Homo Floresiensis Skeleton

Homo Floresiensis Skeleton

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Ten Years On, the Flores “Hobbit” Remains an Evolutionary Puzzle

The ancient human known as the “Hobbit” has taken evolutionary biologists on a very unexpected journey. Back in 2004, a team led by archaeologists Mike Morwood and Peter Brown announced the discovery of a three-foot-tall hominin skeleton with an exceptionally small stature and skull, found in Liang Bua cave on the island of Flores in Indonesia. A series of papers released in 2009 described even more fossils from the site, including eight more Hobbit individuals.

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Known to scientists as Homo floresiensis, the Hobbit has no ordinary skeleton. Although parts of its anatomy resembled those of very ancient humans, dating analysis puts the skeleton at about 18,000 years old. That means the seemingly primitive species lived at the same time as modern humans (Homo sapiens), which appeared about 200,000 years ago. In other words, the Hobbit appears to be the latest surviving human species, aside from our own.

This week marks the anniversary of the first publications in Nature describing the Hobbit, and even after a decade of debate, the tiny skeleton continues to provoke controversy. Some experts argue that the skeleton does not represent its own species and is simply a diseased modern human. It’s easy to get lost in competing theories of where H. floresiensis came from and how it got to Indonesia, so here’s our guide to what scientists know and don’t know about this unusual discovery:

Why is the Hobbit so weird?

At first, archaeologists suspected they were looking at the bones of a modern human child. But closer analysis changed their tune. Older hominins, such as the 3.2-million-year-old Australopithecus afarensis, known from the famous “Lucy” fossil, have reinforced jaws, flared hipbones and short legs. Those same features show up in H. floresiensis. The Hobbit’s small skull indicates that the species had a brain the size of an orange, resembling another ancient species Homo habilis, which lived 2.4 to 1.4 million years ago. The Hobbit also possesses the furrowed brow ridges, thick skull and brain structure of Homo erectus, which appeared nearly 2 million years ago. As the researchers delved deeper, it became clear that H. floresiensis had a curious mix of modern and primitive traits. “It’s kind of like all of a sudden there was this laboratory of human evolution that had been occurring on planet Earth that we didn’t even know about,” says Rick Potts, a paleoanthropologist who directs the National Museum of Natural History’s Human Origins program.

A forensic reconstruction of what a Flores Hobbit might have looked like, currently on display at the National Museum of Natural History. At this point, researchers know little of what may have distinguished males from females. (Courtesy of Flickr user Karen Neoh)

Are we sure the Hobbit isn’t just a really short modern human?

Given the young age of the skeleton, some experts have suggested that H. floresiensis represents a modern human with dwarfism, Down syndrome or other pathologies that might explain the small stature and brain. But no modern human pathology can explain all of the Hobbit’s features. Notably, the wrist bones of H. floresiensis don’t contain certain hallmark features of the foot, face and wrist bones of modern humans, such as a boot-shaped trapezoid bone in our wrists. That hasn’t stopped scientists from arguing about whether H. floresiensis truly constitutes a unique species.

So where (evolutionarily speaking) did the Hobbit come from?

Not the Shire. Perhaps the most widely accepted scenario is that H. floresiensis evolved from a version of H. erectus. Coincidentally, H. erectus remains have turned up on the Indonesian island of Java. The earliest H. erectus fossils unearthed outside of Africa, at Dmanisi in Georgia, have also shown that these hominins were not always the large strapping specimens we suspected them to be. Dmanisi skeletons are smaller and retain some primitive features. This all hints that a group of early H. erectus could have made its way to mainland Southeast Asia, and a rogue population could have then been stranded on Flores and given rise to the Hobbit.

Could its origins be even older?

That would certainly make things interesting. Given the similarities in anatomy to both Lucy and Homo habilis, it’s possible that the Hobbit had an older ancestor. If that were the case, we’d need to rethink the spread of ancient humans out of Africa. “It would mean that a whole branch of a human evolutionary tree in Asia had been missing until those fateful discoveries in Liang Bua,” writes Chris Stringer, an anthropologist at the Natural History Museum in London, in a comment paper published in Nature today. However, an Australopithecus species like Lucy probably couldn’t have made the trek from Africa across Asia to Indonesia—it isn’t until the rise of Homo erectus that we see legs strong enough for walking long distances.

