This is probably the oldest living dragonfly family. Fossil records of petaltails go back to the Jurassic period, 150 million years ago.

This family includes the largest species of dragonfly, the giant Petaltail (Petalura ingentissima). The giant petaltail is found in Australia and has a wingspan of six inches.

There are two species in this family found in the United States, the gray petaltail (Tachopteryx thoreyi) and the black petaltail (Tanypteryx hageni).

The gray petaltail is found in the eastern United States, and the black petaltail is found in the western United States.