Wallacea: Stepping Stones between Supercontinents

Bali as seen from Lombok

Bali as seen from Lombok

Brochure I produced for the 150th anniversary of Wallace's journey to Indonesia

If you think a journey from Bali to Lombok feels farther than it is, join the club. Back in 1856, a British naturalist made the same observation. His name was Alfred Russel Wallace, and the biological rift between these twin neighboring isles is now known as “Wallace’s Line”.

“In this Archipelago,” Wallace wrote home, “there are two distinct faunas rigidly circumscribed, which differ as much as those of South America and Africa, and more than those of Europe and North America: yet there is nothing on the map or on the face of the islands to mark their limits.”

Wallace discovered the Bali-Lombok division—along with more than a thousand new species and a working theory of evolution—by luck. It helped, of course, that he traversed some 14,000 miles through what is now Indonesia pinning and pickling, tagging and bagging some 125,660 specimens of natural history.

Wallace on chasing butterflies

Roughing it for eight years, Wallace might have been Asia’s first ecotourist. He settled comfortably into huts where we now bunk up at losmen. He hired indigenous guides, treating them with a respect nearly unheard of at the height of the British Empire. And he traveled by all means of local conveyance—cargo ships, dugout canoes, a Moluccan prahu and a treacherous but endearing Bugis schooner. The very unreliability of the transport offered him great serendipity:

“Having been unable to find a vessel to Macassar, I took passage to Lombok, where I was assured I should easily reach my destination. By this delay, which seemed at the time a misfortune, I was able to make some very interesting collections in Bali and Lombok, two islands which I should never have otherwise seen. I was thus enabled to determine the exact boundary between two of the primary zoological regions, the Oriental and the Australian.”

Endemic Seram Cockatoo

Endemic Seram Cockatoo

On Lombok, it was the cockatoos that first caught Wallace’s eye. “This is the most westerly point on the globe where any of the family are to be found,” he noted. He also spotted honey-suckers and Megapode mound-maker birds “here first met with on the traveler’s journey eastward.” Bali’s barbets, fruit-thrushes and woodpeckers, meanwhile, were nowhere to be seen. Nor were there any of the tigers or rhinos known from the western islands of the archipelago. Further years of observation led Wallace to sum up “…we shall find that all the islands from Celebes (Sulawesi) and Lombok eastward exhibit almost as close a resemblance to Australia and New Guinea as the Western Islands do to Asia.”

Tarsier - a primitive primate of Sulawesi

Indeed, there could be no stranger neighbors than Asia and Australia. As Wallace explained, “it is well known that the natural productions of Australia differ from those of Asia more than those of any of the four ancient quarters of the world differ from each other.” Wallace had no way to know how ancient these quarters were, or where they had all come from. But our modern understanding of continental drift suggests that Indonesia is in fact the reunion site of long-lost supercontinents.

It all started back in the Mesozoic era, some 150 million years ago, when Pangea, the mother of all supercontinents, split in two. Laurasia (today’s North America and Eurasia) headed north and Gondwanaland (South America, Africa, Antarctica and Australia) ventured south. Each took their own share of animals: dinosaurs, most notoriously, but also some newfangled creatures—early mammals, followed soon after by birds.

Marsupial cuscus, Seram Island

By the curtain call of the Mesozoic (65 million years ago), dinosaurs were down for the count and mammals had split into rival factions. Modern placental mammals had old-fashioned, pouch-bearing marsupials on the run. Up in Laurasia, where the placentals got their start, marsupials were squeezed out by 30 million BC, save for a few crafty possums. But down in Gondwanaland, the marsupials ruled the roost. Only a smattering of placentals had clambered aboard the drifting continent, now breaking up yet further. Placentals stood no chance in Antarctica when it froze solid 14 million years ago. And in South America the mammal wars got totally out of hand—placental sloths and armadillos grew as big as tanks to fend off pouch-bearing “wolves”, “bears” and “saber-toothed cats”. But even those marsupial beasts were doomed 3 million years ago when South America slammed back into North America and its armies of real bears, wolves and cats.

