The oldest described pliosaurus reexamined

Ischyrodon meriani is an obscure pliosaurid taxon from the Middle Jurassic of Switzerland. Despite being described in 1838, which likely makes it the historically oldest-established pliosaurid, the type specimen of Ischyrodon remains poorly researched. The new study presents a detailed redescription of I. meriani and shows its close resemblance to Liopleurodon ferox which originates from strata of a similar age and provenance. While it is likely that I. meriani represents a Liopleurodon-like taxon, or is even conspecific with L. ferox, which would make I. meriani the proper name for the species, any such taxonomic considerations are hindered by the fragmentary nature of the type specimens of both these taxa. The new study highlights the need for a detailed taxonomic reevaluation of Liopleurodon ferox.