What is a research librarian?

I decided that as I have been giving this a lot of thought for the South African context, I'd surf, crawl, trawl and whatever else to see whats out there. Its interesting how the terms 'reference librarian'; 'research librarian' and other terms have been used interchangeably. I wonder if it is just a case of whats in a name or a matter of degree of activity or task specificity? I tend to think it might be feasible to separate these terms out to some extent wihtout being elitist. Research librarian appears to refer more to the academic librarian and specialist librarian but not exclusively. I believe that in SA we are a bit of both research and reference librarian, probably erring more on the side of the reference librarian. I have yet to develop this idea.