June 12, 2019

A recent reexamination of an important fossil discovery shows that Denisovans, a mysterious group of prehistoric people in Asia, lived in the high-altitude environment of the Tibetan Plateau long before the ancestors of modern Tibetans and Nepalese arrived. The fossil, a Denisovan mandible (lower jawbone) fragment, proves that these ancient humans were the first hominids to settle in that harsh environment where altitude sickness is a constant danger. The scientists studying the fossil also believe that modern people living on the Tibetan Plateau owe their survival to these Denisovan ancestors.

This virtual reconstruction shows details of the Denisovan mandible found on the Tibetan Plateau in 1980. It is some 160,000 years old. Credit: © Jean-Jacques Hublin, MPI-EVA, Leipzig

Chinese scientists recently reexamined the mandible fossil, which was excavated in Tibet in 1980. The jawbone fragment containing a few teeth was unremarkable. However, the scientists were hoping to determine the age of the fossil and extract proteins and genetic material using techniques that were not yet invented in the early 1980′s. The scientists were surprised when dating methods showed the fossil was about 160,000 years old. Scientists had previously believed that the early human populations alive at the time could not survive the harsh environment of the Tibetan Plateau.

The Denisovan mandible was found in this Tibetan Plateau cave, a tourist site and Buddhist refuge, in 1980. Credit: © Dongju Zhang, Lanzhou University

Analysis of proteins extracted from the jawbone fossil showed that it belonged to the mysterious Denisovans, a population previously known only from a few skeletal remains found in the Altai Mountains of southern Siberia. Denisovan DNA has similarities to that of the modern indigenous (native) peoples of Australia, New Guinea, the southern Philippines, and other Pacific Islands. Denisovans contributed up to five percent of the genetic material of some people living in these regions today.

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Analysis of the Tibet jawbone shows that the Denisovans were well-suited to a high-altitude environment. They possessed a genetic adaptation that enabled them to withstand the physical effects of hypoxia (insufficient levels of oxygen in the blood) caused by high altitudes. Today, the indigenous people of Nepal and Tibet also possess this genetic adaptation. Scientists now believe that the modern inhabitants of the Tibetan Plateau inherited this adaptation from Denisovan ancestors of the distant past.

May 15, 2019

Last month, on April 10, scientists announced that fossils discovered in the Philippines were evidence of a new and previously unknown variety of human that inhabited the islands some 67,000 years ago. The fossils were found at Callao Cave in northern Luzon, the main island of the Philippines. The scientists determined that the fossils represent a new species of human beings called Homo luzonensis.

Scientists found the bones of Homo luzonensis at Callao Cave on the Philippine island of Luzon. Credit: Callao Cave Archaeology Project

The fossil remains of Homo luzonensis were discovered during excavations that took place at Callao Cave from 2007 through 2015. The remains of three individuals included isolated teeth, a foot bone, two toe bones, two finger bones, and an incomplete thigh bone. Scientists observed an odd mix of anatomical features in these few remains. Some of the features are seen in modern humans alive today. Other features, such as highly curved toe bones, are seen in primitive human ancestors called Australopithecines.

These teeth of Homo luzonensis were found in Callao Cave. Credit: © Callao Cave Archaeology Project

The fossils from Luzon add to the growing list of physically distinct varieties of prehistoric humans known across the world—a list that has complicated the view of human evolution. Scientists understand from fossil evidence that physically modern human beings, Homo sapiens, first appeared in the fossil record of Africa around 200,000 years ago. Scientists believe those people eventually spread to inhabit nearly every corner of the globe. However, many regions of Africa, Asia, and Europe were already occupied by prehistoric humans when Homo sapiens arrived.

