An Ancient Human Species Is Discovered in a Philippine Cave Could Change Human History
Archaeologists in Luzon Island have turned up the bones of a distantly related species, Homo Luzonensis, further expanding the human family tree.
The fossils belonged to two adults and one child who lived between 50,000 and 67,000 years ago.
 |
The Ancient bone found in Callao Cave.
|
In the early 2000s, Armand Salvador Mijares, a graduate student at the University of the Philippines, was digging at Callao Cave on Luzon, for traces of the farmers on the Philippines. Soon, he decided to dig a little deeper.
In 2010, more human remains were discovered in the cave and were tentatively known by the scientific community as remains of Homo sapiens. More bones discovered in 2015 by Mijares led to scientific investigation on the real genetics of the human remains. On April 10, 2019, the paleoanthropologist Détroit published studies in the scientific journal Nature, naming the newly identified human species, Homo luzonensis, which lived on the island of Luzon at least 50,000 to 67,000 years ago. The remains consist of seven teeth and six small bones and is the third landmark discovery in all of archipelagic Southeast Asia in regard to ancient human discovery in the last 15 years. Ultimately, the previously discovered Callao Man remains have been reclassified as Homo luzonensis.
In 2010, more human remains were discovered in the cave and were tentatively known by the scientific community as remains of Homo sapiens. More bones discovered in 2015 by Mijares led to scientific investigation on the real genetics of the human remains. On April 10, 2019, the paleoanthropologist Détroit published studies in the scientific journal Nature, naming the newly identified human species, Homo luzonensis, which lived on the island of Luzon at least 50,000 to 67,000 years ago. The remains consist of seven teeth and six small bones and is the third landmark discovery in all of archipelagic Southeast Asia in regard to ancient human discovery in the last 15 years. Ultimately, the previously discovered Callao Man remains have been reclassified as Homo luzonensis.
 |
| The pronounced curve of this toe bone - the proximal phalanx - from a specimen of Homo Luzonensis, an early human found in a Philippine cave, looks more like it came from tree-climbing Australopithecus than from a modern human, scientists say. |
This time frame means luzonensis would have lived at the same time as Neanderthals, Denisovans, Homo sapiens and the small-bodied Homo floresiensis. Like other extinct hominins, luzonensis is more of a close relative than a direct ancestor.
 |
| Several teeth and a few bones may be all that remain of a diminutive species of early human who lived on the island of Luzon prior to 50,000 years ago. |
 |
| Callao Cave is one of the limestone caves located in the municipality of Peñablanca, Cagayan province, in the Philippines. |
Callao Man refers to fossilized remains discovered inside Callao Cave in 2007 by Armand Salvador Mijares. Specifically, the find consisted of a single 61 mm (2.4 in) metatarsal which, when dated using uranium series ablation, was found to be at least 67,000 years old. If definitively proven to be remains of Homo sapiens, it would antedate the 47,000-year-old remains of Tabon Man to become the earliest human remains known in the Philippines, and one of the oldest human remains in the Asia Pacific. It has been noted by researchers that Callao Man was probably less than four feet tall. The Aetas, mountain dwellers today on Luzon Island, could be descendants of the Callao Man.
It was the second time in the 21st century that a bygone member of the human family has been found on southeast Asian islands.
 |
| Callao Cave
The seven-chamber show cave is one of 300 caves that dot the area and the best known natural tourist attraction of the province.
|
In 2003, fossils of another species - Homo floresiensis, dubbed the "Hobbit" due to its diminutive size - were unearthed in a cave on the Indonesian island of Flores, some 3,000 km from the Luzon site.
 |
| The Hobbit 3 ft 6 inches tall |
Homo luzonensis was a contemporary not only of the Hobbit but of our own species, Homo sapiens, which emerged in Africa roughly 300,000 years ago.
 |
| Callao Cave |
The scientists said they could not rule out the possibility that the arrival of our species in the region contributed to the demise of Homo luzonensis.