Komodo Dragon

This Komodo dragon would have looked wimpy next to a fossil cousin in Australia that measured twice his length.

Which left Australia as last the outpost for kangaroos, koalas and other keepers of the pouch. Modern mammals never made it that far—save one or two. So today, watching this old chunk of Gondwanaland inch closer to Laurasia is like witnessing alien worlds on a collision course. Strange creatures now intermingle along the stepping stone islands of Nusa Tenggara, Sulawesi and Maluku—a mixing zone known as Wallacea.

Lesser Bird of Paradise

Lesser Bird of Paradise, Papua

Three curious features distinguish Wallacea:

First, you find endemics—species living on one island and nowhere else on Earth. (Sulawesi boasts 88 unique birds and 82 unique mammals.)

Second, you find mad experiments in evolution. The babirusa, a primeval pig with tusks erupting through its nose, begs the question “Why?”

Third, you find an “island effect”: a trend for animals to be oddly big or small. No where is this more famous than on Flores and Komodo islands. There, fearsome lizards the size of “dragons” inspired the film King Kong. And just thousands of years ago, Flores was prowled by dog-sized rats, cow-sized elephants and people no taller than five-year-olds. Smaller, in fact, than Tolkien’s hobbits, which inspired the nickname for a new fossil human species discovered in 2003.

Wallace, himself, might have been shocked to find that 150 years after his passage, such startling discoveries await among the islands now bearing his name. At this rate, there must be plenty more on the horizon. [END]

Archaeologist Thomas Sutikna examines the Homo floresiensis skeleton that he and his team excavated from Flores in 2003

Archaeologist Thomas Sutikna examines the skeleton of Homo floresiensis that he and his team discovered on the island of Flores in 2003. What other "Lost Worlds" remain to be found in Wallacea?

Wallace on new discoveries

Wallace brochure

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Wallacea: Stepping Stones Between Supercontinents, © Djuna Ivereigh, is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported License. Excerpts may be reproduced with a credit to DjunaPix Indonesia Photography, linked to http://blog.djunapix.com/2010/05/wild/wallacea-supercontinents.

Bones of Contention

Bones of Contention was published in Australia's leading science mag, COSMOS

Bones of Contention was published in Australia's leading science mag, COSMOS

“It’s just another day for us,” Thomas Sutikna tells me, boarding a beat-up minibus bound for Middle Earth. He and his team from the Indonesian Center for Archaeology spend their days hunting “hobbits”— extinct, meter-high humans whose remains they discovered in Liang Bua cave on the remote island of Flores in eastern Indonesia. The only thing different about this day is that Sutikna and crew will have 40-some experts peering over their shoulders and into their digs, debating if and how their work should rewrite what it means to be human.

Since the announcement of the new hominid species Homo floresiensis in October 2004, scientists have argued about the implications of a few handfuls of tiny bones. A majority of researchers welcome the Flores fossils as a new species of human. They embrace the view that we are not alone, at least not recently, and that the hallmarks of humanity—big brains atop long legs—stand to be revised. A vocal minority, meanwhile, reject the new species. They say the Flores fossil is one of us, a modern Homo sapiens, albeit diseased and deformed.

The debate got personal at end-2004 when emeritus Professor Teuku Jacob from Indonesia’s Gadjah Mada University borrowed the Liang Bua bones from the Center for Archaeology and debunked Homo floresiensis in the press. Australian Professor Mike Morwood, a partner on the Liang Bua discovery, cried foul on an institutional agreement regarding management of the bones. The brouhaha degraded into “a level of shouting and name-calling that you do not often hear in Indonesia,” Morwood would later report. Most distressing, however, was that the bones were returned to the Center for Archaeology scarred, broken and clumsily repaired. A member of Jacob’s lab confessed that the damage was the result of botched efforts to cast the crumbly remains.