This foot bone of Homo luzonensis shows unusual curvature. Credit: © Callao Cave Archaeology Project

The Neandertals, a well known group of prehistoric humans, inhabited much of Europe and Central Asia at least 250,000 years ago. Another group, known informally as the Denisovans, is identified by genetic material recovered from a few bones discovered in Siberia (and recently, Tibet) that date to more than 50,000 years ago. Scientist do not know what the Denisovans looked like because fossil remains are so scarce, but their DNA shows they were distinct from both Neandertals and modern humans. These early people are also different from Homo naledi, a mysterious early human species first discovered at Rising Star Cave in South Africa in 2015. Even more peculiar is Homo floresiensis, a diminutive (very small) variety of prehistoric humans known from fossils discovered on the Indonesian island of Flores in 2004.

Scientist now understand that early Homo sapiens shared their world with several other physically distinct varieties of human beings. These ancient people were more like cousins than ancestors to modern humans. Today, only physically modern people remain. The discovery of yet another previously unknown human species demonstrates that prehistoric people came in many shapes and sizes.

May 11, 2017

A recent anatomical study of Homo floresiensis, a miniature ancient species of prehistoric people, strongly suggests they are not directly related to modern humans. The study, led by Australian National University school of archaeology and anthropology researcher Debbie Argue, found there was no evidence that the diminutive H. floresiensis descended from the much larger Homo erectus, a regional contemporary human species of H. floresiensis.  Many scientists believe H. erectus was a direct ancestor to later humans, including all living people today. Argue and her research team’s findings were published last month in the Journal of Human Evolution.

The skull of Homo floresiensis, at left, is much smaller than that of a modern human, shown on the right. Recent research suggests H. floresiensis is a unique species unrelated to modern humans. Credit: © AFP/Getty Images

First discovered in 2004, H. floresiensis is a species of prehistoric human that is strikingly small in stature. The species is known only from skeletal remains discovered on Indonesia’s Flores Island in Southeast Asia. The bones show that adults in this population were little more than 3 feet (90 centimeters) tall. Adults also had a brain about one-third the size of a modern human brain. The species was nicknamed “hobbits” after the short people in the fiction of English author J. R. R. Tolkien.

Previous to this most recent study, many researchers suspected that H. floresiensis descended from a group of early human beings, probably H. erectus, that had dispersed from Africa more than 1 million years ago. The scientists theorized that a group of H. erectus became isolated on remote Flores island long ago and gradually evolved (developed over time) a smaller body size. They may have died out when physically modern humans arrived on the island.

However, the new study findings show that H. floresiensis was probably descended from a far more primitive ancestor than H. erectus. The study indicates that another species of early humans, called Homo habilis, is a more likely ancestor to the Flores “hobbits.” H. habilis is the most ancient member of the genus Homo, the scientific name for the group of species that includes modern humans. H. habilis is known from fossils in Africa that date from about 2.4 million years ago to about 1.7 million years ago. Yet, to date, no fossils of H. habilis have been discovered beyond the African continent. Many scientists believe that H. habilis did not possess the intelligence or technology necessary to migrate into new environments outside of their homeland. If the hobbits of Flores Island—some 5,600 miles (9,000 kilometers) from Africa’s east coast—are indeed descendants of H. habilis, then scientists will have to reevaluate their ideas about H. habilis as they continue to study and learn about prehistoric peoples.

September 12, 2016

Bigfoot and Yowie (a large, hairy ape said to live in the wild regions of Australia) might be mere legends, but one giant ape was certainly more than myth. Standing at a whopping 10 feet (3 meters) tall and weighing more than 900 pounds (400 kilograms), Gigantopithecus was about twice the size of a large male gorilla, making it the largest ape that ever lived. Gigantopithecus walked on its hands and fists, like today’s great apes, and roamed the tropical forests of what are now southern China, northern Vietnam, and northern India. Scientists believe that Gigantopithecus was related to ancestors of the modern orangutan.