 |
| Callao Cave |
“The more fossils that people pull out of the ground, the more we realize that the variation that was present in the past far exceeds what we see in us today,” said Matthew Tocheri, a paleoanthropologist at Lakehead University in Canada, who was not involved in the new discovery.
 |
The human right third metatarsal recovered from Callao Cave. |
 |
| Callao Cave |
Researchers on the Indonesian island of Flores had discovered the bones of an extraordinary humanlike species about 60,000 years old. The scientists named it Homo floresiensis.
 |
| The Hobbit |
Some features were similar to ours, but in other ways Homo floresiensis more closely resembled other hominins (the term scientists use for modern humans and other species in our lineage).
 |
| Callao Cave |
Homo floresiensis was able to make stone tools, for example. But the adults stood only three feet high and had tiny brains. This strange combination led to debates about who, exactly, were their ancestors.
 |
| Callao Cave |
The oldest fossils of hominins, dating back over six million years, have all been found in Africa. For millions of years, hominins were short, small-brained, bipedal apes.
Starting about 2.5 million years ago, one lineage of African hominins began to evolve new traits — a flatter face, bigger brains and a taller body, among other features. These hominins were the first known members of our own genus, Homo.
 |
A new species of human living between 50,000 to 67,000 years ago, Homo luzonensis, discovered in the cave was confirmed in April 10, 2019.
|
One hypothesis, then, is that Homo floresiensis evolved from Homo erectus. So here was the question for Philippine archaeologists: Could hominins have reached Luzon as well as Flores?
“That inspired me to go back and go deep,” Dr. Mijares, now a professor at the University of the Philippines, said in an interview.
All told, the fossils came from three individuals. And they were remarkable.
The teeth had a peculiar shape. Some of the front teeth had three roots, for example, whereas those of our species usually only have just one. And the teeth were tiny.
“These adult teeth are smaller than any hominin known,” said Deersity who was not involved in the new study.
“Could it be that these teeth belonged to adults that were even smaller than Homo floresiensis?” she wondered.
 |
| The Hobbit |
The researchers didn’t find enough bones to estimate how tall Homo luzonensis stood. But they do display their own strange mix of traits. One toe bone, for example, looks nearly identical to those of early hominins living in Africa more than three million years ago.
 |
| Callao Cave |
 |
| The stairs going up to Callao Cave. |
“The combination of features is like nothing we have seen before,” said María Martinón-Torres, the director of Spain’s National Research Center on Human Evolution, who was not involved in the new study.
 |
| Callao Cave |
Taken together, Dr. Mijares and his colleagues concluded, the evidence pointed to a new species of Homo.
 |
| Callao Cave |
Drawing such a conclusion from a few bones is risky, acknowledged Huw Groucutt, a paleoanthropologist at the Max Planck Institute for Chemical Ecology.
Nevertheless, “I think the argument for a new species does look pretty convincing in this case,” he said.
 |
| Callao Cave |
Homo erectus may have been the ancestor of the tiny hominins on both Flores and Luzon — perhaps swept to the islands by storms, clinging to trees. It may even be possible that Homo luzonensis descended from hominins that came to Luzon hundreds of thousands of years earlier.
 |
| Callao Cave |
Last year, another team of scientists digging in a different cave on Luzon found the bones of a butchered rhinoceros. Near those remains, they also discovered stone tools dating back 700,000 years.
At the very least, the two studies indicate there were hominins on Luzon 700,000 years ago and 50,000 years ago. The question now is whether they belonged to the same population.
 |
The archaeologists uncovered the remains of a rhinoceros that had been butchered with stone tools. At last, they found tools in the same ancient layer as extinct animal bones near Kalinga, Luzon in 2014. Geochronologists on the team focused on the rhinoceros teeth.
|
Dr. Tocheri suggests, the tiny island hominins had tiny ancestors — perhaps small hominins in Africa that expanded to Asia and wound up on Flores and Luzon, taking refuge from bigger hominins.
 |
| Callao Cave |
“But it begs the question,” Dr. Tocheri added. “If we’re finding these things way over there, there’s got to be a record of them all the way across the continent leading back to Africa.”
