Gavialimimus Explained

Gavialimimus is an extinct genus of plioplatecarpine mosasaur from the Maastrichtian of Morocco and possibly Angola. It was a medium-sized mosasaur measuring around 6m (20feet) in total body length.^[1]

Discovery and naming

The holotype MHNM.KHG.1231, an articulated skull and associated fragmentary postcrania, was found in the Ouled Abdoun Basin. In 2023, a 4m (13feet) long specimen from Angola identified as Gavialimimus sp. was found within the guts of Prognathodon kianda.^[2]

The etymology of this genus means "gharial mimic" (Hindi Gavial = "gharial" + Greek mimus = "mimic"). The genus name refers to morphological convergence between Gavialimimus and the extant gharial (Gavialis gangeticus). Gavialimimus has been said to occupy the niche of a large piscivore. In this way, through severe specialization, it managed to co-exist with several other large mosasaur species in the same area.^[3]

Classification

In their 2024 description of the Moroccan plioplatecarpine Khinjaria, Longrich et al. used phylogenetic analyses to recover it within a clade of non-plioplatecarpin plioplatecarpine mosasaurids. They named this clade—also containing Gavialimimus, Goronyosaurus and Selmasaurus—the Selmasaurini.^[4] A similar clade was recovered by Strong et al. (2020) in their description of Gavialimimus. The results of the analyses of Longrich et al. are shown in the cladogram below:

Notes and References

1. S.L.A.. Cooper. K.J.. Marson. R.E.. Smith. D.. Martill. 2022. Contrasting preservation in pycnodont fishes reveals first record of regurgitalites from the Upper Cretaceous (Maastrichtian) Moroccan phosphate deposits. Cretaceous Research. 131. 4. 105111. 10.1016/j.cretres.2021.105111.
2. Book: Polcyn, Michael J. . Schulp . Anne S. . Gonçalves . António O. . Lee, Y.-N.. 2023 . Remarkably well-preserved in-situ gut-content in a specimen of Prognathodon kianda (Squamata: Mosasauridae) reveals multispecies intrafamilial predation, cannibalism, and a new mosasaurine taxon . Windows Into Sauropsid and Synapsid Evolution . Dinosaur Science Center Press . 66–98 . 978-89-5708-358-1 .
3. Strong. Catherine R. C.. Caldwell. Michael W.. Konishi. Takuya. Palci. Alessandro. 2020-09-28. A new species of longirostrine plioplatecarpine mosasaur (Squamata: Mosasauridae) from the Late Cretaceous of Morocco, with a re-evaluation of the problematic taxon Platecarpus ptychodon. Journal of Systematic Palaeontology . 18 . 21 . 1769–1804 . 10.1080/14772019.2020.1818322.
4. Longrich . Nicholas R. . Polcyn . Michael J. . Jalil . Nour-Eddine . Pereda-Suberbiola . Xabier . Bardet . Nathalie . 2024-03-01 . A bizarre new plioplatecarpine mosasaurid from the Maastrichtian of Morocco . . 105870 . 10.1016/j.cretres.2024.105870 . 0195-6671.