Political fallout led to closure of the Liang Bua dig site for two years. But 2007 has seen a flurry of renewed activity in and around the cave. Sutikna and Morwood returned for their fifth season of excavations while Jacob sent a team to size up local pygmies, claiming they’re the living descendants of hobbits. And after that, Jacob organized an international symposium on paleoanthropology that focused on Flores and climaxed with a field trip to the cave.

Few scientific arenas are as contentious as paleoanthropology—a field plagued by fewer fossils than there are people who study them. Naturally I wondered what would happen when rivals in the hobbit wars converged on Liang Bua. Would researchers compromise? Or convert? And most importantly, would they behave? I tagged along to find out and to get the big picture on the little people of Flores.

Thomas Sutikna sits in a hotel room in Ruteng, his base camp/paleo lab for the Liang Bua dig. A table is stocked with tools of the trade—dental picks, tinctures, toilet paper to wrap fragile specimens. In one corner, boxes overflow with the dusty remains of beaver-sized rats, pygmy Stegodon (an extinct relative of elephants) and a few hundred stone tools awaiting entry in a database. In another corner sits a suitcase that looks overdue for retirement.

“We have a big story with that,” Sutikna explains. It was the suitcase that carried “LB1”, the type specimen of Homo floresiensis, out of Flores and back to his lab in Jakarta. His colleague Wahyu Saptomo joins him in recounting the discovery.

“I had a joke with Mike [Morwood],” says Saptomo. “I told him if that he left for Jakarta, we would find something big.” And sure enough, on the next-to-last day of the 2003 field season, local digger Benyamin Tarus scraped a trowel through damp clay and hit bone. Benyamin called over Wayhu, who in turn called in the bone expert, Rokhus Awe Due.

Rokhus has worked at Flores digs since 1963 and looks like a living fossil in his own right. But he had no trouble scrambling 5.9 meters down into the shored-up mine shaft that the team had dug over the last two months. There he fixed his eyes on a bulging brow ridge and told Wahyu he was “200% certain” they were looking at an archaic human.

The bone was as soft as the clay it was buried in and Thomas knew drastic measures were needed to secure it for excavation. So he scoured Ruteng to buy UHU glue and nail polish remover—every bottle he could find. Thomas rummages through his tinctures and produces a dainty vial of Tokyo Night. “All the people think we’re crazy,” he laughs. But Thomas’ home-brewed hardening agent allowed the team to recover a nearly complete ancient hominid skeleton—one of just a few throughout the world—and deliver it to their “bone lab” at Hotel Sindha. There he and Rokhus and Wahyu stayed up all night, carving at clay with satay sticks. Their operation revealed a tiny skull, no bigger than a jumbo grapefruit.

Rokhus had first reported to Morwood that they had found a young child. But now he saw worn teeth and fused sutures on the skull. He was forced to conclude that this was a tiny adult—about the height of a five-year-old.

“I was stunned.” Morwood recalls for an Australian film crew. He was familiar with the “island rule”, whereby large animals shrink due to limited resources and an absence of predators. “But the mere thought that you could have a species of human undergoing the same processes of evolutionary downsizing was dumbfounding.”

Morwood next went to Australia and met with paleoanthropologist Peter Brown, armed with a tooth found earlier that season. Brown was excited to hear about the skeleton, says Morwood, “but when I pulled out a copy of the tooth, that’s when he got really excited. That’s when he offered to buy me a cup of coffee and I knew I was onto something.”

Morwood and Brown rushed back to Jakarta to meet the field team arriving at the Center for Archaeology, bearing Thomas’ prized suitcase. When they opened it, “It was like Christmas,” Morwood says. “Nobody spoke. But Peter went white—the blood just drained from his face.”

One look at the lower jaw of LB1 and Brown knew this was not Homo sapiens. It had no chin, peculiar teeth, and primitive bony ridges under the incisors, last seen in hominids almost two million years ago. Later he would reconstruct the height of LB1 at just over a meter and its brain capacity at less than 400cc, about the size of a newborn baby’s.