Excavations at Liang Bua cave are still ongoing and could yield further clues to the Flores Hobbits' origins. (Courtesy of Flickr user Bryn Pinzgauer)

Homo erectus wasn’t exactly petite. How did the Hobbit get so small?

In short, it shrunk. The leading theories suggest that the ancestor of H. floresiensis may have been subject to insular or island dwarfism. Islands come with a unique set of evolutionary pressures, among them limited and sometimes unreliable resources. To compensate, some animals evolve smaller body sizes that require less energy to maintain. “If you want to survive on an island, you have to basically shrink down all of the organs of the body that are expensive,” says Potts. Animal remains unearthed with H. floresiensis at Liang Bua included a dwarf species of primitive elephant called a Stegodon, along with normal-sized Komodo dragons. Morwood and Brown posited that since island dwarfism was at play on Flores, it could have shaped the Hobbit and may explain the re-emergence of primitive skeletal traits.

And why is its brain so small?

Proponents of more modern origins for H. floresiensis have linked the small brain size to developmental disorders like microcephaly, which stunts the brain’s growth. Initially, researchers questioned whether island dwarfism could indeed shrink the brain to the degree seen in H. floresiensis. But a 2009 study published in Nature found that in hippos undergoing island dwarfism on Madagascar, the brain does get disproportionally smaller than the body. A big brain requires a lot of expensive upkeep, so it makes sense that the brain might be subject to stronger evolutionary pressures.

How did the Hobbit get to Flores?

Even during the last glacial maximum, when sea levels dropped drastically, Flores would not have been accessible from other Indonesian islands or mainland Southeast Asia. The ancestors of H. floresiensis would have needed a boat or raft. Though not out of the realm of possibility, there’s no evidence that H. erectus built boats. More likely, a population of early H. erectus got stranded on a piece of vegetation or land, a micro-island of sorts, that broke off from the mainland and bumped into Flores—this is actually not uncommon in coastal areas during a typhoon or tsunami.

Flores lies about 310 miles from Java. (Gunnar Ries/Wikimedia Commons)

When did the Hobbit get to Flores?

The initial dating of volcanic ash in the sediment around the H. floresiensis fossils puts the bones between 38,000 and 18,000 years old. But other archaeological evidence, such as stone tools in Liang Bua cave, spans from 94,000 to 13,000 years ago. Smithsonian researchers are performing dating analyses on the skeletons in hopes of refining the Hobbit’s age. The oldest stone tools found on Flores date to 1.02 million years ago and may have belonged to H. floresiensis, or more likely their ancestors.

What answers will the next ten years bring?

Any future skeletons unearthed at Liang Bua or elsewhere on Flores could fill in some blanks and probably settle the million-dollar question of the Hobbit’s origins. That answer could impact how we imagine human evolution on mainland Asia and even how we think about human migration out of Africa.

This article has been updated to reflect the most recent age estimate for the oldest stone tools on Flores. A previous version stated that they date back 880,000 years.

About Helen Thompson

Helen Thompson writes about science and culture for Smithsonian. She's previously written for NPR, National Geographic News, Nature and others.

"Hobbit" Skeleton Challenges Evolution

Hunched over a picnic table in a limestone cave, the Indonesian researcher gingerly fingers the bones of a giant rat for clues to the origins of a tiny human.

This world turned upside down may once have existed here, on the remote island of Flores, where an international team is trying to shed light on the fossilized 18,000-year-old skeleton of a dwarf cavewoman whose discovery in 2003 was an international sensation.

Her scientific name is Homo floresiensis, her nickname is "the hobbit," and the hunt is on to prove that she and the dozen other hobbits since discovered are not a quirk of nature but members of a distinct hominid species.

"They butchered the animals here," said the researcher, Rokus Due Awe, studying the toothpick-sized rat bones possibly left over from hobbit meals. Behind him, workers carried out buckets of soil from a cathedral-like cave festooned with stalactites, 130-feet underground.

The discovery of Homo floresiensis shocked and divided scientists. Here apparently was a band of distant relatives that exhibited features not seen for millions of years but were living at the same time as much more modern humans.

Almost overnight, the find threatened to change our understanding of human evolution.

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It would mean contemplating the possibility that not all the answers to human evolution lie in Africa, and that our development was more complex than previously thought.

Critics, however, dismissed the hobbit's discovery as nothing extraordinary. They continue to argue that the hobbit, just 3 feet tall with a brain the size of a baby's, was nothing more than a deformed human. Its strange appearance, they say, could be blamed on a range of genetic disorders that cause the body and brain to shrink.

