Pleurosternon

Pleurosternon is an extinct genus of freshwater pleurosternid turtle from the latest Jurassic to earliest Cretaceous of Europe. Its type species, P. bullockii, was described by the paleontologist Richard Owen (noted for coining the word Dinosauria) in 1853. Since then, and throughout the late 19th century, many fossil turtles were incorrectly assigned to this genus, though only two are currently considered valid.

==Taxonomy== Pleurosternon bullockii fossils were first described by Richard Owen in 1841 from specimens found in the earliest Cretaceous (Berriasian) aged Purbeck Group of the Isle of Purbeck, of Dorset in southern England, under the living genus Platemys. It was not until 1853 however, that it was published under the name Pleurosternon in a paper Owen presented to the Palaeontographical Society. P. portlandicum named by Richard Lydekker in 1889 from the latest Jurassic (Tithonian) aged Portland Stone of the Isle of Portland, Dorset, is now considered a junior synonym of the P. bullockii. In 2021 a second valid species, Pleurosternon moncayensis, was named from the Ágreda locality of Tarazona y el Moncayo, Aragon, Spain, which spans the Tithonian-Berriasian transition.