You know when someone's Dad tries to be down with the kid's fashion and gets it horribly wrong? This seems like a pretty decent hypothesis for how this oddball came about. You can just picture the scene:
Wide plains, Middle Triassic period. A group of winged dinosaurs are huddled together. Enter SHAROVIPTERYX. DINO#1: Oh christ, who invited butt-wings? He's so weir- SHAR: Hey guys, what's up? DINO#1: Er, hey, Shar. We were actually just gonna go bowling. SHAR: Ohh, but the shoes don't fit on my awesome, wicked-cool feet. DINO#2: Gosh, that's a real shame. Well, see ya.
Some experts reckon that, with the addition of a wing on the forelimbs, the hind wings could actually have been a very efficient method of flight. This, however, seems a little unlikely due to the fact that the grand total number of other animals to have evolved this wing configuration is exactly zero - almost as though it's a wholly impractical place to keep your wings.
