In one of the most spectacular fossil finds in decades, anthropologists announced on Thursday that they have found the bones of a tiny human who is a twig in mankind's family tree.
The height of a chimpanzee and with a skull the size of a grapefruit, the wee hominid lived around 18,000 years ago on the remote eastern Indonesian island of Flores, they say.
He is believed to be an extinct Asian offshoot of Homo erectus, the forerunners of Homo sapiens, as anatomically modern man is called.
But he was so dramatically different from either H. erectus or H. sapiens that he should be classified as a separate species of Homo, said the team report in the British weekly scientific journal Nature.
He measured just a meter or so (3.25 feet) high and had a brain size of 380 cc (13 fluid ounces), just a quarter of modern man's.
They have dubbed the hominid Homo floresiensis, "Man of Flores."
He is the smallest of the 10 known species of the genus Homo, the hominid that arose out of Africa about 2.5 million years ago.
Their theory, based on the previous discovery of stone tools on Flores, is that H. erectus arrived on Flores about 800,000 years ago and became genetically marooned from the rest of mankind.
Over thousands of years, evolutionary pressure caused the colony to shrink in height - paucity of food and over-population favored the survival of smaller individuals, whose genes were then passed on to their infants.
"We interpret H. floresiensis as a relict lineage [of Homo] that reached, and was then preserved on, a Wallacean island refuge," say the authors, led by Peter Brown of University New England in Australia.
"In isolation, these populations underwent protracted, endemic change."
As the millennia passed, H. erectus petered out in the rest of world, to be replaced by taller hominids with bigger brains.
The most successful was H. sapiens, which strode out of Africa about 150,000 years ago and eventually conquered the planet, becoming the only living species of Homo today.
H. sapiens migrated across southern Asia between 100,000 and 50,000 years ago, according to a conventional scenario.
He then forked northeast, crossing over into the Americas via island stepping-stones to Alaska, and also southeast, to colonize the Indonesian archipelago, the South Pacific, Australia, and New Zealand, according to a popular scenario.
So at some point, H. sapiens also showed up on Flores - possibly living there for tens of thousand years alongside H. floresiensis.
It is impossible to know how the two species interacted. Did H. sapiens slaughter its smaller neighbors? Or did H. floresiensis eventually become extinct because it could no longer compete for food against its bigger cousins?
Another question is whether the two species may have interbred, possibly adding to the genetic mix that is H. sapiens today.
That puzzle also applies to the Neanderthals, the hominids who lived in Europe, parts of Central Asia, and the Middle East for some 170,000 years until they inexplicably disappeared around 28,000 to 30,000 years ago.
"The find is startling... among the most outstanding discoveries in paleoanthropology for half a century," University of Cambridge anthropologists Marta Mirazon Lahr and Robert Foley said in a commentary, also carried in Nature.
"It is breathtaking to think that such a different species [of hominid] existed so recently," they said. "Our global dominance may be far more recent than we thought."
The Flores discovery includes the skull, femur, and tibia, hand fragments and bits of vertebrae from one individual, apparently a female, and a premolar from another.
They were unearthed from the floor of a cave at Liang Bua, in the middle of western Flores, where amateur anthropologists first started excavating in 1965.
The authors are certain that the skeleton, called LB1, is that of a full-grown adult human, not a dwarf H. sapiens or an ape.
Islands are famous for Darwinian selection, for shaping the genetic path of species through climate, terrain, and food availability, and lack of breeding with other species.
Flores was once the home of a dwarf elephant called a Stegodon, the remains of which were found alongside the H. floriensis fossils.
AFP
Tiny hominid is big news in evolution tale
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