A Gigantopithecus replica (known as “Mr. G”) was installed at the Museum of Man in San Diego, California, in 2003. Credit: © ZUMA Press/Alamy Images

Gigantopithecus’s fellow jungle creatures had only to worry about being squashed, because the colossal ape was not a meat-eater. Instead, it ate such hardy foods as bamboo and durian (a tropical fruit with a hard, prickly outer skin), using its large jaws and teeth to chew the tough plant matter. It is quite possible that crocodiles and ancient relatives of tigers and hyenas fed on Gigantopithecus young, but adults were so enormous that predators probably left them alone.

Gigantopithecus lived from more than 8 million years ago to about 200,000 years ago. It may have disappeared as the result of a shift in southern Asia’s climate about 1 million years ago, when conditions became colder and drier and the giant ape’s forest home began to shrink. Scientists believe that Homo erectus, an ancient relative of humans, crossed paths with Gigantopithecus and may have hunted it, playing a role in the monstrous beast’s extinction.

May 21, 2014

The discovery of a nearly complete skeleton of a young girl who died nearly 13,000 years ago in what is now Mexico is providing evidence that anthropologists claim will end a decades-old debate over the origins of Native Americans. A diverse team of scientists led by anthropologist James Chatters published a description of the skeleton, which included preserved DNA, in the May 16 issue of Science. The discovery may finally end an often heated, decades-long debate among anthropologists over why Native Americans do not resemble Paleo-Indians, the first people to migrate to the Americas.

Underwater archaeologists discovered the skeleton of the young girl, perhaps only 13 years old when she died, with bones of extinct Ice Age animals. The skeleton was found while the scientists were exploring a submerged cave, called Hoyo Negro (black hole), in the Caribbean Sea, off the Yucatan Peninsula of Mexico. Scientists named her Naia, after a water nymph (maiden) in Greek mythology. The scientists speculate that Naia may have fallen into an underground cave while searching for water and died. As sea levels rose by the end of the Ice Age, the cave was submerged, creating ideal conditions to preserve Naia’s bones along with the bones of other animals that shared her fate.

Genetic studies of Native Americans indicate that their ancestors migrated into the Americas from Asia more than 12,000 years ago. The oldest known Paleo-Indian culture is the Clovis culture, identified by distinctive stone spearheads, called Clovis points. Archaeologists have discovered a only handful of Paleo-Indian skeletons, including Kennewick Man, found in Washington in 1996. However, these ancient skeletons do not physically resemble today’s Native Americans. Paleo-Indian skulls are longer and narrower, with forward projecting faces. These features are most similar to those of native people of Australia and the Ainu, an isolated native population of Japan.

The prehistoric Clovis people made distinctive stone spearheads, called Clovis points. The Clovis are the earliest known Paleo-Indian culture of the Americas (AP Photo).

Some scientists theorize that the Paleo-Indians are not the ancestors of modern Native Americans. They suggest that Native American ancestors arrived from Asia in a later migration and, over time, replaced the Paleo-Indians. Other scientists disagree. They argue that the physical features of Paleo-Indians evolved over thousands of years, giving rise to modern Native Americans.

Now, Naia may end the debate. Naia’s skull has all of the physical characteristics that confirm her identity as Paleo-Indian. However, DNA isolated from her skeleton allowed the scientists to directly link her with living Native Americans. Naia’s mitochondrial DNA—genetic material passed down from mother to child through the egg—included specific sequences of DNA that linked her with ancient populations of northeastern Asia as well as Native American peoples alive today. Similar DNA sequences were recently reported from the only known skeleton of a Paleo-Indian infant, discovered in 2001 at Anzick, a site in Montana. The DNA evidence points to Paleo-Indians as the direct ancestors of modern Native Americans. Naia indicates that the physical difference between her people and modern Native Americans results from evolutionary changes occurring over time rather than separate ancestry.

