The petaltails of the family Petaluridae are apparently the most ancient of the extant true

dragonflies A dragonfly is a flying insect belonging to the infraorder Anisoptera below the order Odonata. About 3,000 extant species of true dragonfly are known. Most are tropical, with fewer species in temperate regions. Loss of wetland habitat threa ...

(infraorder Anisoptera), having

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

members from as early as the

Jurassic The Jurassic ( ) is a geologic period and stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The Jurassic constitutes the middle period of ...

(over 150 million years ago). Protolindenia wittei 1

Modern petalurids include only 11 species, one of which, the Australian ''

Petalura ingentissima ''Petalura ingentissima'', the giant petaltail, has been described as the world's largest dragonfly, with a wingspan of 160 mm. It is found in Queensland, Australia. Dr R.J. Tillyard described the giant petaltail in 1908. Its species name i ...

'', 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 ''Petalura gigantea'', the giant dragonfly or south-eastern petaltail, is one of the world's largest dragonflies, with the males having an abdomen 6-7.5 cm long and a wingspan up to 11 cm, while females have an abdomen 8-9.5 cm lo ...

'' (commonly known as the giant dragonfly). In the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...

, 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 ''Tachopteryx thoreyi'', commonly known as the gray petaltail and Thorey's grayback, is a species of dragonfly. It is native to the East Coast of the United States as far north as New York, as far south as Florida, and as far west as Texas. This ...

'', the gray petaltail, live in depressions under wet leaves. The semiaquatic habitat of the larvae makes the petaltails unique in the modern dragonfly families.

Notes

References

*Silsby, Jill. 2001. ''Dragonflies of the World''. Smithsonian Institution Press, Washington D.C. * Aeshnoidea Odonata families Odonata of North America Odonata of Australia Taxa named by James George Needham Insects described in 1903 {{Aeshnoidea-stub