Pluridens serpentis, a new mosasaurid (Mosasauridae: Halisaurinae) from the Maastrichtian of Morocco and implications for mosasaur diversity - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Cretaceous Research Année : 2021

Pluridens serpentis, a new mosasaurid (Mosasauridae: Halisaurinae) from the Maastrichtian of Morocco and implications for mosasaur diversity

Nicholas R Longrich
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Fatima Khaldoune
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Oussama Khadiri Yazami
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Résumé

Mosasaurids (Mosasauridae) were specialized marine lizards that evolved and radiated in the Late Cretaceous. Their diversity peaked in the 23 Maastrichtian, with the most diverse faunas known from Morocco. Here we describe a new species of mosasaurid from this fauna. Pluridens 24 serpentis sp. nov. is described based on two complete skulls and referred jaws. It is referred to Pluridens based on the elongate and robust jaws, 25 small teeth, and specialized tooth implantation. Pluridensis referred to Halisaurinae based on the posteriorly expanded premaxilla, long premaxilla26 maxilla suture, broad premaxillary facet on the maxilla, closed otic notch, and small, striated, hooked teeth. The orbits are reduced relative to other 27 halisaurines while the snout is robust and flat with a broad, rounded tip. The jaws bear numerous small, hooked, snake-like teeth. Skulls imply 28 lengths of 5-6 meters; referred material suggests lengths of ≥10 meters. Pluridens’ specialized morphology – especially the contrasting large size 29 and small teeth - suggests a distinct feeding strategy. Small orbits imply that P. serpentis relied on nonvisual cues including touch and 30 chemoreception during foraging, as in modern marine snakes. Numerous neurovascular foramina on the premaxillae are consistent with this idea. The small teeth suggest proportionately small prey. The dentary becomes massive and robust in the largest individuals, suggesting sexual selection and perhaps sexual dimorphism, with the mandibles possibly functioning for combat as in modern beaked whales and lizards. The new mosasaur emphasizes how Maastrichtian mosasaurids were characterized by high species richness, functional diversity of niches occupied, and a certain degree of endemism, i.e. geographic specialization. and continued diversifying until the end of the Cretaceous, just prior to the K-Pg extinction.

Domaines

Paléontologie
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Dates et versions

hal-03370833 , version 1 (08-10-2021)

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Nicholas R Longrich, Nathalie Bardet, Fatima Khaldoune, Oussama Khadiri Yazami, Nour-Eddine Jalil. Pluridens serpentis, a new mosasaurid (Mosasauridae: Halisaurinae) from the Maastrichtian of Morocco and implications for mosasaur diversity. Cretaceous Research, In press, ⟨10.1016/j.cretres.2021.104882⟩. ⟨hal-03370833⟩
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