Indiana Bones, the Melbourne archaeology students and the fossil 'jigsaw puzzle' that wowed the world

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Indiana Bones, the Melbourne archaeology students and the fossil 'jigsaw puzzle' that wowed the world

Gluing together the delicate fragments of a fossilised skull in South Africa – and trying hard not to sneeze – two Melbourne students were astonished at what they saw. Could it be a direct ancestor from two million years ago?

By Jane Cadzow

Jesse Martin wondered briefly whether he was up to the challenge. The table in front of him was covered in pieces of fossilised cranial bone. He knew they came from the skull of an ancient creature. But which ancient creature? That was the mystery he needed to solve. “There were more than a hundred tiny fragments, so it was quite hard to get a sense of what it could be,” he says. “The biggest part would have been no bigger than a 50-cent piece. The smallest part would be smaller than your little fingernail.”

Homo erectus cranium. The remains of a hominin, any hominin, is considered a thrilling find.

Homo erectus cranium. The remains of a hominin, any hominin, is considered a thrilling find.

It was July 2015. Martin, then a second-year archaeology student at Melbourne’s La Trobe University, had gone to South Africa to attend the university’s annual field school at Drimolen, an excavation site 40 kilometres north of Johannesburg. While he was there, the fossil fragments were unearthed. At first they were presumed to have come from a baboon, but a quick effort to rejoin a few of the pieces on site made that seem less likely. The curvature of the cranium wasn’t right.

“Some people thought, ‘Well, it’s probably a monkey of some kind,’ ” Martin says. “Others thought it might be an extinct big cat.” Still others were optimistic it was a hominin – that is, a member of the tribe of primates that incorporates early relatives of humans, including those in our own genus, Homo. Martin offered to have a crack at clearing up the confusion. “I said, ‘Well, look, I’ll try to put it together and see what we have.’ ”

With his girlfriend and fellow student, Angeline Leece, he carefully packed the pieces into plastic containers lined with cotton wool and drove to Johannesburg. The aim, he says, was to take apart the glued section, clean everything properly and “start from, pardon the pun, bare bones”. The process was made trickier by the fossils’ fragility: some were little more than translucent flakes. “We used a tiny paint brush and acetone – which is nail-polish remover – to loosen the sediment. Then I sucked it up and blew it off with a straw.”

Archaeology students Angeline Leece and Jesse Martin with the reconstructed skull, put together from more than a hundred fragments.

Archaeology students Angeline Leece and Jesse Martin with the reconstructed skull, put together from more than a hundred fragments.

After all traces of soil were removed, Martin began attempting to connect the pieces, an exercise he likens to doing a three-dimensional jigsaw puzzle with no reference picture and who-knows-how -many bits missing. Despite the mind-bending degree of difficulty, he felt fortunate. “It is rare that people who are students or early-career researchers get the opportunity to be in the same room as these fossils, never mind work with them.” I ask whether it was the first time he had reconstructed a skull. “It was the first time I’d reconstructed anything at all,” he says cheerfully.

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For a couple of weeks, both Martin and Leece devoted almost every waking moment to the project. They spent hour after hour sitting perfectly still, afraid to talk or take a deep breath – and terrified of sneezing – as they held delicate fragments in place and waited for the acrylic resin they were using as adhesive to slowly set. “It was something that could test a relationship,” says Martin, who had been dating Leece for only six months, “but for us it was good.” The job over, they stood back and gazed in awe. Though the cranium was incomplete, enough of it was there for the couple to know who had owned it. At least, they thought they knew: Homo erectus, which Leece explains to me is “probably the oldest species that we can confidently say is our direct ancestor. Once you get older than that, it gets a bit fuzzy.” If they were right about it being Homo erectus, the implications were huge.

The University of Witwatersrand in Johannesburg, where Leece and Martin had based themselves, is home to one of the world’s finest collections of primate and hominin fossils. Comparing the skull with a range of specimens increased their confidence that their hunch was well founded. Even so, they kept the information to themselves for a while, turning it over in their minds, worrying they were making a rookie mistake. “You’re a student and you’re= going to get on the phone to senior colleagues and contradict 60 years of palaeoanthropological and fossil evidence from Africa,” says Martin. In those circumstances, you want to be on firm ground. “So we took a couple of days to convince ourselves we weren’t missing something horrendously obvious. We were keenly aware of our inexperience.”

Leece remembers their excitement when they decided it was time to stop agonising and make the call. “We finally came to terms with what we were looking at, and what it meant,” she says. “It was going to rewrite the story of human origins.”

