Bones and fossil teeth found in Callao Cave in the Philippines are believed to be from a previously unidentified species related to modern humans.

The new species is named Homo luzonensis after the island of Luzon where it was discovered and lived over 50,000 years ago, according to the new study published in Nature.

Co-author and lead member of the team, Professor Philip Piper from The Australian National University (ANU) said the findings represent a major breakthrough in our understanding of human evolution across southeast Asia.

Discovering A New Species

In 2007, the discovery of a single foot bone dating to 67,000 years ago was the earliest evidence of human occupation in the Philippines. Originally believed to have come from a small-bodied member of Homo Sapiens, analysis of an additional 12 fossils unearthed during further excavations in 2011 and 2015 suggested otherwise.

The 13 fossils, consisting of two hand bones, three foot bones, a thigh bone and seven teeth, are believed to be from at least three different individuals – two adults and one juvenile. The remains are dated between 50,000-67,000 years ago, which means that Homo luzonensis would have been alive at the same time as other hominins including Homo sapiens, Neanderthals, Denisovans and Homo floresiensis.

Analysis of the remains have revealed that the new species may have moved around by climbing trees, due to the curved finger and toe bones that are almost indistinguishable from fossils of Australopithecines – a tree climbing ancestor of hominins that walked the earth 2 million years ago.

The small size of the teeth also hint that this new species stood under 4-foot-tall, making it the second species of dwarf human ever discovered. The first being the famous Homo floresiensis, commonly known as ‘the hobbit’, that was discovered 15 years ago on the island of Flores in Indonesia.

Professor Piper said, “The size of the teeth generally, though not always, reflect the overall body-size of a mammal, so we think Homo luzonensis was probably relatively small. Exactly how small we don’t know yet. We would need to find some skeletal elements from which we could measure body-size more precisely.”

Human evolution in Southeast Asia

Some scientists are sceptical over whether there is enough evidence to say for certain that the remains are from an entirely new species. But many agree that it does pose interesting questions about hominin evolution in southeast Asia.

Similarities between the physiology and location of Homo floresiensis and Homo luzonensis fossils suggest they may have descended from another hominin species which evolved in isolation on their respective islands, shrinking in size as resources were much more limited.

Furthermore, remains of a butchered rhinoceros and stone tools near Callao Cave dating to 700,000 years ago points to an ancient human presence being on the island hundreds of thousands of years before the owners of the Homo luzonensis fossils walked the earth.

Professor Piper said, “No hominin fossils were recovered, but this does provide a timeframe for a hominin presence on Luzon. Whether it was Homo luzonensis butchering and eating the rhinoceros remains to be seen.

It makes the whole region really significant. The Philippines is made up of a group of large islands that have been separated long enough to have potentially facilitated archipelago speciation. There is no reason why archaeological research in the Philippines couldn’t discover several species of hominin. It’s probably just a matter of time.”


References

Australian National University – New species of early human

Détroit, F. 2019. A new species of Homo from the Late Pleistocene of the Philippines. Nature, 568, pp. 181-186. Available online.

Tocheri, M. W. 2019. Previously unknown human species found in Asia raises questions about early hominin dispersals from Africa. Nature News and Views. Available online.

Header Image: Rays of second skylight by Rawen Balmaña on Flickr


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