Gavialimimus
Gavialimimus is an extinct genus of plioplatecarpine mosasaur from the Maastrichtian of Morocco and possibly Angola.
Discovery and naming
In 2020, Strong and colleagues named a new genus of plioplatecarpine mosasaur Gavialimimus based on the specimen MHNM.KHG.1231, an articulated skull and associated fragmentary postcrania found in the Ouled Abdoun Basin, which was designated as the holotype. The etymology of this genus means "gharial mimic", referring to morphological convergence between Gavialimimus and the extant gharial. The specific name almaghribensis references al-Maghrib, the type locality of Gavialimimus. In 2022, Longrich and colleagues reported various marine vertebrate remains with signs of acid damage including a rostrum assigned to G. almaghribensis found in close vicinity to Thalassotitan, suggesting that these fossils are digested by the stomach acid of a large mosasaur like Thalassotitan.In 2023, Polcyn, Schulp and Gonçalves described the gut contents of a long mosasaur specimen identified as Prognathodon kianda from Angola, which preserved three species of mosasaurs: a long specimen of Gavialimimus sp., a small individual of P. kianda and a new taxon Bentiabasaurus. The size of Gavialimimus sp. was about 57% the size of P. kianda, and most of the gut contents of P. kianda were cranial material, suggesting that Prognathodon preferred to consume the head portion of other mosasaurs including relatively large taxa and its own kind.
Synonymy with "''Platecarpus''" ''ptychodon''
"Platecarpus" ptychodon is another plioplatecarpine mosasaur from the same locality, which was described by Camille Arambourg in 1952 based on an isolated tooth MNHN PMC 30 and other referred specimens. Other specimens were referred to "P." ptychodon including a tooth specimen and a more complete skull, which led Bardet et al. to recognize that "P." ptychodon is not a species of Platecarpus, though no taxonomic revisions were made.Although Strong et al. acknowledged the similarity between the fragmentary holotype tooth of "P." ptychodon and the holotype of G. almaghribensis, they considered "P." ptychodon to be a dubious, undiagnostic taxon. In a comprehensive 2025 study of mosasaur teeth from the Maastrichtian of Morocco, Bardet and colleagues found the type specimen of "P." ptychodon to be diagnostic and distinct from teeth of all other mosasaurid species except for G. almaghribensis. Thus, they considered "P." ptychodon to be a senior synonym of G. almaghribensis, proposing the new combination G. ptychodon.
Bardet et al. also mentioned unpublished specimens and assigned OCP DEK/GE 356 and OCP DEK/GE 560 to their proposed combination. They also referred a vertebra, which was previously assigned to another extinct marine squamate Pachyvaranus from the same locality.