Thursday, 31 March 2016

Hobbits in the headlines again

Liang Bua, the cave where Homo floresiensis was found.
This image was originally posted to Flickr by Rosino (CC-BY-SA-2.0).
When a new hominin was described from Flores in Indonesia (here), it was quickly dubbed "hobbit" with reference to its small stature (1.1 m) and relatively large feet. Even more sensational, however, was the date of 15 thousand years ago (kya) based on charcoal from the same deposit. The implication was that the "hobbit" (Homo floresiensis) overlapped in time with our own species.

Yesterday my Twitter feed lit up with news of a paper (here) that drastically revised the age of these fossils to between 60-100 kya. Briefly there had been slippage of more recent material, including charcoal, into an eroded area where the bones were found. The new study used several methods to obtain the earlier date. Unlike in the original report, these included dating of the bones themselves.
Skull of Homo floresiensisThis image was originally posted to Flickr (CC-BY-SA-2.0).
The new dates match those of stone tools ranging from 50-190 kya. The most recent of those dates corresponds with the arrival of H. sapiens in the region, leading to conjecture that this caused the demise of the "hobbits."

There is a new flurry of speculation about the origin of this species. One idea (discussed here) is that it is derived from Homo erectus (previous post) and its small stature is an example of Island Dwarfism (as seen in pygmy elephants from Flores and pygmy hippopotami from Madagascar).

Flores lies East of the Wallace Line, a water barrier that separates the Southeast Asian and Australasian flora and fauna (previous post). It seems not to have presented a barrier to hominins. The enigmatic Denisovans also crossed the Wallace Line (previous post).

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