The man they rang was Professor Andy Herries, the director of the Drimolen field school and head of La Trobe University’s department of archaeology and history. Herries, 44, is a lively character who tells me his career path was never really in doubt: aged only three, he asked his grandmother for a hammer so he could break up rocks in the garden in search of fossils. As an older kid, Herries adored Raiders of the Lost Ark and the rest of the action-adventure movie series in which Harrison Ford played the fictional archaeology professor, Dr Henry “Indiana” Jones. “They remain some of my favourite films to watch,” he says. “Other archaeologists get very bent out of shape about it, going on about how it’s got nothing to do with archaeology and it’s basically glorified grave robbing, but I just think, ‘God, that’s a bit overly serious, isn’t it?’ ”

Andy Herries, head of La Trobe University’s department of archaeology, director of the Drimolen field school and Indiana Jones fan: when he was aged only three, he asked his grandmother for a hammer so he could break up rocks in the garden in search of fossils.

Andy Herries, head of La Trobe University’s department of archaeology, director of the Drimolen field school and Indiana Jones fan: when he was aged only three, he asked his grandmother for a hammer so he could break up rocks in the garden in search of fossils.

Herries specialises in palaeoanthropology – the study of the origins and development of early humans – as well as geochronology, which is the science of ordering events in the earth’s history by dating rocks, sediments and fossils. He says he was sure from the start that the skull pieces dug up at Drimolen came from a member of the extended human family. Hominin fossils – mainly teeth – had previously been found at the site. A hominin, any hominin, was a thrilling find. But neither Herries nor his colleagues at the field school were prepared for Martin’s and Leece’s announcement on the phone that the cranium was Homo erectus. Says Leece: “I don’t think they believed us. Early the next morning, they drove into town from the site to have a look at it.”

“We finally came to terms with what we were looking at, and what it meant. It was going to rewrite the story of human origins.”

Archaeology student Angeline Leece.
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The scepticism was understandable. Despite decades of intensive archaeological exploration, no fossil identified as Homo erectus (which means “upright man”) had been found in southern Africa. And according to preliminary dating at the dig site, the Drimolen skull was two million years old. That would make it the oldest Homo erectus fossil ever identified – by a margin of 200,000 years – and a priceless palaeoanthropological treasure. “Everyone wants to find the first appearance of us,” says Martin, “and that’s always been loosely interpreted as whatever the earliest Homo erectus is.”

Our species, Homo sapiens (“wise man”), has little in common with many of our long-lost cousins in the hominin clan. Take four-million-year-old Ardipithecus ramidus, which had a brain the size of a chimpanzee’s, long powerful arms and a grasping big toe that helped it climb up trunks and swing through forest canopies when it wasn’t lumbering along on the ground. Yes, the species has a perch somewhere in the branches of the human family tree, but as its discoverer, US palaeoanthropologist Tim White, has said, “You wouldn’t invite Ardipithecus ramidus to dinner.”

Homo erectus might not be the perfect guest, either – you certainly couldn’t count on sparkling repartee – but at least it would be recognisable as a relative. It had a larger brain than any previous primate, body proportions similar to ours and an easy two-legged gait. The first Homo species to leave Africa, it is believed to have made the first hand axes, hunted in co-operative groups and cared for old and sick individuals.

Homo erectus was the beginning of something new – “the beginning of what it means to be human,” says Herries, who was delighted to see that the skull pieced together by Martin and Leece had the species’ distinctively shaped braincase. That the case was on the small side could probably be explained: the cranial bones hadn’t finished fusing, which indicated they came from a young child whose brain was still growing. And as this was by far the earliest known Homo erectus specimen, its brain could reasonably be expected to be smaller than that of later examples.

The field school, which runs in winter, was winding up for the year, but Herries kept digging. Not far from the spot that yielded the original fossil trove, he uncovered another piece, this one about two centimetres long and one centimetre across. It was a wormian bone, which – in modern humans, too – can occur within skull joints, and it proved to be a key piece of the puzzle. “It actually joined the whole back of the head together,” Martin says. “We were able to slot it right into place and go, ‘Ah, okay, now we have a cranium!’ ”

The following spring, Martin returned to South Africa from Melbourne. He says he spent six weeks sifting through 400 bags of fossils fragments found at the dig site – “everything that had been excavated from that area in the last 10 years”. It paid off. A little bag labelled “tortoise carapace” contained two pieces of fossilised tortoise shell – “but also one big chunk of Homo erectus cranium”. Martin knows that sounds like a serious filing error. “But tortoise carapace can look a lot like cranial bone, it really can.”

The dig site in Drimolen, about 40 kilometres north of Johannesburg, where the fossil fragments were unearthed.