Brown was stumped. “For me the skeleton was in the wrong place—Flores not Africa, and at the wrong time—it should have been more than a million years old.” At first he had a hard time believing the carbon date for LB1—just 18,000 years old—but further analysis would confirm this. “It is not so easy to think outside the known universe to the extent that was necessary with Liang Bua,” Brown confesses.

It took Brown months to decide if LB1 was human—if it deserved a place in the genus Homo. Its brain was smaller than that of the most primitive member of that clan. But intense discussion with colleagues eventually led Brown to dub the find Homo floresiensis. On 28 October 2004, “flo” made her official worldwide debut in the journal  Nature. A wee 30-year-old lady, wielding stone tools in a cave kitchen full of Stegodons, came to life on the pages of National Geographic, the Nepal Times and more than 100,000 web sites. Journalists jumped on her discoverers’ nickname: “Hobbit”. She even had large feet.

The sensation around hobbits caught Morwood off guard. “Normally the stakes in archaeology are pretty small,” he says. “It’s quite extraordinary to have the stakes get big. Suddenly the whole game changes.”

“I was the first to notice the pathology,” Maciej Henneberg tells me. The University of Adelaide anatomist is boarding a plane chartered for the Liang Bua field trip organized by hobbit skeptic Tueku Jacob. A radio reporter called Henneberg at 7 a.m. on the morning follow the release of the Nature paper, requesting feedback on the discovery in Flores. “I said ‘What discovery?’, then told her to call me back in an hour.” Henneberg read the paper online, and was immediately wary of Homo floresiensis. He diagnosed LB1 as a modern Homo sapiens with microcephaly, a disorder that cripples brain growth. Within hours his reaction hit the air waves.

Today it’s Henneberg who feels Brown came to hasty conclusions. “The whole problem is that people create species first, then compare them.” By now we’re winding through rice paddies in a chartered car, en route to the hobbit cave. I point to a pretty view, but Henneberg has no time for that. “People find a few bones, call it a new species and then it persists.”

“These things are much harder to undo,” adds Alan Thorne, a paleoanthropologist from Australian National University.

“It’s like elves,” nods Henneberg. “If you invent a story about elves, they persist in human memory and you can hear them everywhere in song. It’s nearly impossible to reject a hypothesis that has been built outside of a scientific framework.”

Thorne and Henneberg are co-authors with Jacob on a 2006 paper that says LB1 is a pygmy Homo sapiens of the Austromelanesian race (the group that includes Australian aboriginals). Thorne has compiled some 145 features that define Australian aboriginals and contends that “there isn’t a single feature that would exclude LB1 from that population.”

Later, when I pass along this claim to Peter Brown, his answer is blunt: “Are you familiar with the word ‘crap’?” Brown didn’t attend the symposium—he knew he’d find it infuriating. Over email he insists, “This is a complete fiction, which will become obvious in publications later this year.” Brown is working on a detailed description of the two Liang Bua mandibles recovered to date, and expects to revise classification of the Flores hominid. “I don’t think it’s Homo,” he says. “Certainly not Australopithecus.” Until publication, this is all he will reveal.

The 2006 paper from Jacob et al. also claims pathology. Using photos that mirror-image left and right halves of the skull, the authors say LB1 was deformed. But Dean Falk, a brain specialist at Florida State University, refutes that argument with quantitative analysis of a hobbit skull CT scan. And William Jungers, a lower limb expert from Stonybrook University, can’t help but laugh at the authors’ assessment of the Liang Bua femurs. Jacob’s team questions if LB1 walked with a limp—or walked at all—while Jungers questions if Jacob can properly line up bones. “One femur is missing its head so it rotates a bit more than the other when you lay it flat on the table,” he scoffs. “And they claim LB1 was the microcephalic!”

