 |
| Gavialimimus almaghribensis Strong, Caldwell, Konishi & Palci, 2020 |
Abstract
The Upper Cretaceous phosphates of Morocco preserve one of the world’s most diverse assemblages of mosasaurs, reflecting the adaptive radiation of this clade during the Maastrichtian. Herein, we describe a new mosasaur from these deposits. Although the teeth of this specimen resemble those of ‘Platecarpus’ ptychodon, suggesting referral to this species, we re-examine and ultimately reject the fundamental validity of ‘P.’ ptychodon due to the non-diagnostic nature of its holotype and original diagnosis. We instead designate the new specimen as the holotype of a new genus and species, Gavialimimus almaghribensis, gen. et sp. nov. G. almaghribensis is characterized by a highly elongate snout, highly retracted nares and large supratemporal fenestrae, among other features. Phylogenetic analysis under multiple parsimony-based methods reveals novel substructure within the subfamily Plioplatecarpinae, consistently recovering a clade uniting the new species with Selmasaurus and the enigmatic Goronyosaurus. Synapomorphies of this clade include a highly constricted parietal, with Selmasaurus and Gavialimimus being further united by a broadly excavated medial surface of the quadrate suprastapedial process. The cranial morphology of G. almaghribensis also provides new insight into several aspects of mosasaur evolution and comparative anatomy, including adaptive radiation and niche partitioning in Moroccan marine palaeoecosystems.
Keywords: adaptive radiation, functional morphology, niche partitioning, palaeoecology, taxonomic revision, vertebrate palaeontology
 |
| Life reconstruction of Gavialimimus almaghribensis, gen. et sp. nov., hunting a school of teleosts. Illustration: Tatsuya Shinmura. |
Systematic palaeontology
Reptilia Linnaeus, 1758
Squamata Oppel, 1811
Mosasauridae Gervais, 1852
Plioplatecarpinae (Dollo, 1884) Williston, 1897
Gavialimimus gen. nov.
Derivation of name. Meaning ‘gharial mimic’, from the
Gallicized Hindi root ‘gavial’ and the Greek root
‘mimus’, the genus name refers to morphological convergence between the holotype specimen and the extant
gharial (Gavialis gangeticus), primarily regarding their
distinctive longirostry and interlocking teeth.
Gavialimimus almaghribensis sp. nov.
Derivation of name. The specific epithet is a romanized
version of the Arabic name for Morocco [al-Maghrib], paired with
the Latin suffix ‘-ensis’, thus denoting the country of
origin of the holotype.
Occurrence. Upper Couche III (upper Maastrichtian) of
the Oulad Abdoun Basin in northern Morocco
Catherine R. C. Strong, Michael W. Caldwell, Takuya Konishi and Alessandro Palci. 2020. 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. DOI: 10.1080/14772019.2020.1818322
