Homo floresiensis is a small, archaic-looking member of the human family that lived surprisingly recently in the island of Flores. It's perhaps the most enigmatic member of our family; being far smaller, more archaic-looking, and recent than it should be. It's small stature is exceptionally strange, earning it the nickname "hobbit". But for the first time in more than a decade, new hobbit fossils have been found, finally shedding a bit more light on this mysterious species.
These "new" hobbit fossils aren't ostensibly impressive; representing a handful of teeth and jaw. However, that downplays their importance. They clock in at 700,000 years old; more than 10 times the age of previously found fossils on the island!
This ancient age means they could finally shed light on just how the tiny hobbit came to be a big deal in human evolution.
Hobbit fossils' enigmatic evolution
How did such a strange species of human evolve? It's a fascinating mystery people have obsessed over since these fossils were first found more than a decade ago.
Currently there are two main candidates: Homo erectus and Australopithecus. Homo erectus being the first tall-bodied - ironically - member of the human family to stride out of Africa. Australopithecus were their smaller, more ape-like ancestors who - as far as we know - never set foot in Asia.
All of this seems to make Homo erectus look like the obvious candidate for the ancestor of the hobbit. They were living in in the region around the same time; whilst Australopithecus was nowhere close. And sure enough, if you look at the hobbit fossils many support this conclusion. The teeth, cranium and jaws of the hobbit are notably similar to Homo erectus; although with a few unique twists. For instance, the crown of one of their premolars is much more asymmetrical than would be expected. How crazy is that?
However, things get a bit more confusing if you look at the rest of the body. Unfortunately we don't have much to work with here (and these new hobbit fossils don't add much to the picture). But what is preserved is much more Australopithecus-like than would be expected. In particular their wrist seems incredibly archaic; more adapted for a life in the trees than Homo erectus was.
This disagreement between the head and body has led to legitimate debate over exactly who the hobbit evolved from. Nothing like that fake debate over whether or not they were dropped on the head as a child, or whatever silly disease idea is being advocated these days.
Since this new set of hobbit fossils only represents the head, it's unlikely to convince most Australopithecus-as-mummy advocates. There's no body - archaic-like or otherwise - to compare it to. Sure enough, Nature is quoting researchers as claiming that these new fossils simply aren't complete enough to confirm who the hobbit evolved from.
But William Jungers, a palaeoanthropologist at Stony Brook University in New York, says that the fossils are not complete enough to favour the H. erectus origin: "I don't believe these scrappy new dental specimens inform the competing hypotheses for the origin of the species one way or another."
Bones of erectus
Despite being just a bit of skull; some analysis can still be done on these "new" fossils to get a-head of the game. In fact, the skull is the best bit of body to have for such an analysis.
Given teeth are so tough they survive more often than any other part of the body. Which I guess just goes to show how evil coke is. As such, we have a really good idea of how they evolved over time; and what the nasshers of a given species looked like. Now; this isn't a perfect datapoint as teeth can vary within a species. Obviously tooth wear can drastically change their shape, but different populations can have different teeth as well.
Which is part of what makes this new set of finds so important. They come from a site more than 70 km away from the original discoveries of the hobbit. That set of fossils seems mostly consistent with having Homo erectus teeth; despite their more ancient-looking body. This new set of fossils likely represents a different populations, so if they also have Homo erectus- like teeth we can be sure this isn't just a case of intraspecies variation.
And sure enough, we can. The new set of teeth cluster very closely with Homo erectus. This confirms that we really are dealing with an offshoot of Homo erectus here. Their seemingly archaic adaptations may just have been how they adapted to life in a more densely forested environment.
This doesn't seem to have been the only case of evolution in the hobbit. After all, their small size is something unique they evolved. Many prey animals often evolve smaller when on isolated island; compensating for the reduced food they can find. In fact; they weren't the only species to do so. There are also tiny elephants found on their island; smaller than a non-hobbit person.
As an interesting aside, predators often get bigger on islands as they can (no pun intended) dwarf their prey. Given hobbits didn't undergo this change, it might indicate they were prey. On the other hand, one animal on the island which did get big was a species of bird. Could it be that these giant birds hunted the hobbit?
Another interesting piece of evolution in the hobbit took place in their teeth. These "new" hobbit fossils are more than 700,000 years old; compared to the measly 70,000 years old of the previous fossils. Whilst the two groups are broadly similar, the more recent hobbit teeth have a few new developments; suggesting evolution was on-going amongst this species.
Mystery of Sulawesi
However, whilst these fossils might explain one part of how the hobbit evolved; they also create another mystery. These new 700,000 year old hobbit fossils were found with a collection of stone tools.
These Oldowan-style simple flakes are surprisingly similar to tools found on the nearby island of Sulawesi. Could it be that Homo floresiensis didn't even evolve on the island of Flores, from which it gets it's name? The dates sort of line up. We know humans were making tools on Sulawesi before 100,000 years ago. 700 thousand years ago is before then (although that's a big enough margin of error to cause doubt).
However, there is another rather interesting indication that this species really originated in Sulawesi: ocean currents. The more obvious location for where the hobbit might have come from is the larger island of Java, to the west. In fact, Homo erectus fossils have even been found in Java ( the infamous Java man). However, ocean currents flow into the region from the Pacific Ocean (which is north), creating a strong push south that might have easily transported any ocean-going hominins from Sulawesi to Flores.
Given Homo erectus was on Java, if that was the source of the hobbit it seems clear that they evolved in Flores. However, if they actually originated elsewhere this raises the possibility that they could already have been small by the time they got there. But before we get too excited, it's worth noting we're a long way from pinpointing the origin of the hobbit. There aren't any ancient fossils to study on Sulawesi. And of course there's the question of time. Would these currents still have dominated when Homo floresiensis was about? After all, sea levels were a lot lower. It's currently difficult to say (although does seem to be the case).
So, one mystery about the hobbit ends but another is created. This enigmatic branch of humanity continues to surprise everyone involved.
Which is great for me as I get to squeeze more articles out of it.
Summary
New hobbit fossils are ten times older than any we've discovered before, shedding light on the evolution of this enigmatic species. It turns out they're likely descended from Homo erectus; but might not have evolved on the island where all their fossils have been found.
References
A. Brumm et al., "Age and context of the oldest known hominin fossils from Flores," Nature
Kaifu, Y., Kono, R.T., Sutikna, T., Saptomo, E.W., Awe Due, R. and Baba, H., 2015. Descriptions of the dental remains of Homo floresiensis.
G. van den Bergh et al., " Homo floresiensis-like fossils from the early Middle Pleistocene of Flores," Nature
Morwood, M.J. and Jungers, W.L., 2009. Conclusions: implications of the Liang Bua excavations for hominin evolution and biogeography. Journal of Human Evolution, 57(5), pp.640-648.