The feud has played out in top scientific journals. But a growing consensus has emerged among experts on human origin that this is indeed a separate and primitive species that lived in relatively modern times - 17,000 to 100,000 years ago. The November issue of the highly respected Journal of Human Evolution was dedicated to the Flores findings and included a dozen studies supporting the hobbit as a new species.

Chris Stringer, research leader in human origins at the Natural History Museum in London, said the critics are "very much in the minority now." He said that he just returned from a meeting in Arizona of more than two dozen experts on human origins and found widespread support there for the new-species theory. No one, he said, "took the view that this was some weird, pathological freak."

William L. Jungers, a paleoanthropologist at Stony Brook University Medical Center who co-edited the Journal of Human Evolution issue, insisted the debate was over. He has published a study of the hobbit's feet which found it had traits associated with both modern humans and apes.

"This is a new species that cannot be explained by any known pathology," Jungers said.

Africa is central to any narrative about human evolution because it is believed that Homo erectus was the first hominid to leave the continent 1.8 million years ago, and most hominid fossils have been found there.

But the discovery of the hobbit, with its primitive traits, suggests that important stages in hominid evolution may have occurred in Asia, said Morwood, the coordinator of the hobbit dig. For example, he said, it may turn out that Homo erectus evolved in Asia.

"For many people, this was totally unexpected and indicates how little we know about hominid evolution, particularly in Asia," which may have "played a prominent role in some major developments in human evolution," he said.

Stringer, for one, believes the hobbit's ancestors could have been a forerunner of Homo erectus. If fossils are found to prove that, he said it would upend the belief that erectus was the first of our ancestors to make it out of Africa and eventually migrate to China and the Indonesian island of Java.

Instead, something more primitive may have left Africa, evolved into erectus and then returned to the continent.

"We'd have to say something got out earlier than that and we don't have any record of its evolution in the whole of Asia," Stringer said. "That means there is a complete missing chapter of the story of human evolution in Asia if that is correct. That would be very interesting and important if true."

Still, no one who supports the new-species theory suggests the hobbit is a direct ancestor of modern humans. Rather, they believe it represents a previously unknown branch of a pre-modern, hominid lineage.

Morwood, 59, a Willie Nelson lookalike with gray hair and grizzled beard, made his name studying Australian aboriginal rock art and originally came to central Flores in search of the Aborigines' ancestors

He first turned to the Soa Basin, a wind-swept savanna ringed by mountains, where Ngadha people still hunt pig and deer on horseback. Sites there produced stone tools dating back almost 1 million years which indicates Homo erectus or an earlier hominid species reached the island.

In 1999, Morwood accompanied his Indonesian colleagues to Liang Bua cave, which is hidden in the mountainside and overlooks rice paddies.

"Stepping into the cave for the first time, I was immediately struck by its size, and particularly impressed by its suitability for human occupation," Morwood wrote in "A New Human," his book about the hobbit discovery.

The team found a hobbit arm bone in 2001. Two years later, a worker hit what turned out to be a skull, and soon an entire female skeleton was unearthed. The researchers at the site that day - Due Awe and fellow Indonesians Thomas Sutikna and Wahyu Saptomo - knew they had found something special.

It appeared to be a child because of its size. But Due Awe determined it was an adult based on its worn molars. Even more perplexing, its brain was about one-third the size of a modern human one. Its short legs and potbelly appearance during its lifetime also closely resembled a famous, 3.2-million-year-old African fossil find nicknamed Lucy.

Yet radiocarbon dating on charcoal found next to the skeleton showed it died in the cave only 18,000 years ago. The other hobbit specimens were found to have lived in the cave until at least 17,000 years ago.

"Homo floresiensis is the only species out of Africa with those primitive body proportions," Morwood said. "You go to Africa and you are talking about hominids which are 2 million to 3 million years old. Here, you have a small-bodied, small-brain hominid that lived to a mere 17,000 years ago."

Recognizing the importance of his find, Morwood called in other experts to examine the remains from teeth to toes and determine whether the hobbit was a new species or a diseased, modern human.

Findings suggested a new species: teeth showed similarities to ancestral species, the brain looked nothing like a diseased modern human's, and a wrist looked like it came from an ape or early hominid - not a modern human.

If it is a new species, then who were the hobbits' relatives?

One theory is that the hobbit actually evolved from the much taller and big-brained Homo erectus.