Luzon was never connected to the Asian mainland, even when sea level was at its lowest during the Ice Ages. To get there, ancient hominins had to float. Who were they, and how did they get there?
 |
| Philippines and neighboring areas. |
The hobbit connection
Luzon isn’t the first deepwater island to produce such ancient evidence. In 2003, Indonesian and Australian archaeologists uncovered skeletal remains and ancient tools Homo floresiensis nicknamed, the “hobbits.”on the island of Flores.
 |
| The Hobbit |
Scientists called her “Flo”, and she was like nothing they had ever seen. The discovery gave rise to debates that are still raging, 15 years later. Who were the ancestors of the hobbits, and how did they reach Flores? We still don’t know for sure, and the mystery has only deepened since 2004.
 |
"The smallest primate" - Tarsier of Bohol, Philippines.
|
The diversity of the Philippines
Like Flores, the Philippine Islands were once home to large mammals that are now extinct, including the elephant-like stegodonts. Other ancient species still inhabit the island. Ancestors of tiny tarsiers crossed to the islands more than 35 million years ago, while others — like macaques — reached the Philippines much more recently. This island history has given the Philippines a unique biological diversity.
 |
| "The Oldest Tribe in the World" - Philippine Negritos. |
 |
| Philippine Negritos |
Living people in the Philippines are also very diverse. Some groups have continued traditional hunting and gathering lifestyles until very recently, like the Aeta and Agta of Luzon and the Mamanwa of Mindanao. These people have very small body size and look rather different from the larger populations of the Philippines, whose ancestors farmed for thousands of years.
The Aetas, mountain dwellers today on Luzon Island, could be descendants of the Callao Man.
The word Negrito is the Spanish diminutive of negro, used to mean "little black person". This usage was coined by 16th-century Spanish missionaries operating in the Philippines, and was borrowed by other European travelers and colonialists.
 |
The Aetas, mountain dwellers today on Luzon Island, could be descendants of the Callao Man.
|
Anthropologists historically considered the small-bodied people as a distinct racial group, called “Negritos”. They thought that these Philippines groups were closely related to other small-bodied hunting and gathering peoples of southeast Asia and the Andaman Islands. The idea was that all Negrito populations today are remnant survivors of an ancient race that inhabited mainland and island southeast Asia before rice agriculturalists dispersed from southern China across the region.
 |
| Aeta of Luzon |
 |
| "The Oldest Tribe in the World" - Philippine Negrito |
 |
| Philippine Negritos |
 |
| Philippine Mamanwa Tribe |
Recent genetics shows that this historical picture is outdated. Last year, Timothy Jinam and coworkers from the National Institute of Genetics in Japan examined the DNA of these small-bodied groups. They found that the Philippines “Negritos” all share more DNA with other larger-bodied groups in the Philippines and mainland agricultural populations, than they share with mainland “Negrito” groups or Andaman Islanders. Meanwhile, Luzon groups like the Aeta and Agta have some notable genetic differences from the Mamanwa of Mindanao.
 |
| Hunter-gatherers Philippine Negritos |
A curious genetic fact about the small-bodied populations of the Philippines is that they are more “Denisovan” than anyone else outside New Guinea or Australia. The Denisovans were a group that emerged in our evolutionary history around the same time as Neanderthals. Their DNA suggests that the Denisovans separated from the African ancestors of modern humans around 700,000 years ago, and shortly afterward from Neanderthals. But scientists know almost nothing about what the Denisovans looked like, or where they lived. So far we only know about them from the DNA of a few fragments from Denisova Cave, in southern Siberia.
Somehow, the early modern humans who eventually settled in New Guinea and Australia met and mixed with the Denisovans. The modern human ancestors of the Aeta, Agta, and Mamanwa people must have mixed with the Denisovans, too.
 |
| Aeta |
The Callao foot bone is very small, even compared to small-bodied peoples like the Agta. Intriguingly, it is a near-match for the size of a floresiensis foot.
