Mosasaurus (Halisaurus arambourgi) Skeleton, about... Lot 31

Mosasaurus (Halisaurus arambourgi) Skeleton, about 70 million years old, Morocco Fossil 267x111x22 cm Provenance: market (Italy) Conservation status. Surface area: 50%. Conservation status. Support: 50-60% (see restoration scheme; matrix reproduced with original sediment amalgam) The large family of mosasaurs-whose name means "Meuse River lizard"-collects an extinct group of scaly aquatic reptiles that lived, broadly speaking, between 82 and 66 million years ago during the Campanian and Maastrichtian phases of the late Cretaceous. The first mosasaur fossils were found as skulls in a chalk quarry near the Dutch city of Maastricht in the latexVIII century and were initially thought to be crocodiles or whales. A skull discovered around 1780 was nicknamed the "great animal of Maastricht," and had a very wide scientific resonance. In 1808, naturalist Georges Cuvier concluded that it belonged to a giant marine lizard with similarities to present-day lizards but otherwise different from any known living animal. This concept was revolutionary at the time and helped support the then developing ideas of extinction and evolution. William Daniel Conybeare in 1822 invented the name "mosasaurus" in reference to its origin in fossil deposits near the Meuse River. The scaly skin of mosasaurs keeps alive, among scholars, the controversy over whether the group should be more closely related to lizards or snakes. The fossil under consideration comes from the Ouled Abdoun Basin in Morocco and belongs to the genus Halisaurus, one of the key forms in the evolution of the mosasaur, identified by U.S. paleontologist Othniel Charles (1831-1899), in 1869 (who changed the name to Baptosaurus in 1870 to avoid confusion with Halosaurus, a prehistoric fish). The name is a cast from ancient Greek and means "sea lizard" (ἅλς + σαῦρος). Fossil deposits are known worldwide, with particularly complete remains found in Morocco and the United States. At 3-4 meters long, the alisaur was relatively small by mosasaur standards. In the classification of alisaurs, of particular importance is the discovery of a new type, made known only in 2005, by the working group of Nathalie Bardet and intotected to the French paleontologist Camille Arambourg (1885-1969), who is credited with extensive research in North Africa. To it belongs our specimen of Halisaurus arambourgi, whose name means "Arambourg's ocean lizard," in honor of the discovery of the large prehistoric basin identified by the scholar. Halosaurus arambourgi is from the Late Maastrichtian period, thus dating between 72.1 and 66 million years ago. It is a type that is well recognizable by the shape of its external nostrils (V-shaped anteriorly and U-shaped posteriorly), the shape of the quadratum (a part of the skull that has an oval vertical stapedial incisura), and the presence of anterior ridges on the frontal side. Its pterygoid bone also retains twelve teeth (three more than Halisaurus platyspondylus, its closest "cousin").