Microcephaly was a hot topic at Jacob’s symposium. Robert Martin from Chicago’s Field Museum repeated past concerns: “The brain of LB1 is simply too small to be explained by any normal arguments.” A specialist in body proportions, Martin pointed to geometric curves that plot brain size relative to body size for hominin species as well as the upward trend of brain size through time. LB1 sank to the bottom of the deep end on both plots. Chalking this up as an aberrant species, says Martin, calls for special pleading. He still sees LB1 as an aberrant individual.

Henneberg backs up Martin’s claim: “One of the criteria we use for determining paleopathology is falling out of normal distribution by more than three standard deviations.” LB1 falls out by four or five. Henneberg says this is due to stunted brain growth—microcephaly—a symptom of some 400 syndromes that he and his colleagues have tallied up.

Dean Falk says she doesn’t need 400 syndromes—just one in hand and she’d be convinced. “Find us one specimen that shows the same features as LB1 and the story’s over,” she told a symposium panel. “That’s all we ask.”

Falk’s presentation of brain case CT scans for LB1, microcephalics and healthy humans showed that LB1 is similar to a healthy human—its brain lacked distinctive microcephalic features —but also unique. She’s 100% certain it’s a new species. And while hobbit brains were small, her hunch is that they were well-organized. Enlarged temporal and frontal lobes on floresiensis suggest that she was a planner and an abstract thinker and maybe—just maybe—she could speak.

Bouncing to the end of the navigable road en route to the hobbit discovery site, our convoy of experts piled out of 14 cars and gathered on a narrow bridge. Morwood had organized seating arrangements for the journey and, as hoped, bloodshed amongst delegates had so far been averted. But now academic arch-enemies found themselves mulling about in dangerous proximity, unprotected by their PowerPoints. Morwood, himself, was on a collision course with Robert Eckhardt—the guy who’d accused him of “neutron bomb science”—when a band of little people saved the day. Local elders dressed in colorful sarongs and head scarfs burst into song and beckoned researchers to join their procession toward the cave.

Surely every visitor that day had seen pictures of Liang Bua. But no one—not even the most hardened hobbit-basher—could hide their humbled awe when they rounded a bend and first laid eyes on a gaping natural cathedral. The Liang Bua entrance is vast, yet somehow obscured by topography and tropical vegetation. As you penetrate it via a narrow path along a cliff face, the cave reveals itself to be vaster still, draped in stalactites, soft light and crisp, inviting air. There’s no denying that this would make a cozy hole for hobbits as well as hobbitologists. An area half the size of a football pitch allowed plenty of room for delegates to spread out, cluster in cliques and steal furtive glances at enemy camps. It was as awkward as a high school dance until the scene was swarmed by villagers and local officials gawking at the new arrivals.

The crush of people in the cave made it difficult to locate the archaeologists—Thomas Sutikna and crew. Though they had co-authored academic papers with many of that day’s visitors, few people would recognize them. In part, this was because the team had not been invited to Jacob’s symposium. Nor had they been officially informed of this visit. When I later asked Koeshardjono, Jacob’s right hand man who led the field trip, why the Liang Bua archaeologists weren’t included, he explained that they only invited “experts”. And so Sutikna, Wahyu Saptomo, Wasisto, Jatmiko and Rokhus stood over stone tools and Stegodon jaws sharing years of experience by way of ad hoc, one-on-one interpretation.

Most impressive to see were two deep shafts under excavation. Sector XII, at six meters depth, likely spans 100,000 years—the longest recent record anywhere in Southeast Asia. Use of shoring planks, platforms and ladders allows for the deep penetration of time, methods that Malay and Philippine symposium delegates will soon try at home.

The sheer walls of Section XII revealed a layer cake of deposits. The stand-out was an 11,000-year-old band of white ashy silt that the archaeologists claim divides the era of modern humans (above) and hobbits (below). Alas, no hominid bones were found at this hole, now hitting bedrock, but Stegodon bones and hundreds of stone tools were recovered.

