Prognathodon

Prognathodon is an extinct genus of marine lizard belonging to the mosasaur family. It is classified as part of the Mosasaurinae subfamily, alongside genera like Mosasaurus and Clidastes. Prognathodon has been recovered from deposits ranging in age from the Campanian to the Maastrichtian in the Middle East, Europe, New Zealand, and North America. Prognathodon means "forejaw tooth", which originates from the Latin pro- ("earlier" or "prior"), Greek gnathos ("jaw") and odṓn ("tooth"). Twelve nominal species of Prognathodon are recognised, from North America, northern and western Africa, the Middle East, western Europe and New Zealand. Due to the sometimes clear differences between them and the incomplete nature of many of the specimens, the systematics of the genus and which species should properly be considered Prognathodon is controversial. Some species have been assigned to other genera, such as Dollosaurus and Brachysaurana, but this has also been questioned. Prognathodon is known for its massively built jaws and teeth. Its distinct feeding adaptations have generated much interest in its ecology ever since its discovery, though direct evidence of its diet, such as gastric residues, is rare. Prognathodon was first described by Louis Dollo in 1889 based on specimens gathered in Belgium. There is some confusion over the correct generic name for the taxon. Dollo first mentioned the taxon as "Prognathodon" in some preliminary notes and provided a provisional diagnosis, but replaced the name Prognathodon with "Prognathosaurus" and used Prognathosaurus in all of his subsequent papers mentioning the genus. The first later use of "Prognathodon" was by Dale A. Russell in a comprehensive monograph on North American mosasaurs in 1967, where the priority of Prognathodon was made apparent. Russell also revised the species assigned to Prognathodon from North America , but only briefly commented on the Belgian specimens. Though the original remains of the genus were rather comprehensive and the original description was brief, no additional studies of the type material was done for a century.