Stingray (F. Dasyatidae)
Sentosa, 24th May 2008
I'm quite sure it's not a mangrove whipray (Himantura walga) or blue-spotted fantail ray (Taeniura lymma). However, there's something about the shape of the wings that makes me hesitate to identify it as a blue-spotted stingray (Neotrygon kuhlii). There are several other species of stingray known to occur in Singapore, but these are rarely encountered and very little is known about them.
On the other hand, it's possible that this belongs to one of the 3 common stingray species, just that the wings have shrunk or become distorted after death.
Wild Fact Sheets
Fishes of Libong Island
FishBase