I had thought of atavism as meaning genetic recombination and really hadn't seen it used in general literature. However, I came across it in the U. of Chicago Law magazine, used this way: "I'm appalled at the argument used by Justice Scalia to support his view that the death penalty is morally acceptable. I consider his Bible quoting to be primitive and atavistic nonsense". Then I checked Google and found it used when describing a poem. Interesting word! How have you seen it used?
Yes, Asa, you're right; atavism means a throwback. However, isn't "luddism" more specific in that it means the opposition of technological change? Or, can it be used more generally?
I was asking someone about "atavism" today, and he said that he always mixed it up with "avatar". Now, that was a new word for me. It means the incarnation of a Hindu deity in human or animal form. However, from AHD, it also can be more general, meaning an embodiment, thus making it a bit more useful; for example, "the very avatar of cunning".
I got a definition from an online databank of words that sez that atavism is, "The return of a trait or recurrence of previous behavior after a period of absence." so I suppose that throwback might be close. Would that make stone crabs atavistic?