Once Homo erectus reached Flores, according to this theory, it succumbed to what is called the island rule, where animals bigger than rabbits shrink in size because of limited food, and those smaller grow larger because of the absence of predators.

There are plenty of examples of that on Flores, where elephants shrank to the size of cows, while rats grew as big as dogs.

But Morwood, Jungers and others note that this evolutionary process has never been documented in a human population.

They believe the hobbit is descended from a more primitive relative of Homo erectus such as Homo habilis, which lived as early as 2.3 million years ago - before hominids are believed to have left Africa. They maintain that the ancestor evolved over nearly a million years to become Homo floresiensis.

To settle the debate, Morwood says, they need to find bones of the hobbit's ancestors and see whether they resemble Homo erectus or a more primitive hominid.

Already, the team has identified charred and chipped remains of Komodo dragons and pygmy elephants, proving the hobbits cooked over fires. Stone flakes found in the cave show these tiny people hunted and scavenged much larger animals.

This year, the team plans to excavate a spot around a boulder at Liang Bua that is among the most promising untouched areas of the cave. On their wish list is another hobbit skull, more teeth and wrist bones.

"It would be nice to have a whole complete male," Morwood said.
By AP Environmental Writer Michael Casey

First published on March 6, 2010 / 4:32 PM

© 2010 The Associated Press. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed.

Paige Fossil History

The discovery of hominin fossils fascinates me. The moment a bone is exposed, freed from its sedimentary tomb for the first time in thousands–or even millions of years–is a special moment. In the history of paleoanthropology, these moments–particularly the who, where, what, and why of these moments, vary considerably. Sometimes, a primitive face is exposed after a blasting of limestone rock, other times an organized dig carefully reveals the fossil treasures. No matter how the discovery occurs there are always fascinating moments.

The discovery of Homo floresiensis is no exception. The strangely small, human-looking skeleton of LB1 (for more on LB1 see this post) was unearthed during an archaeological excavation searching for evidence of modern humans’ migration into Australia. Unexpected, remarkable, and thoroughly bizarre, the small skeleton that has come to be known as “the hobbit” has made a big impact on paleoanthropology, and its day of discovery deserves some attention.

Liang Bua (meaning cool cave). Image: Wikipedia

Setting the Scene. September 2, 2003. In a cave called Liang Bua, which rests on a terrace in a valley cut by the river called the Wae Racang on the Indonesian island of Flores. Team leader, Mike Morwood, described the cave as “cathedral-like” because of its high roof and “great chandeliers and cones of stalactites” suspended from the ceiling. The field season was winding down, and Morwood had already left the island. Here are a few interesting aspects about that day:

Sections of the excavation pits were collapsing. In fact, the only reason the team was excavating the pit in which they found LB1 is because a different section had been terminated early–after large cracks had formed in the pit and it collapsed. In early August they had turned to a two-by-two meter section on the east wall of the cave called Sector VII.

The skull was uncovered by a local worker, hired to help with the excavation. Benyamin Tarus had been digging through thick, sticky, brown clay about six meters deep in Sector VII when his towel hit something unusual.

The left eye orbit was swiped off in discovery.With one scrape of his towel, Tarus both uncovered the skull and sliced off the left brow ridge. He then alerted others to his discovery and they carefully proceeded to remove the clay. It ultimately took three days of work to get the chunck of earth containing the hobbit out of the ground and to the local lab space.

The bones were crazy soft. The skull, along with additional parts of the skeleton the team uncovered, had to be left in the pit for a couple of days to dry out. Meanwhile, the team scoured the island for nail polish remover to coat and harden the bones! Paleoanthropologist Peter Brown, who flew in weeks later to examine the bones, described the bones’ condition by saying “if you’d stepped on them you would have ended up with a pile of mashed potato.”

Over the next few months, the bones were cleaned, studied, and published as a new species of Homo. These bones are incredibly interesting and I will surely write more about them as they are a focus of my dissertation. Morwood said it well when he wrote, “Homo floresiensis challenges us because she is so unexpected, because she does not fit with many preconceptions about humans evolved and behaved, and what they should look like.” This, Morwood argued, “has led to a sometimes bizarre series of twists and turns in Hobbit’s post-excavation history, all with astonishingly similar precedents in the history of paleoanthropology.” (Hint, I intend to explore those historical precedents!)

For more on the discovery, check out Mike Morwood’s fun book A New Human: The Startling Discovery and Strange Story of the “Hobbits” of Flores, Indonesia.

