Augustasaurus is a genus of aquatic sauropterygian reptile belonging to the Pistosauria, a clade containing plesiosaurs and their close relatives. Pistosaurus and Augustasaurus were thought to be the only known members of the family Pistosauridae. However, some recent cladistic analyses found Augustasaurus to be a more advanced pistosaur, as a sister group of the order Plesiosauria. The only known species of Augustasaurus is Augustasaurus hagdorni , which was first described in 1997.

 The first part of Augustasaurus' name comes from the Augusta Mountains of northwestern Nevada, where its fossil bones were first discovered. The second part of the name is the Greek word sauros (σαυρος), which means "lizard" or "reptile." The type species, Augustasaurus hagdorni, was named in honor of the paleontologist Hans Hagdorn.

 Augustasaurus' skull shares many general characteristics with its relative, Pistosaurus, such as tall, blade-like upper temporal arches. The skull's elongated rostrum tapers to a dull point, the anterior premaxillary and maxillary teeth have been described as "fang-like", and the squamosal makes a box-like suspensorium.

 The dorsal neural spines of Augustasaurus are low with rugose tops. Its coracoids are large plates similar to those in other plesiosaurs. However, the coracoid foramen are missing from Agustasaurus, in a way similar to those in the plesiosaur Corosaurus. Its cervical ribs have anterior process, and like most plesiosaurs, Augustasaurus' vertebrae have "thickened transverse processes".

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Tags: Вымершие рептилии, Триас, диапсиды, завроптеригии, лепидозавроморфы, пистозавры

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 Pistosaurus longaevus is an extinct genus of aquatic sauropterygian reptile closely related to plesiosaurs. Fossils have been found in France and Germany, and date to the Middle Triassic.

 Pistosaurus was about 3 metres (10 ft) long, and had a body form resembling that of nothosaurs, aquatic reptiles that flourished during the Triassic. However, the vertebral column was stiff, like that of a plesiosaur, implying that the animal used its paddle-like flippers to propel itself through the water, as the plesiosaurs probably did. The head also resembled that of a plesiosaur, but with the primitive palate of a nothosaur, and numerous, sharp teeth ideal for catching and eating fish.

Although it is unlikely that Pistosaurus was a direct ancestor of the plesiosaurs, the mixture of features suggests that it was closely related to that group.

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Tags: Вымершие рептилии, Триас, диапсиды, завроптеригии, лепидозавроморфы, пистозавры

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