The dig site in Drimolen, about 40 kilometres north of Johannesburg, where the fossil fragments were unearthed.

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Everyone involved in the project was sworn to secrecy. “Some select people were brought into the loop,” says Justin Adams, senior lecturer in anatomy and developmental biology at Monash University in Melbourne. Adams, a long-time colleague of Herries, took a replica of the cranium – created with a 3-D printer – to show Bill Kimbel, director of the Institute of Human Origins at Arizona State University and an internationally respected authority on hominin anatomy. Adams says Kimbel needed no convincing that the Australians were on the right track: “I drop the specimen in his lap, he looks at it and says, ‘Yep.’ ”

Nevertheless, painstaking laboratory work was required to confirm both the classification of the skull and its age. Among the dating techniques Herries used was palaeomagnetic analysis, the study of past variations in the direction of the earth’s magnetic field, as recorded in rocks. This indicated that the geological stratum in which the cranium was found had solidified almost 100,000 years before a reversal in the earth’s magnetic field about 1.95 million years ago.

Analysis of ancient DNA preserved in fossils has revolutionised palaeoanthropology – in 2010, scientists identified an entirely new species by extracting genetic information from a finger bone more than 50,000 years old found in a cave in Siberia – but DNA has a limited shelf life, and the Drimolen skull was well past the expiry date. The various other methods used to study it took time, and the discovery was kept under wraps until April this year, when a peer-reviewed paper written by Herries and his team was published in the US academic journal Science. Almost five years after the fossil pieces came out of the ground, the skull made news around the world. On Herries’ Twitter feed, he posted a picture of himself excavating in South Africa in the kind of headwear favoured by Harrison Ford. “With that hat,” someone tweeted, “you are Indiana Bones.”

When I contact Herries soon after the paper’s publication, he is enjoying being able to talk about the skull at last, but bracing for the reaction from the palaeoanthropological community: “When we said, ‘This is Homo erectus,’ we didn’t know whether people were going to agree with us or go, ‘You’re crazy.’ ” I ask whether there is a genuine chance of a hostile response. “Oh yeah, definitely,” he says with a grim laugh.

Who are we? How did we get here? In studying humankind’s emergence from the primeval mist, palaeoanthropologists seek answers to big and fundamental questions. But the high-mindedness of the pursuit doesn’t necessarily translate to pleasantness in their dealings with one another. The field is famous for petty jealousies, bitter rivalries and simmering feuds. The distinguished American evolutionary anthropologist Dean Falk tells me she has been at conferences where discussions have descended into shouting matches and colleagues have come close to fisticuffs.

“I don’t know if butterfly experts argue with each other,” Falk says, but she doubts their disputes are as acrimonious as those of palaeoanthropologists.

At Monash University, Justin Adams suspects infighting occurs in many branches of scientific endeavour, though he gets the impression people who trace the human family tree for a living are inclined to clash more heatedly than most. Human evolution is a subject that arouses strong emotions. Also, “there’s a particular breed who ends up in palaeoanthropology”, Adams says. “There are huge egos associated with this.”

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In Bones of Contention: Controversies in the Search for Human Origins, British science writer Roger Lewin suggests the tone was set by the Dutch anatomist Eugène Dubois, who in the 1890s found remains of Homo erectus (which he called Pithecanthropus erectus) on the island of Java. The specimen, which became known as Java Man, brought out a snarky streak in Dubois. “It was his discovery, his creation, his exclusive possession; on this point he was as unaccountable as a jealous lover,” noted an observer quoted in Lewin’s book. “Anyone who disagreed with his interpretations of Pithecanthropus was his personal enemy.”

There’s a lot of politics in the field and often not a lot of science … People cling to their pet ideas regardless. And that can play out in some quite nasty ways.

University of NSW palaeoanthropologist Darren Curnoe.

Another pioneer known for his pugnacity was Louis Leakey, the Kenyan-born founder of a palaeoanthropological dynasty now into its third generation of fossil hunting. The late US primate palaeontologist Elwyn Simons summed up Leakey’s attitude this way: “The fossils I find are the important ones and are on the direct line to man, preferably bearing names I have coined, whereas the fossils you find are of lesser importance and are all on side branches of the tree.”

Talking up your own work while playing down the value of others’ has become something of a tradition in the profession, says University of NSW palaeoanthropologist Darren Curnoe, who hopes an excavation he is conducting in Borneo will provide clues to when Homo sapiens first arrived in south-east Asia. Part of the problem, it seems to Curnoe, is that palaeoanthropologists are pitted against one another in competition for funding for research and excavation. Another cause of tension: the limited amount of material available to study. Says Angeline Leece: “The entire human fossil record could fit on the back of a ute.” Curnoe demurs: “I think there are a few more than that. Maybe a couple of ute loads.”

