Tiny arm bone unlocks mystery of Indonesia's extinct 'Hobbit' people
By Will Dunham
Aug 6 (Reuters) -When researchers excavated fossilized fragments of a rod-shaped bone 3-1/2 inches (88 mm) long at a site called Mata Menge on Indonesia's Flores island, the pieces initially were bagged and marked "crocodile bone fragment?" It was only later that they realized what they actually were.
These fragments, dating to about 700,000 years ago, of the upper arm bone, called the humerus, comprise the smallest limb bone known for any member of the human evolutionary lineage - an adult individual of the diminutive extinct species Homo floresiensis. And the fossil has unlocked the mystery of the origin of this species, nicknamed "The Hobbit."
Scientists on Tuesday announced the discovery of this incomplete humerus - missing both of its ends - as well as two fossilized teeth from Mata Menge in the So'a Basin of Flores, where the volcano Ebulobo looms over the landscape. While dental and jaw fossils of the same age previously were found at the site, the humerus is the first Hobbit bone beyond the cranium identified at Mata Menge.
Based on the bone's size, the researchers concluded the individual stood about 3 feet 3 inches (one meter) tall - about three inches (6 cm) shorter than the estimated height of the famous 60,000-year-old Homo floresiensis fossil uncovered in 2003 at the Liang Bua cave site roughly 50 miles (75 km) away.
Since the sensational discovery of Homo floresiensis, scientists have debated its origins. The leading hypotheses were that the Hobbit descended either from an archaic human species called Homo erectus, which arose in Africa and spread to other parts of the world, or from even more primitive species such as Homo habilis or Australopithecus afarensis, not known to have left Africa.
The similarities between the Mata Menge fossils and Homo erectus fossils from Indonesia's island of Java provide strong evidence that Homo floresiensis descended from that species, the researchers said.
"This means that Homo floresiensis experienced dramatic body size reduction from large-bodied Homo erectus, whose body size was similar to us modern humans," said University of Tokyo paleoanthropology professor Yousuke Kaifu, lead author of the study published in the journal Nature Communications.
The Flores fossils are most similar to Homo erectus fossils dating from 1.1 million to 800,000 years ago from Sangiran, Java, Kaifu said, and not the more primitive species.
"The discovery offers support to the idea that an evolutionary process known as island dwarfism tinkered with the genetics of a group of large-bodied Homo erectus that somehow made it from the continental landmass of Asia to the isolated island of Flores, perhaps one million years ago or more," said archaeology professor and study co-author Adam Brumm of Griffith University's Australian Research Centre for Human Evolution.
They reduced drastically in body size on Flores between about one million and 700,000 years ago, giving rise to Homo floresiensis, Brumm added.
Under the island effect, larger-bodied mammals such as elephants - which also resided on Flores - diminish in size over time.
"It is thought that the main reason for this size reduction over many generations is that being small has more advantages than being large on an island. Periodic shortages of food are most likely the main selective force toward smaller body size," said University of Wollongong paleontology professor and study co-author Gerrit van den Bergh.
Homo erectus first appeared roughly 1.9 million years ago, possessing body proportions similar to our own, though with a smaller brain.
The original length of the Mata Menge humerus, dug up in 2013 and properly identified in 2015, would have been about 7.9-8.3 inches (200-211 mm). That compares to the 9.6 inches (243 mm) for the later Liang Bua Hobbit and to an average of about 11.8 inches (299 mm) for modern-day people.
"I first thought that the tiny humerus could be a child," Kaifu said.
A microscopic examination of a sample of the Mata Menge humerus revealed evidence of a process called bone remodeling, showing it came from an adult.
Ten Homo floresiensis fossils, including some described in 2016, from at least four individuals - two adults and two children - have been excavated from sandstone at Mata Menge, along with stone tools. The fossils suggest that these Homo floresiensis progenitors were even slighter smaller than the later Hobbits.
Homo floresiensis went extinct not long after our species arrived in the region.