The Smithsonian Institution's Human Origins Program

Explore our 3D collection of fossils and artifacts: view, rotate, and explore hundreds of 3D scans!

Homo floresiensis LB1 skeleton

Homo floresiensis, LB-1 Skull, Flores Indonesia

This adult female, who died around the age of 30, was only a little over 1 m (3.5 ft) tall. Her brain, estimated at 400 cubic centimeters, was as small as those of chimpanzees and the smallest australopithecines. She had fairly large brow ridges, and her teeth were large relative to the rest of the skull. Her fossils consist of an almost-complete skull and partial skeleton that include her legs, hands, feet, part of her pelvis, and other fragments. LB-1 is the most complete H. floresiensis fossil found to date.

Descriptions of the lower limb skeleton of Homo floresiensis

Bones of the lower extremity have been recovered for up to nine different individuals of Homo floresiensis - LB1, LB4, LB6, LB8, LB9, LB10, LB11, LB13, and LB14. LB1 is represented by a bony pelvis (damaged but now repaired), femora, tibiae, fibulae, patellae, and numerous foot bones. LB4/2 is an immature right tibia lacking epiphyses. LB6 includes a fragmentary metatarsal and two pedal phalanges. LB8 is a nearly complete right tibia (shorter than that of LB1). LB9 is a fragment of a hominin femoral diaphysis. LB10 is a proximal hallucal phalanx. LB11 includes pelvic fragments and a fragmentary metatarsal. LB13 is a patellar fragment, and LB14 is a fragment of an acetabulum. All skeletal remains recovered from Liang Bua were extremely fragile, and some were badly damaged when they were removed temporarily from Jakarta. At present, virtually all fossil materials have been returned, stabilized, and hardened. These skeletal remains are described and illustrated photographically. The lower limb skeleton exhibits a uniquely mosaic pattern, with many primitive-like morphologies we have been unable to find this combination of ancient and derived (more human-like) features in either healthy or pathological modern humans, regardless of body size. Bilateral asymmetries are slight in the postcranium, and muscle markings are clearly delineated on all bones. The long bones are robust, and the thickness of their cortices is well within the ranges seen in healthy modern humans. LB1 is most probably a female based on the shape of her greater sciatic notch, and the marked degree of lateral iliac flaring recalls that seen in australopithecines such as "Lucy" (AL 288-1). The metatarsus has a human-like robusticity formula, but the proximal pedal phalanges are relatively long and robust (and slightly curved). The hallux is fully adducted, but we suspect that a medial longitudinal arch was absent.


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Descriptions of the lower limb skeleton of Homo floresiensis

Bones of the lower extremity have been recovered for up to nine different individuals of Homo floresiensis – LB1, LB4, LB6, LB8, LB9, LB10, LB11, LB13, and LB14. LB1 is represented by a bony pelvis (damaged but now repaired), femora, tibiae, fibulae, patellae, and numerous foot bones. LB4/2 is an immature right tibia lacking epiphyses. LB6 includes a fragmentary metatarsal and two pedal phalanges. LB8 is a nearly complete right tibia (shorter than that of LB1). LB9 is a fragment of a hominin femoral diaphysis. LB10 is a proximal hallucal phalanx. LB11 includes pelvic fragments and a fragmentary metatarsal. LB13 is a patellar fragment, and LB14 is a fragment of an acetabulum. All skeletal remains recovered from Liang Bua were extremely fragile, and some were badly damaged when they were removed temporarily from Jakarta. At present, virtually all fossil materials have been returned, stabilized, and hardened. These skeletal remains are described and illustrated photographically. The lower limb skeleton exhibits a uniquely mosaic pattern, with many primitive-like morphologies we have been unable to find this combination of ancient and derived (more human-like) features in either healthy or pathological modern humans, regardless of body size. Bilateral asymmetries are slight in the postcranium, and muscle markings are clearly delineated on all bones. The long bones are robust, and the thickness of their cortices is well within the ranges seen in healthy modern humans. LB1 is most probably a female based on the shape of her greater sciatic notch, and the marked degree of lateral iliac flaring recalls that seen in australopithecines such as “Lucy” (AL 288-1). The metatarsus has a human-like robusticity formula, but the proximal pedal phalanges are relatively long and robust (and slightly curved). The hallux is fully adducted, but we suspect that a medial longitudinal arch was absent.

