Plagiophthalmosuchus
Plagiophthalmosuchus is an extinct genus of thalattosuchian crocodylomorph from the Early Jurassic Whitby Mudstone Formation of Whitby, Yorkshire, UK, and Dudelange, Luxembourg. It contains the single species Plagiophthalmosuchus gracilirostris. In life, it was a small marine predator that would have fed on fish.
History
The type species, P. gracilirostris, was originally named as a species of Teleosaurus in 1836, but then it was moved to the different genus Steneosaurus in 1961 Steneosaurus was used as a longtime wastebasket taxon for various teleosauroid specimens and had more than a dozen species. The type species, Steneosaurus rostromajor is undiagnostic, making the genus dubious and invalid. Additionally, many species of so-called "Steneosaurus" were found to be quite different and unrelated to one another, thus needing new generic names.In 2020, Michela Johnson and colleagues reassigned "Steneosaurus" gracilirostris to the new genus Plagiophthalmosuchus, resulting in the new combination Plagiophthalmosuchus gracilirostris. The generic name translates to "lateral-eyed crocodile" in reference to the position of the animal's eyes on its skull.
Classification
When Plagiophthalmosuchus was recognized as its own genus in 2020, it was found to be the most basal member of the group Teleosauroidea. Teleosauroids were a group of crocodylomorphs that were adapted for spending most of their lives out at sea. This group contains two main families, the more gracile and fish-eating Teleosauridae and the more macropredatory and robust Machimosauridae.The cladogram below is from the 2020 analysis by Johnson and colleagues.
A later study in 2024 by Mark Young and colleagues found Plagiophthalmosuchus to be outside of Teleosauroidea, instead as one of the most basal thalattosuchians.