[Paper] The affinities of Homo floresiensis based on phylogenetic analyses of cranial, dental, and postcranial characters

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This newly published paper by ANUs Debbie Argue has been making the news recently. A new analysis of the bones puts Homo floresiensis closer in time to Homo habilis than it does Homo erectus or Homo Sapiens, which suggests the the Hobbit’s lineage was more ancient than recent.

Although the diminutive Homo floresiensis has been known for a decade, its phylogenetic status remains highly contentious. A broad range of potential explanations for the evolution of this species has been explored. One view is that H. floresiensis is derived from Asian Homo erectus that arrived on Flores and subsequently evolved a smaller body size, perhaps to survive the constrained resources they faced in a new island environment. Fossil remains of H. erectus, well known from Java, have not yet been discovered on Flores. The second hypothesis is that H. floresiensis is directly descended from an early Homo lineage with roots in Africa, such as Homo habilis; the third is that it is Homo sapiens with pathology. We use parsimony and Bayesian phylogenetic methods to test these hypotheses. Our phylogenetic data build upon those characters previously presented in support of these hypotheses by broadening the range of traits to include the crania, mandibles, dentition, and postcrania of Homo and Australopithecus. The new data and analyses support the hypothesis that H. floresiensis is an early Homo lineage: H. floresiensis is sister either to H. habilis alone or to a clade consisting of at least H. habilis, H. erectus, Homo ergaster, and H. sapiens. A close phylogenetic relationship between H. floresiensis and H. erectus or H. sapiens can be rejected; furthermore, most of the traits separating H. floresiensis from H. sapiens are not readily attributable to pathology (e.g., Down syndrome). The results suggest H. floresiensis is a long-surviving relict of an early (>1.75 Ma) hominin lineage and a hitherto unknown migration out of Africa, and not a recent derivative of either H. erectus or H. sapiens.

Source: The affinities of Homo floresiensis based on phylogenetic analyses of cranial, dental, and postcranial characters

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Indians and Aboriginal Australians share genetic link

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Ok, not really news if you think about it – but good to have more corroborating evidence. This study (open access, too!) shows a distinct mDNA link between the aboriginal Australians and populations from the Indian subcontinent, which lends support to the idea that modern humans migrating out of Africa took a southernly route, hugging the coast, from India, through Southeast Asia and finally into Australia. Quite significantly, the divergence in the mDNA suggests that Australia was populated sometime around 50,000-60,000 years ago, which corresponds quite well to the conclusions derived from archaeology. This in turn implies that Southeast Asia was populated a little earlier, perhaps 70,000 years before present?

Uluru Sunset 2002
photo credit: Kiwi Flickr

Reconstructing Indian-Australian phylogenetic link
BioMed Central, 22 July 2009
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Bones tell story of Thai origin

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05 November 2006 (Bangkok Post) – DNA evidence for Thai migration to the region from China pushes timeline back another 700 years.

Bones tell story of Thai origin

The method constructed the so-called ”Phylogenetic tree” or ”genetic evolution tree” that indicates links between ancient skeletons and people in China and Southeast Asian countries, said Prof Samoerchai Poolsuwan, anthropologist from Thammasat University’s sociology faculty and also a member of the research team.

”The DNA test confirmed that the genes of the people and the skeletons are close,” he said.

”In lay terms, you may say that Thai ancestors may have shared the same ancestors from people in China and Southeast Asia.

”You may say that people in this region may share the same origins, and Thais may go back more than 700 years,” he said.

He said the findings are just a small part of the whole picture and more DNA tests were needed, adding the Fine Arts Department had agreed to use DNA tests at other archaeological sites.


Related Books:
Southeast Asia: From Prehistory to History by P. S. Bellwood and I. Glover (Eds)
The Excavation of Ban Lum Khao (The Origins of Civilization of Angkor, Vol. 1) by C. Higham