A New Genetic Study Suggests Modern Flores Island Pygmies and Ancient Hobbits Are Unrelated

Geneticist Serena Tucci sat in the small Indonesian village of Rampasasa on Flores Island, the only woman in a room full of male researchers and pygmy villagers. Smoke from clove cigarettes swirled through the air and the villagers, whose average height was about 4.5 feet, offered their guests palm wine made from the sap of nearby trees. Slowly, with the help of translators working through three different languages, Tucci and her colleagues explained why they wanted to sample the villagers’ blood and saliva.

Clear communication was important, Tucci now says of that 2013 research trip. Scientists have made lots of mistakes in the past when working with the DNA of indigenous people. But once the villagers understood, they were excited. They wanted to know what their genetics could reveal about their personal history. They wanted to know if they were the descendants of the ancient hominins who once inhabited their island, Homo floresiensis, sometimes called hobbits for their resemblance to the fictional Tolkien creatures.

“The discovery of Floresiensis was one of the most important discoveries of the century and the fact that [the modern pygmies] live in a village very close to the cave [where Floresiensis remains were found] makes them even more interesting,” Tucci says.

The results of their research are published today in the journal Science: the modern pygmies have no relation to Homo floresiensis—though they do contain genetic material from Neanderthals and Denisovans, two extinct hominin lineages. While many modern humans have traces of extinct hominins in their DNA, the particular admixture seen in the pygmies is unique, and tells a fascinating story of how populations from different regions—the islands of Southeast Asia and the East Asia coast—mingled on this island.

“We have been unable to obtain DNA from Homo floresiensis. At least three ancient DNA labs have tried,” said Debbie Argue, a paleoanthropologist at Australian National University unaffiliated with the research, by email. “This study used a DNA statistical method to see if the Rampasasa individuals’ DNA had any indication of unidentified hominin lineages. It didn’t, so it puts the nail in the coffin for anyone who still thought that the Homo floresiensis remains were somehow related to modern humans.”

For many paleoanthropologists, that final nail has been a long time in coming. The discovery of the diminutive remains in Liang Bua cave, announced in 2004, ignited the world of paleoanthropology. The skeletons were initially dated to 18,000 years ago, meaning the tiny Flores people could’ve conceivably existed on Indonesia at the same time as modern Homo sapiens. The adult remains were tiny, less than four feet tall, and had plenty of other odd features. Their skulls had a brow ridge, like that of other ancient hominins, but instead of being one continuous hump across their forehead it broke into two sections. Their feet were huge, much more like the feet of apes than humans. The mixture of modern and archaic traits was a puzzle, one that scientists struggled to solve.

“It is the most extreme hominin ever discovered,” wrote paleoanthropologists Marta Mirazon Lahr and Robert Foley in 2004. “An archaic hominin at that date changes our understanding of late human evolutionary geography, biology and culture.”

Several factors made the hobbits particularly fascinating. First, their proximity to another ancient hominin species—Homo erectus. The first fossil remains of the “Upright Man” were discovered on the nearby Indonesian island of Java in 1891. Could the tiny Homo floresiensis be some descendant of Homo erectus? Could its environment have been the reason for it growing so small?

Flores, while in the same archipelago as Java, is separated by an important geological boundary known as Wallace’s Line. “To get from Java to Flores requires multiple crossings of deep channels and treacherous currents, including one of at least 25 kilometers,” writes John Langdon in The Science of Human Evolution: Getting It Right. That means Flores was home to a very limited number of mammals—hominins, rats, and relatives of elephants known as Stegodon—so food resources might have been scarce. Maybe the hobbits were small because it was the only way to survive.

But other scientists disagreed vehemently that the hobbits deserved their own taxonomical category. They argued that the remains belonged to Homo sapiens struck by some unknown affliction: maybe microcephaly (having an abnormally small brain) or a hormonal disease that caused stunted growth. The pathological hypothesis, while never earning full scientific consensus, remained a thorn in the side of researchers who wanted to treat Homo floresiensis as a novel species.

All that seemed to change in 2016, when a new round of dating placed the Homo floresiensis remains at 60,000 to 100,000 years old, rather than only 18,000. A separate group of researchers found more remains on a different part of the island, similar to the Homo floresiensis skeleton in the Liang Bua cave, only these remains were dated to 700,000 years ago. Along with thousands of stone tools dated to nearly 1 million years ago, the growing body of evidence seemed to move solidly in favor of an ancient and strange species of hominin making the island of Flores their home for tens of thousands of years.