Additional World Book articles:

• Prehistoric people
• Fascinating Facts About Fossil Feces (a Special Report)
• The First Americans (a Special Report)

October 21, 2013

A 1.8-million-year-old fossil skull will almost certainly force scientists to trim some branches from the evolutionary “family tree” that eventually led to modern humans, paleoanthropologist David Lordkipanidze of the Georgian National Museum in Tbilisi suggested last week. The fossil, known simply as Skull 5, is one of several nearly complete fossil skulls discovered by Lordkipanidze and his team since 1991 at Dmanisi, a fossil site at the eastern end of the Black Sea in the Caucasus Mountains, about 50 miles (85 kilometers) southwest of Tbilisi. The skulls are among the most ancient fossils of human beings found outside of Africa, the cradle of humanity.

The Dmanisi fossil skulls have large browridges and projecting faces that lack chins. Scientists calculate that the skulls held brains that were about half the size of modern human brains. The skulls resemble those of early human ancestors found at fossil sites of about the same age in East Africa. Many scientists divide these ancestors into three species–Homo habilis, Homo rudolfensis, and Homo erectus. Some scientists argue that even more species of early humans existed nearly 2 million years ago, suggesting the human fossil “family tree” was more like a bush with many side branches.

A 1.8-million-year-old human fossil skull from Dmanisi, Republic of Georgia, displays thick skull bones; a low, sloping forehead; and a flat face. The species also had a thick ridge of bone above the eyes, called a browridge. (Mauricio Anton © 2002 National Geographic Society)

Lordkipanidze noted that Skull 5 and four others excavated at Dmanisi almost certainly represent a single population that lived in the same location at the same time. The skulls thus provide an unprecedented opportunity to measure the differences within a group of ancient humans. He found that the skulls showed remarkable differences in such features as the length of the jaw or thickness of the browridges. But, he said, the differences were no greater than those between any five modern people. All people alive today are members of single species, Homo sapiens.

Other anthropologists pointed out that if the five skulls from Dmanisi had been discovered at different sites in Africa, their physical differences could have led scientists to assign the skulls to different human species. The long-established habit of defining new species based on physical variation means that Skull 5 may have been classified as an entirely new human species.

Lordkipanidze and his colleague now theorize that there was only a single human species in Africa 1.8 million years ago and that same species is also represented at Dmanisi. They do not suggest what species that may be, but they recognize it as a member of our own genus, Homo. They argue that one or more of the early Homo species from Africa may need to be pruned from the human family tree.

Additional World Book articles:

• Archaeology
• Prehistoric people
• Stone Age
• Anthropology (2002) (a Back in Time article)
• Anthropology (2007) (a Back in Time article)

May 7, 2013

Grisly proof that the colonists of Jamestown (in what is now Virginia) resorted to cannibalism to survive the terrible winter of 1609-1610 has been unveiled by forensic anthropologists at the Smithsonian Institution’s National Museum of Natural History in Washington, D.C.  Smithsonian scientists displayed the skull and tibia (lower leg bone) of a young girl, nicknamed Jane, that were excavated from a trash-filled corner of historic Jamestown in 2012 by archaeologists with the Jamestown Rediscovery Project. On the skull, they saw telltale cuts and other damage indicating that the girl’s body was crudely butchered to be eaten.

Jamestown as it may have appeared in 1608. The English settlers built a triangular fort to protect themselves from Indians. (© Hulton Archive/Getty Images)

Jamestown, the first permanent English settlement in North America, was founded in 1607 when colonists from England established themselves on an uninhabited peninsula about 60 miles (97 kilometers) from the entrance of the Chesapeake Bay. The settlers made themselves secure by building a triangular fort at the site. However, the Jamestown site was swampy and unsuitable for raising crops. The arrival of more colonists during 1608 and 1609 led to steadily worsening relations with the nearby Powhatan Indians. By winter, war had begun and the Powhatan surrounded Jamestown in an effort to starve the colony into submission.

Jamestown’s population dropped from about 250 to 60 during this so-called Starving Time of 1609-1610, as settlers struggled to survive the seige despite insufficient food. Written records describe how the desperate colonists ate horses, cats, dogs, rats, and even shoe leather. Historians have long known of some accounts that hinted at cannibalism by the colonists. But without physical proof, many scholars dismissed the accounts.

