The genus has been used to refer to large Western and Central European snake vertebrae from the Eocene.

[1] A species known from multiple well-preserved specimens found in the Messel Pit of Germany, P. fischeri, was named by Stephan Schaal in 2004, but examination of the genus showed that it represented a distinct lineage; it was renamed Eoconstrictor fischeri in 2020 by Agustín Scanferla and Krister T.

[2] Another species from France, P. filholii (named by Rochebrune in 1880), was moved to the genus Phosphoroboa in 2021 by Georgalis, Márton Rabi, and Smith.

[3] An additional species, P. sardus, was described in 1901 by Alessandro Portis from the Middle Miocene of Monte Albu (Sardinia, Italy).

[4] A new species, P. schaali, based on two complete skeletons from the Eocene of Messel, Germany, was described in 2022 by Smith and Scanferla..[5]