In 1937, Oxford professor J.R.R. Tolkien published The Hobbit, and he followed that up in 1954 with the publication of The Lord of the Rings trilogy, which includes "The Fellowship of the Ring," "The Two Towers," and "The Return of the King."
These works take place in "Middle Earth", which is the main continent of what Tolkien imagined as a mythological past on Earth, set around 6,000 years ago. "Middle Earth" is populated not only by humans, but by Elves, Dwarves, Ents, and Hobbits, all of whom are menaced at one time or another by fellow Middle Earth inhabitants and monsters Dragons, Trolls, and Orcs. Eventually, in Tolkien's imagining, the Elves, Dwarves, Ents, and Hobbits dwindle, leaving only humans.
Now, it's looking more and more like Tolkien may be been somewhat prescient. This year alone, three new species of ancient hominids have been discovered, with the latest one coming just this week.
Scientists at Germany's Max Planck Institutes for Evolutionary Anthropology, the University of Tübingen, and Griffith University in Australia just announced that they have found evidence of a new, distinct group of ancient humans who lived over 7,200 years ago on the Indonesian island of Sulawesi. Sulawesi is part of a group of islands known as Wallacea, which are located between western Indonesia and Papua New Guinea.
In the Leang Panninge cave located on the island’s southern coast, the skeleton of a girl who was 17 to 18 years old was buried at a depth of 75 inches (190 cm). The date of her burial was determined through Carbon-14 dating of a burnt Canarium sp. seed, which was buried alongside her.
Scientists were able to extract the girl's DNA from a skull bone, and they then mapped her entire genome. It showed that the girl belonged to a previously unknown human lineage that appears nowhere else in the world and that the girl's lineage has disappeared. There are no living descendants of this lineage in Indonesia today.
The study's authors concluded that the girl was part of the Toalean people, a group of hunter-gatherers who lived within a 6,000 square mile (10,000 sq k) area, south of Sulawesi Island. The Toaleans brought down prey with stone-tipped arrowheads known as Maros points, and they may be responsible for ancient cave art found on the island.
Surprisingly, the girl's genome also contained bits of DNA in common with the mysterious Denisovans, which are an extinct species or subspecies of archaic humans that lived during the Lower and Middle Paleolithic, which means that the Denisovans were likely more widely dispersed than had been previously thought. The girl's genome also indicted that she descended from the first wave of modern humans to enter the area around 50,000 years, making Wallacea a likely crucial meeting point between archaic and modern humans.
A co-author of the study, Professor Cosimo Posth of the University of Tubingen in Germany, told studyfinds.org, "The geographic distribution of Denisovans and modern humans may have overlapped in the Wallacea region. It may well be the key place where Denisova people and the ancestors of indigenous Australians and Papuans interbred."
Who were the Denisovans?
In 2010, scientists from Russia's Institute of Archaeology and Ethnology of Novosibirsk were excavating at the Denisova Cave in the Altai Mountains of south-central Siberia when they found the tiny finger bone of a child. When scientists from the Max Planck Institute for Evolutionary Anthropology analyzed the bone's DNA, they discovered that it belonged to an entirely new type of hominin (the group consisting of modern humans, extinct human species and all our immediate ancestors), which they named after the cave in which the bone was found.
The Denisovans and the Neanderthals split from the line that led to modern humans about 804,000 years ago, then from each other about 640,000 years ago. This means that the Denisovans must be the descendants of an earlier migration of Homo erectus out of Africa and that they are completely distinct from both modern humans and Neanderthals. Indeed, some features of Denisovans, such as their exceedingly large molars, are more similar to those of Australopithecines than they are to modern humans.
Other ancient humans
In 2003 scientists excavating the Liang Bua cave on the Indonesian island of Flores found the remains of a tiny hominin who would have stood around 3 feet 7 inches (1.1 m) tall. Further digging revealed 15 additional partial skeletons.
It took scientists years to determine that the skeletons weren't diseased modern humans, but were their own separate species, Homo floresiensis, nicknamed "The Hobbit". Incredibly, "The Hobbit" lived on Flores between 190,000 and 60,000 years ago.
Today, it is thought that Homo floresiensis arrived on Flores up to one million years ago, and most likely descended from a population of Homo erectus, before they shrank in physical size. That makes Homo floresiensis a sister species to Homo habilis, and it implies a previously unknown early migration out of Africa.
In June 2021, two new hominins were discovered. As we reported, in 1933 in Harbin City located in China's far north, a Chinese man spotted an unusual skull. At that time, China was overrun by Japanese invaders, and the man didn't want the skull to fall into their hands. Instead, he hid it in an abandoned well where it sat for the next 85 years before the man revealed its location to his relatives prior to his death.
The man's relatives donated the skull to the Geoscience Museum of Hebei GEO University, where scientists immediately recognized that the skull showed a combination of both archaic and modern traits and that it had a brain case large enough to hold a modern human brain.
Researchers dated the fossil to 146,000 years ago and named it Homo longi. They also suggested that the new species, rather than the Neanderthals, are the closest relative to us, Homo sapiens.
Also in June 2021, we reported on an announcement made by scientists at Israel's Tel Aviv University of a discovery at the Nesher Ramla site near the city of Ramla, Israel of a partial skull and jawbone from an entirely new form of human. Named the "Nesher Ramla Hominin," this discovery has upended our understanding of the Neanderthals, who were thought to have originated in Europe before making their way to what is now Israel around 70,000 years ago.
Instead, the Nesher Ramla Homo find implies that Neanderthals lived in the region of modern Israel up to 400,000 years ago, and only later migrated westward toward Europe and eastward toward Asia. It is this Neanderthal population that mated with Homo sapiens when they arrived in Israel around 200,000 years ago.
Two Neanderthals, a Denisovan, and two African humans walk into a bar
In August 2021, we reported on a new analysis made by scientists at Cornell University and the Cold Spring Harbor Laboratory of the genomes of two Neanderthals, a Denisovan, and two African humans. The results showed that 3 percent of the Neanderthal genome came from ancient humans and that the two species must have interbred between 200,000 and 300,000 years ago.
Additionally, the study found that 1 percent of the Denisovan genome also came from an "archaic human ancestor" who was not human, Neanderthal, or Denisovan. The scientists also estimated that we modern humans carry around 15 percent of these "super-archaic" regions in our genomes. But if the DNA didn't come from Homo sapiens, Neanderthals or Denisovans, then who did it come from?
These new discoveries of ancient humans lead to the inescapable conclusion that tens of thousands of years ago, multiple types of hominins roamed the Earth and interbred with one another. Of the five Denisovan specimens that were found in Denisova Cave, one was a young woman who was a Denisovan/Neanderthal hybrid, having a Denisovan father and a Neanderthal mother.
Scientists now believe there may be many more hominin lineages yet to be discovered, and this makes J.R.R. Tolkien far more prescient than we ever knew.