For tough questions like this, and for role-in-the-argument questions in general, I try to relate everything to the conclusion. In this case, the conclusion is that the paleobiologist must be wrong. Once you identify the conclusion, this is just an exercise in finding how the statement relates to the conclusion. Since we know that this is a point that the author iuses to support the conclusion, it is a premise. The author is not trying to refute the claim that Dinos didn't have turbinates.
In general, regarding speed, I think the best thing you can do is get really good at finding the main point. For that, I would recommend main point question office hours, and drilling in your analytics tab.