Well, when a feature appears and then disappears, that's called a reversal, too, isn't it?
Well, most flightless birds don't need grasping hands. And those that needed them might have had them to some extent... Titanis?
To be precise, phylogenetic bracketing: It's normal for vertebrates to have 4 types of cones in the retina, for red, green, blue and ultraviolet. Mammals never have the last as far as is known, and all except some primates (e. g. us) don't have the first either -- to be red-green-blind is a synapomorphy of mammals. In those that have a red one it is clearly a recent, slightly altered copy of the green one (the gene got duplicated).
That something dis- and then reappears? I can't, at least at the moment.