As of this writing, the archaeologists place their hope in a second shaft, Section X. Modern human layers offered up a wealth of tools, including a manufacturing site. During the symposium visit, Sutikna and his team were just dipping through Section X’s ashy threshold, penetrating the Age of Hobbits. Working immediately adjacent to Sections VII and XI, where LB1 was recovered, feels auspicious. With luck, Sutikna will soon be re-packing his cherished suitcase.

As the crowds died down, I found the skeptical Alan Thorne in a quiet corner of the cave, enjoying a bit of a revelation. “The most significant thing—when you come to this site and you realize how big it is—it increases the chance that this is where it will be resolved. If they’re right,” he allowed, “the next cranium they find here will have a cranial capacity of 450cc.” Could Thorne be ready to believe in hobbits?

I returned to Liang Bua the next day with Mike Morwood and a film crew from Real Pictures. (Watch their film, Alien from Earth — it’s great!) It was Sunday, the archaeologists’ day of rest, and the cave was transformed—as serene, perhaps, as when hobbits had left it or when Morwood first visited in 1999.

One of Morwood’s first research questions back then was how people reached Australia. “Flores is important because it’s strategically located. It’s almost exactly halfway between the Asian continental area and the Australian continental area… an obvious migration route.” But Liang Bua told a story counter to what anyone might have guessed.

“Flores is an island where relic populations of very old lineages have survived until very recent times,” Morwood explains, citing Komodo dragons and Stegodons, the latter of which survived on Flores longer than anywhere else on Earth. Such relic populations, he contends, are evidence that modern humans were late arrivals here.

“All around the world,” says Morwood, “island faunas have become extinct fairly quickly when modern humans arrived.” Giant tortoises and dodos leap to mind. Further back, throughout the fossil record of Indonesia, Stegodons disappear right when modern humans appear. Liang Bua provides no exception—it marks a sharp Stegodon/modern human transition just 12,000 years ago. Morwood sees this as the most likely arrival date for Homo sapiens on the island. And since modern people reached Australia some 60,000 years ago, the implication is that they came to Flores from Australia, not the other way around. Australian colonization remains a great, unsolved mystery.

Morwood meanwhile points to a second, more dreadful implication of the faunal replacement at Liang Bua. “It looks like Homo floresiensis is also the survival of a very early hominid lineage that somehow hung out on this refuge island—an ‘island ark’—until just 12,000 years ago.” Proximity and time of death, he suggests, make our own species prime suspects for snuffing out the hobbits.

While the jury’s out on hobbits’ demise, Morwood sets his sights further afield. “If you look at the pattern of ocean currents,” he says, “almost certainly the source area for animals and early hominids coming to Flores is Sulawesi.” He waves north, toward a big island renowned for bizarre relic fauna, and his eyes light up. “We’ll probably have an endemic hominid species in Sulawesi,” he says. And that’s only the beginning. “We’re talking about thousands of islands in this area and hominid arrival in this area almost certainly before two million years ago. We may have hominid species appearing on a number of islands in Southeast Asia.”

This may be Morwood’s last field season at Liang Bua. He’s excited to see younger researchers cutting their teeth on a world-class archaeological site and even more excited to set off in search of Sulawesi’s proto-hobbits. But will he ever convince skeptics of Homo floresiensis?

“Frankly I don’t care!” Morwood’s voice booms through the ancient cave. “We’re talking about a small minority of people. There are people still out there that believe in a flat earth and if anybody wants to believe that Homo floresiensis is a pathological modern human, of Austromelanesian type, of dwarf stature related to the small people up the road, I have no problem with that. But the evidence is otherwise.”

Creative Commons License
Bones of Contention, © Djuna Ivereigh, is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported License. Excerpts may be reproduced with a credit to DjunaPix Indonesia Photography, linked to http://blog.djunapix.com/2010/05/wild/bones-of-contention/.