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''Masiakasaurus'' is a genus of small predatory theropod dinosaurs from the Late Cretaceous of Madagascar. In Malagasy, ''masiaka'' means "vicious"; thus, the genus name means "vicious lizard". The type species, ''Masiakasaurus knopfleri'', was named after the musician Mark Knopfler, whose music inspired the expedition crew. It was named in 2001 by Scott D. Sampson, Matthew Carrano, and Catherine A. Forster. Unlike most theropods, the front teeth of ''M. knopfleri'' projected forward instead of straight down. This unique dentition suggests that they had a specialized diet, perhaps including fish and other small prey. Other bones of the skeleton indicate that ''Masiakasaurus'' were bipedal, with much shorter forelimbs than hindlimbs. ''M. knopfleri'' reached an estimated adult body length of around 2 meters (about 6–7 feet). ''Masiakasaurus'' lived around 70 million years ago, along with animals such as ''Majungasaurus'', ''Rapetosaurus'', and ''Rahonavis''. ''Masiakasaurus'' was a member of the group Noasauridae, small predatory ceratosaurs found primarily in South America. ==Description== ''Masiakasaurus'' were small-bodied ceratosaurs that grew up to around in length. The most distinctive characteristic of ''Masiakasaurus'' is the forward-projecting, or procumbent, front teeth. The teeth are heterodont, meaning that they have different shapes along the jaw. The first four dentary teeth of the lower jaw project forward, with the first tooth angled only 10° from horizontal. These teeth are long and spoon-shaped with hooked edges. They have carinae, or sharp edges, that are weakly serrated. Serrations are more evident in the posterior teeth, which are also recurved and laterally compressed. The margin of the dentary curves downward so that the tooth sockets of the front teeth are directed forward. The front teeth of the upper jaw are also procumbent, and the margin of the premaxilla curves slightly upward to direct them outward. Unlike the skulls of abelisaurids, which are very deep, the skull of ''Masiakasaurus'' is long and low. The lacrimal and postorbital bones around the eye are textured with bumpy projections. Not including the highly modified jaws and teeth, the skull of ''Masiakasaurus'' possesses many general ceratosaurian characteristics. Overall, its morphology is intermediate between abelisaurids and more basal ceratosaurs.〔 The neck is relatively narrow in comparison to abelisaurids and bear stout neck ribs. While many theropods have s-shaped necks, the ribs would make the neck rather stiff in ''Masiakasaurus'', and the back of the neck is positioned almost horizontally, giving it only a slighter curve. Like those of other abelisauroids, the vertebrae are heavily pneumaticized, or hollowed, and have relatively short neural spines. Pneumaticity is limited to the neck and foremost back vertebrae, however. Pneumatic cavities are also present in the braincase.〔 The scapulocoracoid, a bone that makes up the pectoral girdle, is large and broad. While abelisaurids have arms that are extremely reduced in size, ''Masiakasaurus'' and other noasaurids had longer forelimbs. The humerus is slender and the bones of the hand are relatively short. The related genus ''Noasaurus'' has a raptorial ungual which was originally interpreted as a sickle-like claw on the foot, but has more recently been considered a claw of the hand. The penultimate phalanx, a finger bone that immediately precedes the raptorial ungual in ''Noasaurus'', is also known in ''Masiakasaurus'' and has a similar appearance. The enlarged ungual, however, is unknown in ''Masiakasaurus''.〔 The hand bore three large fingers with stout - but not particularly sharp - claws, and a highly reduced fourth finger. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Masiakasaurus」の詳細全文を読む スポンサード リンク
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