Ancient DNA is providing transformative insights into the journey of hominin evolution. Palaeontologists and geneticists have uncovered a branching mosaic picture of hominin ancestors.

No longer is the linear, single line from transitional forms to Homo sapiens the dominant image. However, digging up old bones and identifying fossils is still the sure fire way of advancing our understanding of human evolution, and steadily filling in the multi branching picture of our hominin ancestors.

Homo floresiensis, so-called ‘hobbits’, were first identified in 2003 from fossils in Liang Bua cave on the Indonesian island of Flores. The latter is an island between Australia and south east Asia. Approximately 3 feet six inches tall, they made stone tools, and while they had small brains, they coped with predatory pressures and may have even used fire. The findings were publicised in 2004.

Being diminutive, scientists were unsure at first if they were indeed a separate hominin species, or a badly deformed human. Some palaeontologists suggested they were descended from Australopithecus afarensis – Lucy’s species. (That discovery was made fifty years ago this year).

Other scientists have more plausibly suggested that Homo floresiensis is a descendant, dwarfed in stature, from the nearby Asian Homo erectus, from Java. Short and stocky in stature, the fossils of the now extinct homo erectus have largely been found in Indonesia and China.

Ok, let’s pause here and get a pet peeve out of the way.

Let’s stop calling Homo floresiensis ‘hobbits’. The fictional characters from the Lord of the Rings trilogy are very entertaining, to be sure, but they are a distraction from the serious issue of ancestral hominin evolution.

Africa – and China – have a wealth of hominin fossils. East African nations, such as Ethiopia, Kenya and Tanzania became famous in the 1970s for the multiple fossil finds that threw open the doors, so to speak, on early hominin evolution. The Leakeys, both Louis and Mary, became celebrity fossil hunters of sorts, giving lectures and writing books about paleoanthropology. Their son, Richard Leakey, who passed away in 2022, followed in his parents’ footsteps, and became a prominent anthropologist in his own right.

Indonesia is not a place you would think of as having fossils of interest to palaeontologists, but yet it does. The discovery of Homo floresiensis was significant because it further buttressed the picture of humans sharing the world with other hominin species.

The floresiensis find also demonstrated a singularly interesting case of island dwarfism. Did the floresiensis species arrive on the island as dwarves, or did they undergo endemic dwarfism? Numerous researchers have sought to answer this question, by examining how an isolated species with no predators to defend against on an island, could undergo rapid dwarfism.

This question is steadily being answered, and while interesting, represents a first step. This brings us to a recent and important fossil discovery on the Flores island.

East of the original 2004 findings in Liang Bua cave, a region called Mata Menge, a tiny upper arm bone was discovered in the So’a Basin. The adult humerus, along with fossilised bones and teeth found in 2016 in Mata Menge, indicate an adult of no more than 100cm in height – an ancestor shorter than Homo floresiensis.

Along with the upper arm bone, two fossilised teeth were discovered, and this dentition ties the floresiensis species more closely to Homo erectus ancestors. Teeth provide all sorts of information about the taxonomy of the ancestral species, as well as evidence of function.

It is worthwhile to note that the original researchers of 2003-04 did not actually set out to discover a new ancestral hominin species. They were attempting to answer how ancient people traveled from mainland Asia to Australia. Digging in caves, such as Liang Bua in Indonesia, provides essential clues as to how and by what route the migration occurred.

Indeed, there is a growing body of evidence from West Papua – specifically the Raja Ampat archipelago – which indicates the route of ancient seafarers from Asia into the Pacific islands. These mariners became the ancestors of indigenous people across West Papua to Aotearoa New Zealand.

Homo floresiensis is extinct, but its impact is still being felt today. That is because it helped revolutionise the way we think about human evolution. It is not a simple, linear progression, but a multi networking branching web of life. Ancient DNA has only added to the complex mosaic of ancestral hominins. There was no single ‘garden of Eden’, not in Africa or the Middle East. It is the ongoing and changing story of migratory ancestral hominins that makes human evolution the greatest story ever told – one that is currently unfolding.