You seriously believe Australian Aborigines are as intelligent as the Japanese?
I seriously believe nobody knows. I doubt the question makes sense, actually. Certainly IQ tests as currently administered and evaluated do not settle the question.
And I seriously believe that neither the Australian Aborigines or the Japanese are a "race" - although I could be argued into such a classification by a rigorous racial classification protocol that delivered such a result from its handling of the species generally - note that such a classification system would not deliver anything like the current US sociological races (for starters there would be maybe seven "black" races and three "yellow" ones, and some of them would include white-skinned people).
Shared ancestry, like any other taxa in biology.
That's not how taxa in biology are defined.
Meanwhile: No human race has been defined by shared ancestry, or any other scientific classification method. Human races are defined by social custom and circumstance, usually by sociologically significant aspects of culture or appearance, especially skin color. They vary by society, and time, and geographic region (for example: the Irish were "black", racially, in the US, until about 1840).
Do you think race IQ hasn't been tested?
I know it hasn't. No IQ testing protocol of any major sociological group has ever included a valid correction of its results for a single one of the dozens of environmental and sociological circumstances known to affect IQ scores.
Humans are a subspecies, not a species or a race. They can be divided into races, which are infrasubspecific.
Currently extant humans are biologically classified as one species - Homo sapiens
https://en.wikipedia.org/wiki/Homo_sapiens.
Maybe, in theory, the one species could be divided into biological races, but it has not been so divided. Nobody has done that yet.
Infrasubspecific is a goofy term - where are you getting this bs from?