Phlegethontia is an extinct genus of aïstopod tetrapodomorphs from the Carboniferous and Permian periods of Europe and North America.

[1] It was about 1 metre (3.3 ft) long, and possessed a lightly built skull with many openings, unlike some earlier relatives.

[2] "Dolichosoma" longissima, named by Antonin Fritsch in 1875, has been reassigned to the genus Phlegethontia and is now considered to be P.

[3][4] "Dolichosoma" has been considered to be a nomen nudum because the holotype was inadequately described through a layer of matrix by Thomas Henry Huxley in 1867.

This article about a tetrapodomorph is a stub.