re: Prolly.
"recorded dust devils appear to leave no tracks or barely perceptible ones in Gusev."
Actually - the opposite is true. They are very hard to spot ( because they are being seen very 'edge on' as it were . But not only can you see a track forming in that very animation you post, but you can see near a crater called, iirc, Missoula crater, when you're close enough to a dust devil track - that they do indeed make dark tracks.
http://marsrovers.jpl.nasa.gov/gallery/press/spirit/20040428a.html