Genus: Pannoniasaurus MAKADI, CALDWELL & OSI, 2012
Etymology: From ancient Roman province, Pannonia, in the Transdanubian part of Hungary, and New Latin word from Greek, sauros, 'lizard'.

Species: inexpectatus MAKADI, CALDWELL & OSI, 2012
Etymology: Latin, inexpectatus, 'unexpected'; referring to the unexpected occurrence of this mosasaur in freshwater environments.

Holotype: MTM 2011.43.1

Locality: Iharkut open-pit bauxite mine, Bakony Hills, Western Hungary.

Horizon: Csehbanya Formation.

Biostartigraphy:

Age: Santonian Stage, Lower Senonian Subepoch, Lower Gulf Epoch, Late Cretaceous.

Material: Isolated right quadrate.

Referred material:

MTM Gyn/116. dorsal vertebra (pathologic).