Tiny arm bone unlocks mystery of Indonesia's extinct 'Hobbit' people

When researchers excavated fossilised 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 realised 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 fossilised 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 metre) 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