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Mmmm.. I looked at Loepa's pictures and decided to keep quiet for while. The similarity to your specimen (which I agree is Ephydridae) is due to convergent evolution - apart from being small, black and shiny, the elongate antennae are the only thing they share. Head shape, body shape and (especially) posture are all different. The posture of Loepa's flies bothers me most - no self-respecting ephydrid would ever wander around in that ridiculous way. :p
Camillidae seems like a good bet to me. Someone with access to a good world acalypterate collection should be able to spot this one. Are you awake, yet Steve?