Tuesday 23 April 2019

'New species of human' found in cave throws doubt over evolution theories

Key site: Callao Cave on Luzon island in the Philippines, where fossils of Homo luzonensis were found. Photo: AFP/Getty Images
Key site: Callao Cave on Luzon island in the Philippines, where fossils of Homo luzonensis were found. Photo: AFP/Getty Images

John von Radowitz

A previously unknown species of human that lived at the same time our ancient ancestors were colonising Europe has been discovered in the Philippines.

Bones and teeth of the "hominin" were found in Callao Cave on Luzon, the largest island in the Asian archipelago. They contain a mixture of old and new features that have excited scientists and threaten to overturn accepted theories of human evolution.

Hominins are members of the human family tree more closely related to one another than to apes.

Today, only one species of this group remains, Homo sapiens, to which everyone on Earth belongs.

It was a different story 50,000 years ago, when several varieties of hominin co-existed.

They included our own species, H sapiens, and Neanderthals, both living in Europe and western Asia, the Denisovans in Siberia, and the diminutive H floresiensis -nicknamed "hobbits" - from Indonesia.

Now another name has been added to the list, Homo luzonensis, after scientists analysed an unusual set of fossil remains from Callao Cave.

Several feet and hand bones, a partial thigh bone, and teeth from at least three individuals were unearthed and dated to the late Pleistocene era, as recent as 50,000 years ago.

The teeth are unusual. While the molars of H luzonensis were strikingly small - similar in size to those of modern humans - they shared other characteristics with those of far more primitive hominins, including one known for its massive jaws and teeth.

One of the foot bones had an anatomy distinct from all other known hominins, including modern humans.

In addition, H luzonensis had toes identical to those of Australopiethecus, a primitive species that lived in Africa at least two million years earlier.

It also had primitive-looking fingers, and the fingers and toes were curved - suggesting the creature liked to climb.

Writing in the journal Nature, Dr Florent Detroit, from the Museum of Natural History in Paris, France, and colleagues conclude: "The discovery of H luzonensis underscores the complexity of the evolution, dispersal and diversity of the genus Homo outside of Africa, and particularly in the islands of south-east Asia, during the Pleistocene."

All species of human, both living and extinct, are believed to have originated in Africa. They moved out in two major waves of migration hundreds of thousands of years apart.

The sole representative of the first wave was thought to have been Homo erectus, which spread across the globe more than 1.5 million years ago. However, this theory has looked shaky in recent years, especially with the discovery in 2004 of H floresiensis, and the latest find throws up even more doubts.

Irish Independent

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