If those second round of dates are correct, it’s no surprise that the modern pygmies are unrelated to Homo floresiensis, says study author Ed Green, a biomolecular engineer at the University of California, Santa Cruz. What did surprise him was what they found regarding the genetics of the short-statured people: Their genes that code for height (or lack of it) are in all of us.

“There’s a whole bunch of variation in all human populations, so that if you need to be short, there’s the genetic material [available]. You just select on it and you can be small-statured,” Green says. Basically, the pygmy villagers aren’t special in terms of their genetics anyone might be significantly shorter if the right genes were selected.

As for how the pygmy people of Rampasasa themselves feel about the study results, that remains to be seen. In a village with no phones or Internet, sharing the data is a bit of a logistical hurdle. “We’re working now to set up a new expedition to Flores to bring the results back,” Tucci says. She’s been working with an illustrator to visually convey the results of the study, so that the villagers will have a memento of their collaboration with the scientists. They’ll also learn more about their own migratory history, how the genetic data shows their ancestors mixing with populations from East Asia and Melanesia. Even if their story doesn’t include the mysterious hobbits, it’s still part of the amazing journey Homo sapiens made across land and sea to all the corners of the world.

Becoming Human

Homo floresiensis is a small-bodied hominin species that is dated to between 95,000 and 17,000 years ago. Known from a single cave on the island of Flores in eastern Indonesia, H. floresiensis displays a surprising combination of cranial features that resemble those of Homo erectus and Homo sapiens, postcranial features (features of the limb and trunk) that most closely resemble those of species in the genus Australopithecus, and a stone tool technology linked to those often associated with H. sapiens. If the fossils assigned this species do not represent a population of pathological H. sapiens, as some researchers have argued, they represent a new hominin species and suggest H. sapiens shared the planet with another species much more recently than previously believed.

The cranial material of H. floresiensis comprise teeth and mandibles (lower jaws) from multiple individuals and a single, nearly complete skull. The skull and teeth share some derived features (features not found in the common ancestor) shared with H. erectus and H. sapiens. The face is small, specifically in facial height (a measurement between the brow and the upper teeth) and exhibits reduced prognathism (how far the upper and lower jaws project out from the face) compared to australopith species. The H. floresiensis molars (the teeth at the back of the jaw) and canines are also relatively small, similar to the condition found in H. erectus and H. sapiens.. These Indonesian fossils also possesses many primitive features similar to earlier hominins. For example, the brain is very small (380 to 420 cubic centimeters) and is more similar to apes and species in the genus Australopithecus. The mandibles and premolars (bicuspid teeth), which represent at least 8 partial individuals, share distinctive primitive traits with both Australopithecus and Homo habilis. The premolars are asymmetrical and elongated with complex tooth roots. The mandibles are relatively robust and large in size yet lack a chin (central part of the lower jaw that protrudes out from the face, found only in H. sapiens mandibles).

In contrast to the cranium, where only one complete skull was found, postcranial remains from multiple individuals have been recovered. The shoulder joint is cranially oriented (toward the skull) and the clavicle (collar bone) is short and very curved, suggesting the shoulder was high on the torso, as seen in apes and species in the genus Australopithecus. Other aspects of the postcranial skeleton of these Flores finds that are shared with Australopiths include relatively long arms, flared pelves (plural of “pelvis” pelvic blades that extend beyond the hip joint) and relatively short legs. Moreover, the hand and wrist of H. floresiensis seem to be more primitive than even the earliest representatives of the genus Homo (H. habilis) and closely resemble the shape found in Australopiths. The primitive morphology (size and shape) of the H. floresiensis hand and wrist suggests this species lacked the ability to precisely manipulate items with their hands. Interestingly, the foot of this species is similar to H. sapiens in some respects: the big toe is aligned with the other toes and the bones are thick and robust. Nevertheless, the overall foot morphology exhibits a generally primitive pattern. For instance, the foot is approximately 20 centimeters in length, much longer than any H. sapiens foot from an individual of comparable height to the short statured Homo floresiensis individuals, resembling more closely the length of chimpanzee and australopith foot. The toes exhibit primitive features such as long and curved lateral toes (the four toes to the outside of the feet all but the hallux or big toe) and the hallux is quite short in comparison to that possessed by H. sapiens . The H. floresiemsis foot also seems to lack the longitudinal arch that is characteristic of H. erectus and H. sapiens.

