Leptosynanceia is a monotypic genus of ray-finned fish belonging to the subfamily Synanceiinae, the stonefishes, which is classified within the family Scorpaenidae, the scorpionfishes and relatives, its only species is Leptosynanceia asteroblepa which is called the mangrove stonefish in Malaysia.

This species is an extremely dangerous fish whose venom can cause a human to die within 1 to 2 hours after contact.

[5] However, other authorities regard Synanceiidae as a valid family and the Synanceiini as the subfamily Synanceiinae.

[6] Leptosynanceia has an almost vertical mouth, its eyes are place on the dorsal surface of its head and direct outwards and upwards.

[1] The colour is pale brown, slightly paler ventrally with a mottled head and darker blotches on the body.