Smithsonian forensic anthropologists pointed out that Jane’s skull shows several parallel cuts made by a sharp metal knife on the forehead, cheek and jaw. Archaeologists are familiar with such defleshing marks, as they are typically found on animals that were butchered for meat. The back of Jane’s skull was split open with an ax or cleaver, and a puncture mark indicates a knife blade was used to pry apart the bones of her skull.

The skull damage and depth of the cuts suggest the work of a hesitant and inexperienced butcher, so Smithsonian scientists do not believe Jane was intentionally killed to be eaten. They speculate that she may have been one of many colonists who arrived in 1609 and later died of starvation or disease during the harsh winter siege.

Forensic anthropologists were able to create a reconstruction of what Jane may have looked like. They determined Jane’s age, sex, and ancestry by examining the skeletal remains. Computed tomography (CT) scans of the skull enabled scientists to fill in missing pieces and create a virtual 3-dimensional model. Demographic analysis showed that her teeth and the shape of her skull are characteristic of an English female about 14 years old. The scientists guessed that she may have had fair skin and light eyes based on English portraits from the 1600′s. A sculptor used this information combined with a detailed knowledge of facial anatomy to create a bust of Jane as she likely appeared shortly before her death.

Additional World Book articles:

• Archaeology
• Anthropology
• Colonial life in America
• Rediscovering Jamestown on its 400th anniversary (Special report)

March 30, 2012

Fossilized foot bones discovered in Ethiopia show that an unknown early human relative from East Africa had apelike feet more suited for life in the trees than for walking. Anthropologist Yohannes Haile-Selassie of the Cleveland Museum of Natural History in Ohio described 3.4 million-year-old fossils in the March 28, 2012, issue of the journal Nature. The scientists concluded that the fossils are from an early hominid. (Also called hominins, hominids are the scientific family that includes human beings and early humanlike ancestors.) However, the fossils are from a foot with long digits and an opposable big toe much like those in modern apes. (An opposable digit can be placed opposite another digit, such as the human thumb to the fingers.) These feature are useful for grasping tree limbs, but they make walking upright on the ground difficult. The fossils also indicate the creature’s foot lacked a distinctive arch, a necessary feature for efficient upright walking.

These new fossils were discovered at a site called Burtele in the Afar region of northeastern Ethiopia. The site is about the same age and only a few miles from Hadar, where fossils of Australopithecus afarensis were first discovered by anthropologist Donald C. Johanson in 1974.  A. afarensis was an early humanlike creature known in part from a fossil skeleton nicknamed “Lucy.” The anatomy of Lucy and other A. afarensis fossils reveals that the creatures were small but walked upright on the ground like modern humans. Lucy’s foot anatomy shows a distinct arch and her big toe was aligned with the other four digits of the foot, the way it is in modern humans. These anatomical features allow for efficient walking on two legs on the ground. Preserved footprints at Laetoli, a site in northern Tanzania that also preserves fossil remains of A. afarensis prove that these creatures walked much the same way as modern humans do as long as 3.7 million years ago.

The skeleton of "Lucy," a prehuman ancestor that lived about 3.2 million years ago, has revealed that this australopithecine walked in much the same way as modern humans do. Lucy lived at about the same time as a newly discovered prehuman species that lived mostly in the trees. (Institute of Human Origins)

Scientists cannot assign a species name to the Burtele fossil without finding additional parts of the skeleton, such as the skull or teeth. But the fossils demonstrate that Lucy and her kind were only one of perhaps several hominid species that inhabited the forests and grasslands of East Africa more than 3 million years ago. Each species was adapted to a different habitat and likely had different anatomy and behavior, including how they moved around. As Lucy and her kind strolled along the plains, their distant cousins may have watched them pass from a perch in the trees.

Additional World Book articles:

• Evolution
• Prehistoric people
• Rethinking the Human Family Tree (a special report of historic interest)
• Anthropology 1974 (Back in Time article)
• Anthropology 1983 (Back in Time article)