Apr 25 2017

New Study of The Hobbit

HobbitI have been following the story of Homo floresiensis for the last decade, and it is fascinating. The remains of a diminutive humanoid were found on the island of Fores in Indonesia. The remains date to about 54,000 years ago. The findings immediately sparked debate, with two primary schools of thought emerging.

The first hypothesized that H. foresiensis (nicknamed the Hobbit due to their small size) was a new species of hominin, likely evolve from H. erectus and displaying an example of island dwarfism. The second argued that the remains are not a new species at all and represent a pathological H. sapiens (modern human).

The two groups have argued back and forth in the scientific literature over the years. It is, in fact, a great example of the scientific method in action. Each group brought new evidence and a new perspective to bear, and had the burden of proof to demonstrate their hypothesis. They fought it out with science and evidence.

I and many others sat of the sidelines and watched the epic battle of science. I admit I was rooting for H. floresiensis, but we would all have to listen to the evidence, whatever it showed.

It’s also a good example of the limitations of mainstream science reporting. Each time a study was published, favoring one side of the debate or the other, it was reported as if the debate were finally over and now we know the answer. Instead they should have put that one study into context – this is just another round in an ongoing debate. The fight isn’t really over until one side concedes defeat and a consensus emerges. Even then, new evidence may trump the consensus, but at least we have a consensus rather than a controversy.

The New Study

So, here we go again with a new study claiming to settle the debate. This may do it, because it is the most thorough study to date, but we will have to see how the scientific community responds. The study is by paleoanthropologist Debbie Argue and her colleagues. They examined 133 anatomical data points on the H. floresiensis remains, and compared them to modern humans, H. erectus, and older specimens.

They were essentially testing three hypotheses: H. floresiensis is a pathological human, is most closely related to H. erectus, or is most closely related to an older human lineage from Africa (such as H. habilis). What they found strongly supports the hypothesis that H. floresiensis is most closely related to H. habilis.

They argue that the data rejects the pathological human hypothesis to almost 100%. This is one way to tell which hypothesis in a true controversy has the upper hand. When the data gets more detailed and rigorous, toward which hypothesis does it move. In this case at least these researchers are saying that the more detailed analysis has all but rejected the pathological human hypothesis.

Even more interesting, however, is the fact that the data favors a closer relationship with H. habilis than H. erectus. The reason it was assumed that H. erectus was a likely immediate ancestor is because H. floresiensis was found outside of Africa. The earliest known migration of human ancestors out of Africa was of H. erectus. They were tall, they were hunters, and they used fire. It it thought that this combination of factors made them competitive enough to spread out to Europe and Asia. In fact, as large hunters they would have had to spread out.

H. floresiensis, however, shows numerous primitive features that predate H. erectus. The researchers believe that their connection to our family tree may go back 1.75 million years. This would put their common ancestor with us prior to H. habilis. Essentially they may have shared a common ancestor with H. habilis.

This would further mean that their arrival on Flores was part of an older previously unknown migration of hominins out of Africa, meaning that H. erectus was not the first.

It is fascinating that a remnant of an ancient hominin lineage survived until just 54,000 years ago, or perhaps even more recently. Imagine if a small isolated population of such hominins survived into modern times.

Conclusion

I don’t know if this study will end the controversy over H. floresiensis. We will have to wait and see the reaction of other scientists who hold different opinions. ┬áHaving followed this story, however, my impression is that the needle has been moving steadily in the direction of the conclusion that H. floresiensis is a legitimate hominin species.

This is entirely plausible. Overall, the more evidence we find of human ancestors the more complex the evolutionary bush has become. Humans were a very successful clade showing adaptive radiation, and spread throughout the world. This is generally what we see in successful groups.

We tend to have evolutionary hindsight bias, however. We look back from the perspective of the survivors as if they were inevitable and unique. We still need to purge our evolutionary thinking of this linear bias. The hippus clade was not evolving toward a modern horse, that is just one line that happened to survive. Feathered dinosaurs were not evolving toward modern birds, that is just the surviving clade.

Our human ancestors were not evolving toward us, they were just adapting to their local environment and spreading out as they became more successful and versatile. We are the survivors. However, H. floresiensis were also survivors, up until very recently. H. neanderthalensis were a very successful species. It is still not clear why sapiens ended up dominating. We did interbreed to some extent. It is possible we out-competed them. It is also possible that Neanderthals were better adapted to ice age climates.

