Thalassotitan atrox (Largest known mosasaur species) Partial Dentary (Jaw) - Late Cretaceous - Fossil tooth (No reserve price)

Scientific name: †Thalassotitan atrox (Longrich et al., 2022) Old named as Prognathodon - Partial dentary with 2 Teeth + 1 germ emerging replacement tooth.

Location: Oued Zem, Morocco

Geological Formation: Ouled Abdoun Basin (Phosphate beds)

Age: Upper Cretaceous, Maastrichtian stage, (~66 Million Years)

Size: 12,5cm long

Ref: S352

Observations: This enormous Thalassotitan atrox its one of the largest known mosasaur species ( old named as Prognathodon sp). This is a fragment of the dentary (jaw) of this mosasaur species. It preserves 2 teeth + 1 germ emerging replacement tooth.

Regarding restorations and repairs: During excavation, the specimen suffered several fractures, including the teeth, which fell apart and had to be reattached to the jaw using the filling method. Even so, it is a magnificent, authentic example of the dentition of this huge mosasaur species.

Another very interesting aspect of this specimen is that a germ-emerging replacement tooth is visible within one dentary alveoli . Mosasaurs, like sharks or terrestrial dinosaurs, continuously replace their teeth throughout their lives. When a tooth begins to wear down, a new one starts to grow underneath and replaces it. Here is a magnificent example.

Diagnosis: Large mosasaurid, Premaxilla tip short and blunt. Interlocking contacts between premaxilla and maxilla. Maxilla deep, ventral margin convex. Interdigitating joint between maxilla and prefrontal formed by a series of tongue-and-groove joints, with margins of the joint interdigitating. Prefrontal broadly overlaps onto frontal. Prefrontal-postorbitofrontal excluding frontal from orbital margin. Frontal short, broad, strongly constricted anteriorly and strongly concave at contact with parietal anterolateral wings; postorbital processes displaced anteriorly; large posteromedial processes wrapping around parietal foramen. Jugal broad and robust where its contacts the maxilla. Quadrate massive with large, fused supra- and infrastapedial processes below median part of the shaft. Tooth crowns with anastomosed ornamentation of apex and serrated anterior and posterior carinae.

Its the most common specie in moroccan phosphates.

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