"I think our species very likely was the culprit," Brumm said. "This isolated lineage of archaic hominins seems to have existed on Flores for an extremely long time, and then it disappears not long after Homo sapiens is known to have established a presence in the region. That hardly seems a coincidence."
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Reporting by Will Dunham, Editing by Rosalba O'Brien
تازہ ترين خبريں
دستبرداری: XM Group کے ادارے ہماری آن لائن تجارت کی سہولت تک صرف عملدرآمد کی خدمت اور رسائی مہیا کرتے ہیں، کسی شخص کو ویب سائٹ پر یا اس کے ذریعے دستیاب کانٹینٹ کو دیکھنے اور/یا استعمال کرنے کی اجازت دیتا ہے، اس پر تبدیل یا توسیع کا ارادہ نہیں ہے ، اور نہ ہی یہ تبدیل ہوتا ہے یا اس پر وسعت کریں۔ اس طرح کی رسائی اور استعمال ہمیشہ مشروط ہوتا ہے: (i) شرائط و ضوابط؛ (ii) خطرہ انتباہات؛ اور (iii) مکمل دستبرداری۔ لہذا اس طرح کے مواد کو عام معلومات سے زیادہ کے طور پر فراہم کیا جاتا ہے۔ خاص طور پر، براہ کرم آگاہ رہیں کہ ہماری آن لائن تجارت کی سہولت کے مندرجات نہ تو کوئی درخواست ہے، اور نہ ہی فنانشل مارکیٹ میں کوئی لین دین داخل کرنے کی پیش کش ہے۔ کسی بھی فنانشل مارکیٹ میں تجارت میں آپ کے سرمائے کے لئے ایک خاص سطح کا خطرہ ہوتا ہے۔
ہماری آن لائن تجارتی سہولت پر شائع ہونے والے تمام مٹیریل کا مقصد صرف تعلیمی/معلوماتی مقاصد کے لئے ہے، اور اس میں شامل نہیں ہے — اور نہ ہی اسے فنانشل، سرمایہ کاری ٹیکس یا تجارتی مشورے اور سفارشات؛ یا ہماری تجارتی قیمتوں کا ریکارڈ؛ یا کسی بھی فنانشل انسٹرومنٹ میں لین دین کی پیشکش؛ یا اسکے لئے مانگ؛ یا غیر متنازعہ مالی تشہیرات پر مشتمل سمجھا جانا چاہئے۔
کوئی تھرڈ پارٹی کانٹینٹ، نیز XM کے ذریعہ تیار کردہ کانٹینٹ، جیسے: راۓ، خبریں، تحقیق، تجزیہ، قیمتیں اور دیگر معلومات یا اس ویب سائٹ پر مشتمل تھرڈ پارٹی کے سائٹس کے لنکس کو "جیسے ہے" کی بنیاد پر فراہم کیا جاتا ہے، عام مارکیٹ کی تفسیر کے طور پر، اور سرمایہ کاری کے مشورے کو تشکیل نہ دیں۔ اس حد تک کہ کسی بھی کانٹینٹ کو سرمایہ کاری کی تحقیقات کے طور پر سمجھا جاتا ہے، آپ کو نوٹ کرنا اور قبول کرنا ہوگا کہ یہ کانٹینٹ سرمایہ کاری کی تحقیق کی آزادی کو فروغ دینے کے لئے ڈیزائن کردہ قانونی تقاضوں کے مطابق نہیں ہے اور تیار نہیں کیا گیا ہے، اسی طرح، اس پر غور کیا جائے گا بطور متعلقہ قوانین اور ضوابط کے تحت مارکیٹنگ مواصلات۔ براہ کرم یقینی بنائیں کہ آپ غیر آزاد سرمایہ کاری سے متعلق ہماری اطلاع کو پڑھ اور سمجھ چکے ہیں۔ مذکورہ بالا معلومات کے بارے میں تحقیق اور رسک وارننگ ، جس تک رسائی یہاں حاصل کی جا سکتی ہے۔