Roger Lewin describes palaeoanthropology as a science that is “short on data and long on opinion”. Because of the scarcity of hard evidence of how humans evolved, the temptation is to fill in the gaps with educated guesswork. “When we don’t have much data and we’re using a lot of imagination, we call it a ‘scenario’,” Curnoe says wryly. “That’s code for, ‘We’re largely making it up’.” He adds that even when evidence emerges that exposes flaws in their hypotheses, palaeoanthropologists can be reluctant to change their thinking: “There’s a lot of politics in the field and often not a lot of science, to be quite frank with you. People cling to their pet ideas regardless. And that can play out in some quite nasty ways.”

No one knew this better than Raymond Dart, the Australian who was the first person to identify the fossil of an early human ancestor in Africa. Born in Brisbane in 1893, Dart graduated from the University of Queensland with first-class honours in biology before moving to Sydney to study medicine. At only 29, he was appointed professor of anatomy at the University of Witwatersrand. The following year, he was sent a crate of primate fossils that had been found at a quarry at Taung, in central South Africa. Most were from baboons, but Dart’s attention was caught by a skull with a flatter face and smaller teeth than the rest. The braincase, though small, seemed to Dart to have human-like aspects. The placement of the opening where the spinal cord left the skull suggested that the creature’s head balanced atop its vertebral column, which in turn indicated it had walked on two legs.

In a paper published in 1925 in the British journal Nature, Dart named it Australopithecus africanus (“southern ape from Africa”) and declared it “an extinct link between man and his simian ancestor”. Newspapers ran sensational “missing link” headlines but the scientific establishment was unimpressed, even scornful. As Matt Cartmill, professor of anthropology at Boston University, puts it, “Most scientists looked at its diminutive braincase, murmured ‘ape’, and shoved it off to a side branch of our family tree.”

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The young Australian’s proposal simply didn’t fit with prevailing beliefs. In the 1920s, the birthplace of humankind was understood to be in Asia or Europe, not Africa. The consensus was that the brain had enlarged early in human evolution and that walking upright came later, so Dart’s suggestion that we were descended from a small-brained bipedal creature was resoundingly rejected. “Preposterous,” sniffed the eminent British anthropologist Arthur Keith, to whom the gold standard in ancestor fossils was a skull with a large braincase that had been found in 1912 in a gravel pit near the English town of Piltdown.

Like Eugène Dubois before him, Dart took his fossil on tour in an attempt to persuade colleagues of its importance. (Each expedition nearly ended in tears. Dean Falk reports in her 2011 book, The Fossil Chronicles, that Dubois left a suitcase containing Java Man underneath a table in a Paris cafe in 1895. Dart’s wife left a box containing the Taung skull in a taxi in London in 1931.) When more Australopithecus fossils were dug up in South Africa in the 1930s, some of Dart’s critics begin to reconsider their position. His final vindication came in 1953, when so-called Piltdown Man was proven to be a fake, created from pieces of a modern human cranium and an orang-utan’s jaw.

Dart was by all accounts an unorthodox and charismatic character: when he died aged 95 in 1988, his obituary in The New York Times said former students remembered him as an animated lecturer who dangled from ceiling pipes to show how apes moved. His upending of conventional wisdom about human origins has come to be regarded as one of the major scientific breakthroughs of the 20th century. “He paved the way for our understanding that Africa is the original homeland of all humanity,” Andy Herries says.

Dart’s fossil, like the find at Drimolen, was the skull of an infant. The Taung Child, as it is known, is displayed in a bullet-proof glass case in the University of Witwatersrand’s fossil vault, the climate-controlled room where Jesse Martin and Angeline Leece rebuilt the Drimolen cranium. “A lot of the specimens are away in drawers and on shelves,” says Leece, “but he is there in the centre of the room. You’re working away and he’s sitting just over your shoulder, looking at you.”

"I thought, 'Wow! I’ve found a fossil.’ I was on cloud nine. Natural euphoria. Just couldn’t believe it!”

Then second-year archaeology student, Richard Curtis.

