The Synthemistidae are the family of dragonflies commonly known as tigertails, or sometimes called southern emeralds. Synthemistidae has seven genera and 43 species. These dragonflies looks similar to corduliid and gomphid dragonflies. This family is sometimes treated as a subfamily of Corduliidae. This is an ancient dragonfly family, occurring in Australia and New Guinea. Most species are small in size and have narrow abdomens. The nymphs of these dragonflies are bottom-dwellers, and resist droughts by burying themselves very deeply. Synthemistid dragonflies frequently prefer marshy areas, as well as fast-flowing streams. The family Synthemistidae is sometimes called Synthemidae.