Some researchers argue the Flores remains are those of a diseased individual of our own species and have suggested a number of pathologies that could explain the mosaic of features exhibited by these remains. Pathologies that have been suggested include various forms of microcephaly (a class of genetic disorders in which the head and brain are abnormally small) and growth disorders, such as hypothyroidism (a condition in which the thyroid gland does not produce enough hormones that regulate the body’s metabolism) and Laron’s Syndrome (a genetic disorder in which the body does not process growth hormones normally). Detailed comparisons of the H. floresiensis material, however, seem to provide little support for these hypotheses because measurements of the remains fall outside of modern H. sapiens ranges of variation, even when compared to those with the aforementioned pathological conditions. Moreover, no pathological syndrome seems to adequately explain the suite of features exhibited by H. floresiensis. The fact that all of the individuals found at the cave site exhibit similar cranial and postcranial morphology casts further doubt on the hypothesis that the H. floresiensis remains are those of pathological H. sapiens, as it is unlikely multiple individuals would show signs of relatively rare diseases.

Considerable attention has also been paid to the evolutionary history of Homo floresiensis—e.g., how did it get to Indonesia and of which previously known hominin species is it a descendant? Some researchers have suggested H. floresiensis represents a dwarfed descendent of Asian H. erectus populations. However, there is no evidence for larger-bodied (non-dwarfed) ancestors of H. floresiensis on the island, making this hypothesis difficult to test. This fact and H. floresiensis’ primitive anatomy (brain size, limbs, pelvis, hands and wrist) has led some anthropologists to postulate the remains are evidence of a pre-Homo erectus migration of an earlier species in the genus Homo or a species in the genus Australopithecis. Another hypothesis is that H. floresiensis descended from an earlier, more primitive type of H. erectus (such as that represented by H. erectus remains from the site of Dmanisi in the Republic of Georgia see essay on H. erectus). Most researchers agree the current anatomical evidence shows that H. floresiensis is in many ways more similar to early Homo species (e.g., Homo habilis) than to later Homo species. This observation supports the idea that the ancestors of H. floresiensis left the African continent before the evolution of H. erectus, but the precise origins of this species remain unknown.

The stone artifact assemblages found in association with the skeletal remains of H. floresiensis are dense and demonstrate continuity in production method and tool type throughout the cave deposits. There are a large number of bifacial (struck on both sides) and radial (struck from the outer edge towards the center) cores (rocks from which pieces [flakes] are chipped to produce tools), similar to the Oldowan stone artifact assemblages in East Africa. More complex tools—e.g., points (sharpened, pointed tools), perforators (tools designed to make holes or incisions), blades (flake that is at least twice as long as it is wide) and microblades (blades less than 10 mm, often components of composite tool technology)— have also been recovered. The combination of primitive, Oldowan-like core technology with more advanced tool assemblages is quite uncommon in the archaeological record and make interpretations of the stone tool assemblages found in association with H. floresiensis difficult. Some researchers have questioned whether H. floresiensis had the cognitive capacity to make the more complex tools, citing its small brain size. However, no skeletal remains of H. sapiens have been found at sites bearing Homo floresiensis skeletal material and artifacts commonly associated with the symbolic behaviors of Homo sapiens (e.g., personal ornaments, pigments, and formal disposal of the dead) are also absent, suggesting that H. floresiensis was the manufacturer of all of the tools found at this site.

Researchers have recently recovered stone tools from a site close to the cave on Flores Island. This site dates to roughly 1.02 million years ago and therefore provides a new minimum age for hominin inhabitation of the island. The artifacts found at this site are similar to those found at the original site they are small flakes and both bifacially and radially struck cores. However, the absence of skeletal remains at this second site disallows the establishment of a direct link between H. floresiensis (or any other hominin species) and this stone tool assemblage.

The reconstructed paleoenvironment for H. floresiensis spans three cycles of glacial (cold, dry periods) to interglacial (warm episodes between glacial intervals) changeovers. The earlier cave sediments suggest a wet, rich surrounding environment with dense forests. However, a shift is indicated after 39,000 years ago and Flores begins a transition to more arid conditions. There is a reduction in rainfall and forest cover, as well as the development of widespread grasslands. The environment changed yet again 17,000 years ago and became gradually more wet. The appearance of parrots in the assemblage suggests that the local flora was changing into a more closed canopy forest, similar to present day environments.

Watch the video: Homo Floresiensis - Ancient Human (August 2022).