An archaeological study led by an Australian National University (ANU) researcher shows that Homo floresiensis, a species of tiny human discovered in Indonesia in 2003, most likely evolved from an ancestor in Africa, the ANU on Friday reported.
Homo floresiensis, dubbed the “hobbits” due to their small stature, were discovered on the Indonesian island of Flores in 2003.
The study led by Dr Debbie Argue from the ANU School of Archaeology & Anthropology found that Homo floresiensis were most likely a sister species of Homo habilis, one of the earliest known species of humans found in Africa 1.75 million years ago.
Previously, a popular theory argues that Homo floresiensis evolved from the much larger Homo erectus, the only other early hominid known to have lived in the region with fossils discovered on the Indonesian mainland of Java.
Data from the study concluded there was no evidence for that theory in spite of its popularity.
Argue said none of the data supported the theory that Homo floresiensis evolved from Homo erectus.
Rather, the analyses show that on the family tree, Homo floresiensis was likely a sister species of Homo habilis.
“It means these two shared a common ancestor,” Argue said.
“It’s possible that Homo floresiensis evolved in Africa and migrated, or the common ancestor moved from Africa then evolved into Homo floresiensis somewhere.”
Homo floresiensis is known to have lived on Flores island until as recently as 54,000 years ago.
Where previous research had focused mostly on the skull and lower jaw, this study used 133 data points ranging across the skull, jaws, teeth, arms, legs and shoulders.
Argue said the research team looked at whether Homo floresiensis could be descended from Homo erectus and found that “if you try and link them on the family tree, you get a much unsupported result.’’
“All the tests say it doesn’t fit – it’s just not a viable theory.”
Argue said this was supported by the fact that in many features, such as the structure of the jaw, Homo floresiensis was more primitive than Homo erectus.
“Logically, it would be hard to understand how you could have that regression – why would the jaw of Homo erectus evolve back to the primitive condition we see in Homo floresiensis?”
Argue said the analyses could also support the theory that Homo floresiensis could have branched off earlier in the timeline, more than 1.75 million years ago.
“If this was the case Homo floresiensis would have evolved before the earliest Homo habilis, which would make it very archaic indeed,” she said.
Prof. Mike Lee of Flinders University and the South Australian Museum used statistical modeling to analyse the data.
“When we did the analysis there was really clear support for the relationship with Homo habilis. Homo floresiensis occupied a very primitive position on the human evolutionary tree,” Prof. Lee said.
“We can be 99 per cent sure it’s not related to Homo erectus and (there is a) nearly 100 per cent chance it isn’t a malformed Homo sapiens,” Lee said.
Dr Argue undertook the study along with ANU Professor Colin Groves, and Professor William Jungers from Stony Brook University, USA.
The findings have been released in the Journal of Human Evolution.