far, well worth a wat

Floresiensis claim: ivory tower science

A fresh claim had been made that the putative homo species Floresiensis (the so-called "hobbit" found in Flores in Indonesia) were actually modern humans suffering dwarf cretinism.

This from Peter Obendorf, Charles Oxnard, Ben Kefford, of Melbourne's RMIT and the University of Western Australia, published in the Proceedings of the Royal Society.

The claim is that the dimensions of the fossil specimens were exactly equivalent to those of dwarf cretins, and thus displayed iodine deficiencies [resulting in thyroid malfunction]. "Dwarf cretins grow not much more than one metre and their bones have distinctive characteristics very similar to those of the Flores hobbits," according to Obendorf.

skull size relative to human

The immediate impression from the article in today's Herald is that these are scientists from other disciplines, not paleontology. The suspicion that they're taking the evidence out of context is borne out by the fact that they haven't studied the actual relics, and they misconstrue aspects of the fossils including, an area of skull that was actually excavation damage, rather than evidence supporting the new thesis. (From the paper's abstract:"We find that the null hypothesis (that LB1 is not a cretin) is rejected by the pituitary fossa size of LB1, and by multivariate analyses of cranial measures.")

The press release on RMIT's own site illustrates how much of a speculative exercise it was, initiated by Obendorf spotting a superficial link between floresiensis and historical pictures of cretins(!) Obendorf is hard to find at RMIT, but he's described as a human ecologist, which can be somewhat helpful but ultimately not too encouraging from a paleontological perspective.

Amongst other things, Colin Groves from ANU said the new paper "also ignored the fact the hobbits had primitive chins unlike those of modern humans".


Incidentally, the Herald article seems to be sourced from two separate reports, one of which refers to Floresiensis descent from Homo erectus; the other from australopithecines. The former, from AFP, is the more usual lineage description. The latter, from the Herald's own reporting, is not really sufficiently precise: australopithecines are much older ancestors of erectus. Reporters are not usually trained in anthropology.

One curiosity: the abstract also says, inter alia: "We show... how remains of cretins but not of unaffected individuals could be preserved in caves." That's quite a claim, if it's based on chemical science. It could easily, however, be based on speculation of social circumstance. I don't know, not having read the full article, but since the paper somewhat reeks of speculative application of anotomical science, I'm not going to hold my breath on the outcome.