"The hobbit" is a weird species of human that lived on an Indonesian island, ~12 kya. It's odd because it's very small and primitive, especially considering it lived so recently.
The peculiar nature of this species (technically called Homo floresiensis) has led to a lot of rather wacky hypotheses about the subject. Like the fact it could be a descendant of Lucy's species.
But by far the most absurd idea is that the hobbit was simply a variant of modern humans. It's claimed disease, genetic defects, or malnutrition turned "normal" humans into these tiny, primitive creatures.
This idea is patently false, having been refuted dozens of times in the decade since the hobbit was discovered. Yet it just won't die. Some scientists continue to argue ( via rather dubious methods) that this was just a human.
Now analysis of the hobbits' teeth have yielded yet more evidence they were a distinct species. Hopefully this takes a big bite out of the claim Homo floresiensis was actually Homo sapiens.
The tale of the hobbits' teeth
This new study examines the teeth of the hobbit. Teeth are a pretty big part of our understanding of evoluton since they're very tough. Enamel ensures they survive for millions of years. In some cases they're all that's left of fossils.
As such palaeoanthropologists have a lot of expertise when it comes to studying fossil teeth. Not only can they figure out which species they belong to, but sometimes even how related those species are. A team of Japanese researchers applied this experience to the teeth of the hobbit, using statistical analyses to compare their teeth to a bunch of other fossil species' (and modern humans).
Since teeth are so often all that's left, they had a huge body of data to compare the hobbits' teeth too. Dozens and dozens of fossil teeth from most relevant hominin species, along with a huge host of modern human teeth from different locations and periods. It's by far the most comprehensive comparison of the hobbit teeth ever performed.
And without a doubt these Japanese researchers demonstrated that the hobbits' teeth were distinctly non-human. The list of the specifics is rather dull and anatomical ( although if you're interested the article is freely available). They include things like the presence of an "assymetric crown" on the lower third premolar; or the fact their molars are relatively large (when compared to each other). And these aren't simply subjective observations either. The statistical analyses confirmed that these are significant differences between the species.
Although these characteristics aren't completely different from modern human teeth (we are still part of the same family after all) they're definitely archaic enough to not be modern human teeth.
Whose your daddy?
This research doesn't just deal with the non-issue of the hobbit being a different species. It also provides some actual new information on Homo floresiensis. Specifically, its ancestry.
Since it was discovered people have been debating just how it got so weird, isolated and small. The most common hypothesis is that it represents a case of island dwarfism. This biological phenomena happens when an animal gets trapped in an environment with fewer resources (as islands are generally small). Forced to adapt, they sacrifice size in order to reduce the resources they need.
It was thought that Homo floresiensis could represent a dwarfed version of a later member of the human family, like Homo erectus. However, some noted that it had many characteristics that were distinctly more primitive than seen in Homo erectus. As such, it might actually be a descendant of an even earlier species.
However, this analysis of their teeth rather poo-poos on that idea as well. Although they noted their teeth were very different to modern humans, they found they were quite similar to Homo erectus. This seems to confirm that these were dwarfed individuals after all. Which is a bit of a downer. I liked to imagine Lucy secretly travelling all the way from her home in Africa to Indonesia.
Milk teeth
But before we begin to digest these results, it's worth noting there are some flaws with this research. Actually, not with the research itself, but with the subject material.
Teeth are a great resource to study because they are preserved in so many different fossils. And they do tend to differ between species. However, teeth can also vary pretty considerably based on the diet of an individual over time. Wear and tear can significantly change the shape of teeth, and thus the results of this sort of analysis.
The researchers did try to take this into account by examining landmarks unlikely to be influenced by such damage. But at the end of the day the fact remains they only had a handful of hobbit teeth to work with. Larger samples can help identify anomalies caused by wear and tear (and thus rule them out). Yet they only had the teeth from two individuals (plus four extra teeth) to work with.
The myriad of differences they found between humans and hobbit teeth confirms that these definitely weren't just humans. But before we start making more specific conclusions about how they were all related I'd like to see a nibble of extra data. Just to be safe.
tl;dr
Examination of the teeth of Homo floresiensis reveals they're very definitely not human. They're most likely a dwarf variant of Homo erectus, although maybe you should take that claim with a bite of skepticisim.References
Boyd, R., & Silk, J. B. (2015). How Humans Evolved. WW Norton & Company, New York.
de Pinillos, M. M., Martinón-Torres, M., Martín-Francés, L., Arsuaga, J. L., & de Castro, J. M. B. (2015). Comparative analysis of the trigonid crests patterns in Homo antecessor molars at the enamel and dentine surfaces. Quaternary International.
Kaifu Y, Kono RT, Sutikna T, Saptomo EW, Jatmiko ., Due Awe R (2015) Unique Dental Morphology of Homo floresiensis and Its Evolutionary Implications. PLoS ONE 10(11): e0141614. doi:10.1371/journal.pone.0141614
Ravosa, M. J., Menegaz, R. A., Scott, J. E., Daegling, D. J., & McAbee, K. R. (2015). Limitations of a morphological criterion of adaptive inference in the fossil record. Biological Reviews.