(CNN) – A species of ancient, hobbit-sized human that lived on the Indonesian island of Flores until about 50,000 years ago is puzzling scientists for several reasons.
Homo floresiensis, The scientific name of this extinct species, first discovered almost 21 years ago, called into question the idea that human evolution proceeded in an orderly line from the most primitive to the most complex.
Experts do not know why the Homo floresiensis, Nicknamed the “hobbit” in a nod to JRR Tolkien’s fictional characters, he developed such a tiny body and lived relatively recently, how he crossed the depths of the ocean to reach the island of Flores, where exactly does this tiny “oddball” fit into the human family tree, and why he disappeared.
An analysis of the fossils of Homo floresiensis newly described, published Tuesday in the academic journal Nature Communicationsattempts to answer some of these questions about the tiny human. The remains examined in the new study include a humerus fragment, the lower half of an upper arm bone, and two teeth discovered at a site known as Mata Menge, one of only two places on Flores Island where fossils of the species have been found.
The study's authors say their findings support an existing theory that “hobbits” evolved their small size long ago and were most likely a dwarf version of the The man stood upthe first ancient human to leave Africa about 1.9 million years ago, with a body size and upright gait similar to those of modern humans. Remains of The man stood up on the Indonesian island of Java and elsewhere in Asia and Africa.
Researchers believe that the The man stood up It became isolated on the island about a million years ago and suffered a drastic reduction in body size over a period of about 300,000 years. This type of size reduction happens to other animals on remote islands in response to resource scarcity, the study notes.
“Perhaps there was no need to be large-bodied, which requires more food and takes longer to grow and reproduce,” said lead study author Yousuke Kaifu, a professor at the University of Tokyo, via email. “On the isolated island of Flores there were no predatory mammals or other hominin species, so the small body size was fine.”
Based on the estimated length of the bone, the team calculated that its owner was 100 centimeters (about 3.3 feet) tall. The teeth found at the same site, although smaller in size, showed a “high degree of similarity” to the teeth of The man stood up unearthed in Java.
Digital microscopy of the bone structure indicated that it belonged to an adult and not a child. The complete humerus is believed to have been between 21.1 and 22 centimetres long, the smallest fossil of a human limb bone ever found.
The sediment layer containing the fossils was previously dated to around 700,000 years ago.
This early hobbit was 6 centimeters smaller than the original specimen of Homo floresiensisA nearly complete skeleton was found in Liang Bua Cave about 75 kilometres west of Mata Menge in 2003 and dated to about 60,000 years ago. Liang Bua Cave is the only other place where hobbit fossils have been found.
The authors noted that the size disparity between the two could point to natural variation, such as that seen in modern human populations. Overall, the research suggests that the species' small size remained remarkably constant over a long period.
The newly analysed finds, along with other teeth, a jaw and a skull fragment found at the same site and described above, represent four hobbit individuals. Combined with the more recent Liang Bua fossils, they suggest that the tiny humans were able to thrive on the island despite the presence of predators such as 3-metre-long Komodo dragons and crocodiles.
“The early dramatic reduction and subsequent stability in body size indicated that having a smaller body size on this isolated island was beneficial for the survival of these archaic humans,” the study authors said in a statement.
The Hobbit, together with the later discovery of two other hominids with small bodies and brains who lived relatively recently, the homo stars in South Africa and the A man from Luzon in the Philippines, and the much larger Denisovans, has led to a greater acceptance among paleoanthropologists that there have been many diverse species of humans, including several that coexisted with our own species, a wise man.
Before the discovery of the Homo floresiensisMany experts in human evolution thought that only one human species had existed throughout time, with regional variations.
Not all scientists agreed with the study's interpretation that the The man stood up of large size was the ancestor of the Homo floresiensis and that the hobbit represents a dwarf version of the The man stood upsaid co-author Gerrit van den Bergh, a senior lecturer at the Centre for Archaeological Sciences at the University of Wollongong in Australia.
According to other authors, the hobbit, with its small brain and chimpanzee-like wrists, could be more closely related to small-bodied hominids, such as the a handymanwhich is only known in Africa.
Matt Tocheri, a Canadian professor of Human Origins at Lakehead University in Ontario, said he was not convinced the hobbit was a The man stood up the reduced scale.
“I agree that their evidence indicates that small-bodied hominins were present on Flores at least 700,000 years ago. But why does that have to mean that their immediate ancestors who first arrived on the island were larger?” said Tocheri, who is also a research associate in the Smithsonian Institution’s Human Origins Program.
“I think this question remains unanswered and will continue to be the subject of research for some time.”
Van den Bergh said the remains of the so-called Flores man unearthed in Mata Menge were found between 2014 and 2016. However, the humerus was broken into fragments and was not immediately recognized. One of the study's authors painstakingly reassembled it later.
“The fossils are found in hard sandstone,” van den Bergh said by email. “We are forced to use metal chisels and hammers to break up the sediments, so some of the fossils are recovered in many pieces.”
To resolve the debate over hobbit origins, hominid remains on Flores would be needed dating back further, to the time when they arrived on the island, just over a million years ago, both van den Bergh and Tocheri said.
When the hobbit was first discovered, some experts in human evolution claimed that the bones were those of a modern human with a growth disorder such as microcephaly, a condition that causes an abnormally small head, small body and some cognitive impairment. This claim sparked intense debate, but has since been widely rejected.
According to the study, no signs of disease were found in the humerus.
“Every little piece of Homo floresiensis or any other hominin is incredibly important,” Tocheri said. “These fossils are our window into our species’ shared evolutionary past. Without them, we have no idea what was going on in the past.”
