The only fossil specimen of Sharovipteryx mirabilis
Sharovipteryx mirabilis is one of the odder creatures to be found in the fossil record notable because it seems to have wings on it's hind limbs which seems to be a unique adaptation.
A new paper is in press in the Journal of Evolutionary Biology that proposes a model of how this strange beast would have flown. Their reconstruction is shown below. I have no idea if this is actually what the creature would have looked like but it seems like a fairly logical interpretation of the fossil.
Flight of Sharovipteryx mirabilis: the world’s first delta-winged
glider. G. J. DYKE, R. L. NUDDS & J. M. V. RAYNER. Journal evolutionary biology (in press) doi:10.1111/j.1420-9101.2006.01105.x