If you're categorizing fallacies as sub-fallacies of others, the Appeal to Authority would be a sub-fallacy of the Genetic Fallacy. It is used when experts are cited that are not experts in the subject at hand.
Curt: Warren Buffet is the richest man in the world, and he says that Vitamin-D3 supplements reduce your chances of getting cancer.
Michelle: I've never heard that before, but Warren Buffet is obviously a savvy guy, so I guess that's not so hard to believe.
Curt is appealing to Warren Buffet on a matter of nutrition, when Buffet's expertise is in business and finance. This is a faulty Appeal to Authority.
This fallacy is very common. People appeal to movie stars, politicians, and know-it-all uncles all the time. Appealing to a movie star in an argument about the best technique for remembering ones lines in an Off-Broadway play would be a legitimate appeal to authority, because they clearly have experience to know what they are talking about. Appealing to them to argue the best way to reduce deer overpopulation in Wisconsin lake country would be fallacious. They are welcome to their opinion, as is anyone, but they probably don't have experience with deer populations, and so they lack expertise.
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