What is "synthemistidae"

The Synthemistidae are the family of dragonflies commonly known as tigertails, or sometimes called southern emeralds. This family has seven genera and 43 species; they look 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. Their nymphs 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.