It’s 10 years since the discovery of Homo floresiensis (aka the “Hobbit”) was announced. The bones – and debate they’ve generated – can tell us a lot about our evolution and the scientists who reconstruct it.
I remember the day well: the 28th of October 2004 is firmly embedded in my memory, when the discovery of Homo floresiensis was announced. And, I readily confess that my first reaction was disbelief.
It was a discovery that flew in the face of 150 years of understanding of human evolution.
I quickly rang my former PhD supervisor, and then mentor and close colleague, the late Alan Thorne at the Australian National University in Canberra, and he expounded similar disquiet.
We wondered and discussed whether some kind of disease or combination of diseases could have been responsible for it’s remarkable anatomy: a rather prophetic discussion with hindsight.
An incredible find
The first skeleton, published in 2004, was dubbed LB1 (Liang Bua cave find No. 1) and included a partial skull with most of the teeth in place, several lower limb bones, hand and wrist bones, some bones of the shoulders, ribs, and elements of the hips.
Through a combination of dating techniques on cave sediments it was estimated to be only about 17,000 years old.
LB1 was a two-footed (bipedal) ape, reconstructed to have stood just over a metre tall, and weighing close to 30 kilograms.
Even more striking, its estimated brain volume was among the smallest ever found in the hominin, or human evolutionary, group at just 380 cubic centimetres: although, this estimate has now been revised up slightly.
In many other respects its face, teeth and limb bones combined features seen in Australopithecus from several million years ago in Africa, features seen in Homo erectusfrom hundreds of thousands of years ago in Indonesia, some anatomical traits like living humans, and a host of bizarre features new to science.
The next year, more bones were described in another article in Nature, this time their age being extended from a fossil bearing unit dating from 95,000-74,000 years old right up to another one aged around 12,000 years old.
For many sceptics, this new evidence was important, for no longer was the Hobbit a single, aberrant, and incomplete skeleton, it had become a long lived population. Yet, there was, and still is, only one skull.
These new fossils, especially the second lower jaw and its teeth, as well as a large number of spinal (vertebrae) and limb bones were similarly enigmatic in their anatomy and resembled the LB1 remains when they could be compared.
A slow conversion
Now, I readily confess that I was slower than many to accept the Homo floresiensis hypothesis; and all descriptions of a new species are just that, scientific hypotheses that require testing.
I never published anything questioning the find, and although a couple journalists and many colleagues did ask my opinion, I declined at that stage to offer one, as advised by Thorne. It was very good advice.
The debate over the finds and their significance got very heated, and sadly, very personal. Long-held animosities began to raise their ugly head in the media, intergenerational squabbles and cultural differences about the role and weight to be given to senior scientists played out publically.
Accusations were made about carelessness in handling the bones. Fingers were pointed and individuals accused of unauthorised and unethical access to the remains.
In 2004, the first of a number of studies criticising the “new species” hypothesis was published by Thorne and Maciej Henneberg of the University of Adelaide, alongside of a response from Peter Brown of the University of New England, and others who had described them.
This article began the assault by a group of scientists suggesting the Liang Bua remains, chiefly LB1, were simply from a diseased modern human, perhaps even an indigenous person from the island of Flores, with short-statured people living there today.
My initial impression had been taken much further, but I was very uneasy. Evidence was quickly garnered by Thorne, Henneberg, Teuku Jacob, Etty Indriati, Charles Oxnard and other scientists from Australia, Indonesia, the United States and other places for pathology as the cause of the features others had come to regard as indicative of a new species.
In fact, over the last decade no less than eight diseases or syndromes have been suggested as possible explanations for the unusual features of LB1, to account for its resemblance to primitive hominins.
Yet, I began to have serious doubts. I had spent the first 10 years of my career working on early hominin fossils in Africa, and had in fact described with the late Phillip Tobias the most complete skull belonging to the earliest species of Homo from South Africa, as well as other early fossils from that country; and had worked on very ancient bones in Kenya as well.
The brain surface anatomy of LB1 was also studied on a virtual model made from CT-scans by Dean Falk and her team, comprehensive examination of the shoulder and wrist bones occurred, and then the foot bones were studied in detail.
All of the evidence was pointing to a very, very primitive brain and skeleton: one like that seen in our ancestors hundreds of thousands, if not millions, of years ago.
By 2007, I became unconvinced that a diseased Homo sapiens could end up resembling primitive hominins in so many ways. And, I told a journalist so, for the first time offering my opinion about the finds: I found the new species hypothesis convincing.
A small brain through arrested brain growth is one thing, short stature another, but the striking resemblance of so many features from across the skeleton would be too much of a coincidence and require far too much ad hoc explaining to ring true, for me anyway.
Clearly others disagreed, and continue to do so, the debate about which disease may have caused such gross disfigurement, nay evolutionary reversion, continues, the latest candidate being Down syndrome published in 2014 by Henneberg and co-workers.
The bigger picture
While it’s true that palaeoanthropology – the science of human evolution – has a history of sometimes rather extraordinary claims, and even downright frauds such as the Piltdown Man, I think the Hobbit debate has by historical standards been rather unusual.
For a start, it has lacked a larger than life colonial figure at the centre of the discovery: historically we have often seen eccentric and exuberant characters like Eugene Dubois, Raymond Dart, Louis Leakey or Robert Broom taking on the world to show how they have more or less single handedly solved a key riddle of human evolution; and in a place far from the centres of European colonial power.
While Homo floresiensis has had its enthusiastic public champions, including the late Michael Morwood, Australian co-leader of the project that discovered it, much of the ego and flamboyancy of earlier eras has been lacking, although the conviction certainly hasn’t been.
Also different this time has been the way a number of leading international scholars rallied around to support the find from its first announcement.
I guess one the key differences has been that the scientific manuscripts describing the Liang Bua finds were anonymously reviewed by senior colleagues prior to their acceptance for publication in Nature.
When Dart described Australopithecus and the Leakeys discovered Zinjanthropus this top-of-the-pops science journal didn’t require such rigorous review prior to articles hitting the printing presses the Hobbit find was subjected to. Instead, discussion and review of the science played out through correspondences sent to Nature.
Ten years on since the announcement of Homo floresiensis we are scarcely any closer to understanding the origins and evolutionary relationships of this very enigmatic species.
While its always a precarious thing to try to second guess where the “silent majority” stands on any issue, I think its fair to say that a majority of specialists accept that the remains represent a new species of a very primitive human relative.
I also think history will show that the Hobbit stands as one of the most surprising, challenging and important discoveries made in the 150 or so year history of palaeoanthropology: up there with Dubois’ Pithecanthropus, Black’s Sinanthropus, Dart’s Australopithecus and the Leakey’s Zinjanthropus.
Image: Modified image from Wikimedia Commons (Ryan Somma). First published in October 2014 and by ABC Science.