Leece, who grew up in the US and went to university in New York, says she knew from the first lecture on human origins she attended that she had found her calling: “I went straight from the lecture to the professor’s office and I banged on the door and said, ‘All right, this is what I’m going to do for the rest of my life.’ ” Such decisiveness is unusual, says Herries, who often detects wistfulness when new acquaintances learn he is a professor of archaeology. “The number of people who say, ‘Archaeology! That’s what I really wanted to do but I didn’t think there was a career in it.’ Or ‘I just wasn’t brave enough to do it.’ ”

Martin is one who prevaricated. “I’d always been interested in archaeology and human evolution, since I was a kid,” he says. But when he finished high school, he decided the sensible thing to do was study law. Not until he was in his late 20s and working as an adviser to a Labor member of Victorian state parliament did he resolve to throw caution to the wind and enrol in La Trobe’s archaeology course. He imagines the move struck some as capricious – “the middle-class equivalent of joining the circus” – but he hasn’t regretted it for a second. “I get to spend my entire professional life on the quest for knowledge of our origins. I think that’s an enormous privilege.”

For Martin, now 35, and Leece, 28, who married last year, working on the Drimolen skull has been both career-defining and life-enhancing. Martin says he finds it difficult to convey to anyone who isn’t a palaeoanthropologist how exhilarated he and Leece felt when, alone with the freshly reconstructed skull, they realised they had on their hands a discovery that pushed back by 200,000 years the appearance of Homo erectus, effectively changing the date of the dawn of humanity. “I guess it would be the equivalent of working in astrophysics and discovering a planet that you could be pretty confident had life on it,” he says.

Richard Curtis was a second-year archaeology student when he unearthed the cranial fragments that Martin and Leece put together. Now re-dating the Taung Child for his PhD, Curtis remembers his elation when he started extracting the pieces: “I thought, 'Wow! I’ve found a fossil.’ ” At that point, he and everyone else thought they came from the skull of a baboon. Curtis was back in Melbourne when he got word that it was probably a two-million-year-old Homo erectus.

 Richard Curtis, then a second-year archaeology student, excavated the fragments that made up the cranium. At the time, he and others thought they belonged to a baboon.

Richard Curtis, then a second-year archaeology student, excavated the fragments that made up the cranium. At the time, he and others thought they belonged to a baboon.

“I was on cloud nine. Natural euphoria. Just couldn’t believe it!”

In the Science paper, Herries and his team slightly hedged their bets, referring to the cranium as having “clear affinities with Homo erectus”. As Herries anticipated, some palaeoanthropologists have questioned the claim, but on the whole the reception has been positive. “I think they have made a strong case for the oldest Homo erectus in Africa and, in fact, the world,” leading American fossil-hunter Lee Berger told National Geographic. In any case, Herries sees classification of the skull as a work in progress. “We’re doing some other studies on it which we hope will further strengthen our case,” he says.

“All sciences are odd in some way,” says Boston University’s Matt Cartmill, “but palaeoanthropology is one of the oddest.” A former president of the American Association of Physical Anthropologists, Cartmill means that studying how humans came into existence is of little practical use: it doesn’t change the way we are, or even help us to understand ourselves. “If it was proved tomorrow we were descended from cottontail rabbits instead of monkeys, we’d still prefer bananas to clover as an ingredient in pie,” he says. “If you want to know what humans are like, you look at humans. You don’t look at their ancestors.” That he and others look intently at our ancestors anyway he ascribes to a very human characteristic: curiosity. “We want to know where we came from.”

Monash University’s Justin Adams argues that there are important lessons to be learnt from the past. It is salutary to be reminded that Homo sapiens is the latest in a very long line of hominins to have roamed the Earth. “Really, our species is Johnny-come-lately in this larger story,” says Adams, whose own curiosity about human origins dates from boyhood (as he vividly recalls, it was piqued by a hologram of the Taung Child on the cover of a 1985 issue of National Geographic).

Homo erectus, which we now think was living in southern Africa two million years ago, was still in existence on Java about 100,000 years ago. That is a span of 1.9 million years – a record we will be a long time chasing. The oldest fossils of Homo sapiens, found in Morocco, date from about 300,000 years ago.

To Adams, these numbers put things into perspective, in particular the need to take care of our environment. “We are united as a single species,” he says. “And it’s a species that has overcome incredible odds to get where it is. But we are just as prone to extinction as any other organism ever has been. We’re part of a continuous arc of life on this planet. And I just would hope that would drive a bit of a reflection.”

Andy Herries is pleased to report that the Drimolen skull will join the Taung Child in the University of Witwatersrand’s fossil vault. He is struck by the fact that these two Australian-found specimens were the same age when they died. “Raymond Dart found a three-year-old that ultimately changed our understanding of who we are and where we came from,” Herries says. “Nearly a hundred years later, we found a three-year-old that shows the origins of Homo erectus. And now they’re going to sit there in the vault together, the two three-year-olds. I just think that’s very cool."

To read more from Good Weekend magazine, visit our page at The Sydney Morning Herald, The Age and Brisbane Times.

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