I dont want to pollute this thread, but want to briefly describe my time (mid 2000s) as an undergrad with half a double-major in US anthropology. I was on several occasions warned-off from doing projects that pertained to this very subject and a couple others [examples: h. neanderthalensis relation to modern humans (at the time in the face of mtDNA), some other N. American immigration hypotheses (eg, that pleistocene…
Not to dismiss your experiences with academic anthropology, but this paper isn't actually about any transoceanic seafaring cultures. It's about the population structure of some of the first peoples of the Americas and their ancestors, which predate polynesians by something like ten to twenty thousand years. I made the same mistake on my initial reading too.
This is not the venue to parse out what Australasian means, but, at least genetically, we would be discussing a much older population.
It is by definition about seafaring people, however, as the only accepted migration path to the americas has been over the bering straights.
edit: oops. now i see where you are coming from. Mea culpa. see comment re Pleistocene boats. Apologies for my derp