Polysternon
Polysternon is a genus of turtles in the extinct family Bothremydidae. It was described by Portis in 1882, and contains the species P. provinciale, which existed during the Cretaceous of what is now France and a new species, P. isonae, from the Late Maastrichtian of Spain.
The species epithet of P. isonae refers to the municipality Isona i [Conca Dellà] in Catalonia, where the type specimen was discovered in the Tremp Formation.