It seems that Homo Floresiensis was actually someone with Downs Syndrome.
If this holds up, the kiddie-scientist inside me will be rather disappointed.
Bother. Next thing you know, they’ll be claiming that the orc skeleton wasn’t real, too.
So it was Sam all along?
d&r
"Hobbitses? What’s Hobbitses, my precious?
Are the juicy? Are they Scrumptious? Has they got trisomy 21? Gollum!"
I wrote an analysis of the arguments a few years ago. I’ll have to see if I can’t find it somewhere, but there were many points against the “aberrant version of Homo sapiens” argument.
Off the top of my head, there were morphological similarities between the different sets of remains - remains which have a range of 25,000 years of age - that set them apart from Homo sapiens. IIRC, the teeth, wrist bones, and upper humerus shared some aspects with Homo erectus.
The new paper appears to argue that people with Down Syndrome have diagnostically shorter thigh bones, which would skew the approximate height, but the specimen LB1 was nearly complete - meaning the femur could be compared to the tibia, and specimen LB8 was also nearly complete - if it is missing the femurs, the other bones should provide enough markers for a convincing, if not perfect comparison. The suggestion that the smaller brain case is indicative of Down Syndrome only works if other physical markers are seen as well. Yet, LB1 and LB8 show a distinct lack of chin and forward jaws while Down Syndrome individuals have notably flatter faces than average.
I think the key factors arguing in favor of the existence of Homo floresiensis are:
-
a total of eight individual’s remains were recovered, and while only one possessed a nearly complete skull and femur, the others provided enough osteomorphic markers - including teeth, wrist bones, and tibia - to show common traits not found in any populations of Homo sapiens.
-
the remains have some traits in common with Homo erectus, and proportionally, the brain size matches that species.
-
the difference in stature between H. floresiensis and H. erectus can be explained by insular dwarfism - the tendency of some species in island habitats to evolve into smaller forms.
-
those remains were deposited over the course of 25,000 years.
It’s one thing to say ‘this skeleton shows signs of Down Syndrome’. It’s unlikely but certainly within the realm of possibility. However, to say ‘these eight individuals whose remains vary in age by over 25,000 years all had a random genetic disorder that occurs approximately once every thousand births, and that is the explanation for their height and the small size of their skulls’ . . . that’s wandering into the realm of confabulation.
The part of the article that confused me
Are they saying a just over 4 ft adult height is within the normal in the area?
Maybe they could have finished this study before, you know, claiming it was a new species.
The goddamned creationists will have a field day with this. Not that I pay any attention, but based on people I know repeatedly posting a shitty Facebook video of some fat guy in a car “debunking” evolution, this will be more than enough proof that those durn scientists are making it all up.
N/m
So, I was curious enough that I went looking for the paper. Evolved developmental homeostatis disturbed in LB1 from Flores, Indonesia, denotes Down syndrome and not diagnostic traits of the invalid species Homo floresiensis.
A lot of it is over my head, but here’s what I gleaned:
Someone noticed that the skull from LB1 was asymmetrical. They mention a couple of times that standard bone markers are not available due to how the bones were preserved (that is, not fossilized), but state very firmly that there are asymmetries in the upper face (“exaggerated, reversed frontal and occipital petalia, with marked palatal rotation”) which are reflected in the asymmetrical tooth wear. Facial asymmetry is a symptom of Down syndrome.
They argue that if LB1 were a Homo sapiens of extremely short stature, skull circumference and brain volume are proportionally consistent with what could be expected of an extremely short statured individual with Down syndrome.
They say the skull shows signs of early suture closure (which might have caused the facial asymmetry and is a symptom of DS) but didn’t say what those signs were. They say the skeleton showed signs of hypothyroidism (another symptoms of DS), but didn’t say what those signs were.
They spend more than a page explaining that if LB1 didn’t have such a short femur and if the foot:femur ratio weren’t different from the norm, her height would have been within a standard deviation for the normal range of human populations similar to the ones who currently live in the geographic area.
Then it has a chart of the different traits and symptoms, whether each is present in LB1, the other specimens, and whatever notes are relevant. What becomes clear is that there simply is no way to reach a firm conclusion without another skull or femur to compare to. The traits could be those of a very short individual who also had pronounced Down Syndrome with a bushel full of complications.
Other explanations for the traits are not explored, and evidence that favors the H. floresiensis hypothesis is dismissed. Some of the conclusions drawn from the skull seem very aggressive to me, considering the condition of the remains and the margin for interpretation. And calling a skull brachycephalic when its index is 80 is really, really reaching.
There are populations in the area for which that is within the normal distribution. These can be found throughout Indonesia, the Philippenes an other islands in the area. Consider the Negritos.
As for the OP, I would think the multiple specimens found would undermine it, but I guess we need to wait and see further analysis. I don’t think we need to assume that this particular study is the end of the road for these fossils.
True…but if the study had concluded the opposite, they’d have just taken out the word “not” when quoting it, and had exactly the same field day. Their dishonesty really is that blatant.
Scientific studies are never “finished.” They are always open to new data and new interpretations of existing data.
This controversy is not at all new. Challenges to the species status of Homo floresiensis began almost before the ink was dry on the original paper. There have been previous claims that it was a microcephalic modern human, while other papers have refuted this view.
There’s no reason to believe that this paper settles the issue. It’s just one interpretation. As phouka describes, there is plenty of other evidence that suggests that the original interpretation was correct. Personally, I would like to see a lot more than the current paper has to offer before accepting that H. floresiensis isn’t real.
Creationists don’t need any such studies to conclude that scientists are “making it all up.” There are mountains of proof against creationism, and yet they believe that even the most solid evidence has been made up or misinterpreted by scientists. So this gives creationists exactly zero new support.
Even given such short stature of the fossils, is the very low cranial capacity typical of Down syndrome? I’ve always been under the impression that the physical brain size of DS individuals isn’t significantly different from that of non-DS people.