Palaeontologists have unearthed the skeletal remains of what is believed to be a member of the tiniest ancient human species, with an estimated height of just 1 metre. The fossilised arm bone was found on Flores, an Indonesian island, and is speculated to belong to a petite, adult human who lived 700,000 years ago. During this period, the island was populated with creatures like pygmy elephants, colossal rats resembling the size of hares, and Komodo dragons.
The miniaturised human, often referred to as a “hobbit,” is believed to belong to the Homo floresiensis species, a scientific enigma ever since its first discovery 20 years ago. This recent archaeological find suggests that due to island isolation, this humanoid species may have experienced a rapid and significant shrinkage in physical scale, resulting from unique evolutionary stressors.
Dr Gert van den Bergh, a palaeontologist from the University of Wollongong in Australia and a contributor to this study, explained that island dwarfism was a familiar concept, linked for example to miniature versions of mainland megafauna inhabiting islands in the Mediterranean and Indonesia. He pointed out that the concept of island dwarfism in the animal kingdom was widely accepted, but when applied to human ancestors (hominins), people found it harder to embrace.
The lineage of the diminutive humans or “hobbits” has been a hotly contested topic since their initial discovery, with the first fossils unearthed being 60,000 years old. Opinions range from suggesting the presence of a unique disease causing stunted growth in a tribe of modern humans, to the possibility of links to an earlier petite, apelike species.
The recent unearthing supports the notion that these “hobbits” might have evolved from Homo erectus, or Java man, an ancestral human of comparable size to ourselves. This predecessor is believed to have become trapped on the island of Flores. The unearthed arm bone resembles the skeleton of previously discovered “hobbits,” and a pair of newly found teeth at the same location have similarities with Homo erectus teeth but are much smaller.
By examining the fossilised bone, researchers estimated the ancient humanoid’s height to be around 100cm, approximately 6cm less than the estimated height of a 60,000-year-old skeletal remains found 75km away on the same island.
Professor Adam Brumm of Griffith University’s Australian Research Centre for Human Evolution, who is also a co-author of a recently published paper, stated that a 700,000-year-old adult humerus discovered is not just smaller than that of the original Homo floresiensis. Instead, it is reportedly the tiniest upper arm bone discovered worldwide in the hominin fossil record. The rarity of the specimen, according to Brumm, affirmed the hypothesis that Homo floresiensis’ progenitors were minuscule in body size. It is now evident from this limb bone’s minuscule proportions that the ‘hobbit’s’ early precursors were even tinier than previously thought.
It’s popularly assumed that island dwarfism comes about because a lesser body size might provide a survival advantage during sustained food scarcity on islands – besides, larger size doesn’t provide much advantage as there are no large meat-eating mammals to deal with.
Several mysteries still need to be resolved, including how the forerunners of floresiensis first ended up on the island. Stone tools confirm that the island was inhabited as far back as 1 million years ago.
“There was a general belief that only current humans possessing boat technology would have managed to get to an oceanic island surrounded by extensive sea straits like Flores,” noted van den Bergh.
Meanwhile, Prof Chris Stringer, head of human origins at the Natural History Museum, who was not part of the study, remarked that the ability to follow a single evolving hominin lineage over such a timescale holds high expectations for prospective research.
“A lot of scientists presuppose that a dwarfing process took place on Flores itself, although it’s currently impossible to ascertain that. The process might have initially begun on other islands, like Sumbawa or Sulawesi before migrating to Flores,” added Stringer.
These research discoveries have been released in the Nature Communications journal.