not to mention the posture is different they stick the bum out into more of a sitting pose.
To finish the Idea, I have seen many, many, many videos on youtube of people that teach " Belly dance and Flamenco Fusion" and they market it every where. For the trained eyes it is clear that this people have not taken the time to study both discipline separtetly, this performances look very amateurish and it is obviously they only took a flamenco workshop and that was enough to start teaching the fusion.
I organized a flamenco teacher to take some classes when we were doing a flamenco/belly dance fusion piece (choreographed by somebody else). Apart from the fact that the Arabs occupied Spain some hundreds of years back ,there is little or no overlap. Hips, feet, arms all completely different.