Aeta men are of great interest to genetic, anthropological and historical researchers because at least 83% of them belong to Haplogroup K2b (Y-DNA) also known as MPS is a human y-chromosome haplogroup that is thought to be less than 3,000 years younger than K, and less than 10,000 years younger than F, meaning it probably is around 50,000 years old.
Negritos had little interaction with the Spaniards as they remained in the mountains during the Spanish rule. Even the attempts of the Spaniards failed to settle them in reducciones or reservations all throughout Spanish rule.
According to Spanish observers like Miguel López de Legazpi, Negritos possessed iron tools and weapons. Their speed and accuracy with a bow and arrow were proverbial and they were fearsome warriors.
 |
| Aeta Men |
That high level of Denisovan mixture is not shared by other populations that anthropologists have called Negritos on the mainland or the Andaman Islands. It’s a signature unique to deepwater islands and Sahul. The island connection may mean that Denisovans themselves existed in island southeast Asia before modern humans.
 |
| Reconstruction of the Hobbit |
It is possible, in other words, that the hobbits were far from alone.
 |
| Philippine Aeta women |
 |
| Filipino Aeta kids |
 |
| The Agta tribe spearfishing. |
 |
| The elder Agta Tribe |
 |
| The Aeta lives in the mountains in the Philippines. |
 |
| Callao Cave is one of the limestone caves located in the municipality of Peñablanca, Cagayan province, in the Philippines. |
 |
| Callao Cave |
And in 2016, Gerrit van den Bergh and archaeologist coworkers found stone tools at Telepu, Sulawesi, that are older than 118,000 years. That date may not seem as impressive as the much older artifacts on Luzon and Flores, but it’s still far earlier than modern humans are thought to have arrived in this region.
 |
| Pinacanauan River besides Callao Cave in Cagayan. |
Who were these ancient islanders, and how did they manage these deepwater crossings so long ago?
 |
| Palaui Island, Cagayan, Philippines |
During the last few years, the pace of discoveries in island southeast Asia has markedly accelerated, generating more and more surprises. As these discoveries continue, we may be able to answer some of the basic questions, but I expect many new mysteries will emerge.
 |
| Callao Cave |
 |
| Callao Cave in Cagayan Valley, Philippines |
We don’t know yet if the Luzon toolmakers could have been the same population as the Flores hobbits. The tiny foot bone from Callao Cave hints that there might have been a hobbit-like population on Luzon as well.
 |
| Callao Cave |
Already it’s clear that the history of this region was complicated. Homo erectus inhabited Java by 1.4 million years ago, and someone — maybe erectus, or maybe a different population — reached Flores before 1 million years ago. On Luzon, somebody made stone tools and butchered a rhinoceros before 700,000 years ago.
 |
Callao Cave is located in the Barangays of Magdalo and Quibal in Peñablanca about 24 km (15 mi) northeast of Tuguegarao City, the capital of the Province of Cagayan.
|
 |
| Callao Cave |
Sorting through these possibilities will demand more fossils of Homo luzonensis and perhaps fossils from some of the many islands off the coast of Southeast Asia.
 |
| Entrance of Callao Cave |
It as an amazing opportunity to see several parallel experiments in human evolution on the islands of the Philippines.
 |
| Palaui Island, Cagayan, Philippines |
 |
| Santa Ana, Cagayan, Philippines |
 |
| Callao Cave |
 |
| Santa Ana Beach in Cagayan, Philippines |
 |
| Paradise Island of Palaui in Cagayan |
 |
|
Filipino Native spearfishing happy and content in their peaceful and quiet lives in the Province of Cagayan in Luzon, Philippines.
|
 |
| This is one of the 7,641 islands of the Philippines where they found the remains of the early Humans Homo Luzonensis. It is obvious that they preferred a Tropical Climate. |