Evolution is chaotic and complicated. H. floresiensis is now one more complicated detail in the story of hominin evolution.

 

10 responses so far

10 Responses to “New Study of The Hobbit”

  1. Michael Finfer, MDon 25 Apr 2017 at 7:52 am

    The next question is whether classifying the hobbits as Homo correct? Is Australopithecus more appropriate?

    This will continue to fascinate for many years.

  2. bachfiendon 25 Apr 2017 at 1:48 pm

    Michael,

    I’m not a palaeontologist, but if the illustration is that of a ‘hobbit’ skull, to me it looks like a homo skull not an australopithecus skull. It’s human-like not ape-like, explaining why some think that it’s just a pathological Homo sapiens.

    Perhaps someone more knowledgeable would comment?

    It’s not an unreasonable question. It’s not uncommon for species to be moved from one genus to another.

  3. cepheadon 25 Apr 2017 at 4:01 pm

    In light of these new findings, have we learned anything new about their dietary habits, particularly with regards to the hypothesized “second breakfast”?

  4. bachfiendon 25 Apr 2017 at 4:09 pm

    And do they like smoking pipes?

  5. BillyJoe7on 25 Apr 2017 at 5:32 pm

    And living in cute little houses dug into hillsides?

  6. Michael Finfer, MDon 25 Apr 2017 at 7:27 pm

    Bachfiend, I mentioned that because some paleoantropologists have stated that some parts of those skeletons, especially the foot, are very primitive, Australopithecus-like.

    Hopefully, it will be possibly eventually to extract DNA from one of these specimens. That should settle these issues but will require finding better preserved specimens, something that may or may not happen.

  7. bachfiendon 25 Apr 2017 at 8:36 pm

    Michael,

    I don’t think that there’ll be DNA available to decide one way or another definitely. Preservation of DNA (unlike in the Altai) is unlikely to be adequate in the tropics.

    Just a slight quibble – it’s wrong to use the term ‘primitive’. No feature is ever primitive – they’re adapted for the conditions at the time.

    Has any reputable palaeontologist gone as far as to call the species Australopithecus floresiensis?

  8. N Stephenson 26 Apr 2017 at 9:46 am

    Well, the placement of hominin species into Australopithecus or Homo is more related to suspected behavior than anything else. This has roots in the naming of Homo habilis, which the Leakey team believed was the species responsible for the manufacturer of the Oldowan tools, despite there being fossils for other hominins in the same context (Paranthropus boisei). Prior to that, cranial capacity and a suite of dental features were used to place fossils into one genus or the other.

    Since the Flores hominins are associated with the controlled use of fire, stone tools, and an exodus from Africa (despite their cranial capacity), they are placed in Homo. However secure or appropriate you feel the interpretation, this is the same sort of logic behind the naming of Homo naledi and Australopithecus sediba. Neither is associated with stone tools, but the former is thought to have practiced some sort of burial and significant form of arboreal locomotion, while the other just a significant amount of arboreal locomotion. It is an odd, possibly incorrect, convention, but that is how it generally works in palaeoanthropology.

  9. Sarahon 26 Apr 2017 at 12:05 pm

    I’d be stunned if they were. Like earlier, their skulls are very homo. and one feature does not an australopithecus make.

    It’s not impossible, mind – gigantopithecus ranged as far as Vietnam to our current understanding, so it was never our understanding that no hominims ever left Africa. It would be fascinating if any group of pre-homo hominim survived for any length of time in isolation.

  10. Steven Novellaon 26 Apr 2017 at 3:03 pm

    bach – I have to disagree with you about the word “primitive.” You are simply interpreting the word colloquially rather than technically. You are referring to the definition of – poorly or incompletely developed – as if we were referring to technology.

    Rather, when paleontologists use the term they simply mean that a feature relates to an older common ancestor. There is nothing inherently primitive about a feature, it is all relative.

    For example, if A. afarensis had a particular bony feature that was then lost in the Homo genus, and then we find a new specimen that shares the bony feature with afarensis, that would be a primitive feature, because it links them to a common ancestor that predates Homo. Therefore they cannot have derived from Homo.

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