Petaluridae
The petaltails of the family Petaluridae are apparently the most ancient of the extant true dragonflies, having fossil members from as early as the Jurassic.
Modern petalurids include only 11 species, one of which, the Australian Petalura ingentissima, is the largest of living dragonflies, having a wingspan of up to 160 mm and a body length of over 100 mm. Other Australian species include Petalura gigantea. In the United States, two species are found, one on either coast. The larvae live primarily in stream banks, mostly in burrows, but the larvae of the eastern US species, Tachopteryx thoreyi, the gray petaltail, live in depressions under wet leaves. The semiaquatic habitat of the larvae makes the petaltails unique in the modern dragonfly families.
