On the Heels of the Discovery of Homo luzonensis...

A new study from the journal Cell suggests that there were multiple migrations of individuals into Southeast Asia with the Denisovan genome.  Here is the summary from Cell.

Genome sequences are known for two archaic hominins—Neanderthals and Denisovans—which interbred with anatomically modern humans as they dispersed out of Africa. We identified high-confidence archaic haplotypes in 161 new genomes spanning 14 island groups in Island Southeast Asia and New Guinea and found large stretches of DNA that are inconsistent with a single introgressing Denisovan origin. Instead, modern Papuans carry hundreds of gene variants from two deeply divergent Denisovan lineages that separated over 350 thousand years ago. Spatial and temporal structure among these lineages suggest that introgression from one of these Denisovan groups predominantly took place east of the Wallace line and continued until near the end of the Pleistocene. A third Denisovan lineage occurs in modern East Asians. This regional mosaic suggests considerable complexity in archaic contact, with modern humans interbreeding with multiple Denisovan groups that were geographically isolated from each other over deep evolutionary time.

These data, in combination with the new Luzon material further suggest that the population interrelationships in Southeast Asia were complex, with considerable mixing between Denisovans, archaic Homo sapiens, eastward-migrating Neandertals and who knows how many other groups. We know from the material in China that the fossil material of even 100 thousand years back exhibits multiple origins.  As I noted about the Xuchang hominins at the time:

These two Chinese skulls stand at the crossroads of these population movements. While showing clear Neandertal characteristics, they also express modern traits, possibly reflecting mixing with the late, modern human arrivals represented by the recent modern human finds at Daoxian. Yet they also express a clear link to ancient East Asian populations. The implications of these skulls are stark: there has been widespread population mixing and regional continuity in Europe and Asia for at least 400 thousand years. Not only did the Neandertals feel enough cultural kinship to mate and have children with these East Asian people, the early modern humans coming out of Africa did, as well. As Chris Davis of China Daily News put it: “One big happy family.”

The presence of the hominins in Luzon, as well as the new research reported here suggests that this complexity comprised all of East Asia.

New Species of Hominin Found in Phillipines

From a story in UPI:

At the completion of excavations on the island of Luzon, scientists had unearthed several teeth, part of a thigh bone, and a few hand and foot bones. The fossils comprise the "the earliest direct evidence of a human presence in the Philippines," according to the latest study.

The fossilized bones, dated to between 67,000 and 50,000 years ago, feature a mix of anatomical characteristics, some that recall more primitive hominins and others similar to those of more modern human species.

Callao Cave is toward the northern tip of Luzon. The corresponding article from Nature seems to indicate that the fossil remains from this cave are “all over the map.”  The premolars indicate size and shape affinities to later Homo, while some of the characteristics are australopithecine (!).  This is also true of the hand elements. 

Although we have found human fossil remains in East Asia for some time (1896 on), there are large gaps in our knowledge, especially from the first appearance of Homo erectus to the advent of modern humans.  These fossils, while giving us more  information than we had, muddy the waters a bit.  Once upon a time, Grover Kranz (RIP) tried to convince me that australopithecines could be found in East Asia, but his evidence was based on a badly crushed occipital bone. 

It is clear from the presence of H. floresiensis and the current evidence that primitive traits were being retained in some groups but, as the authors point out, we need quite a bit more fossil material to make any definitive assessments.