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''Smok'' (meaning "dragon" in Polish) is an extinct genus of large carnivorous archosaur. It lived during the latest Triassic period (latest Norian to early Rhaetian stage, between 205–200 Ma). Its remains have been found in Lisowice, southern Poland. The type species is ''Smok wawelski'' (after the Wawel Dragon) and was named in 2011. It is larger than any other known predatory archosaur from the Late Triassic or Early Jurassic of central Europe. The relation of ''Smok'' to other archosaurs has not yet been thoroughly studied; it may be a rauisuchid, prestosuchid or ornithosuchid crurotarsan (part of the crocodile line of archosaurs) or a theropod dinosaur (part of the bird line of archosaurs). ==Description== At an estimated in length, ''Smok'' was the largest carnivorous archosaur in central Europe at the time. It was larger than any other known theropod dinosaur or pseudosuchian living in central Europe during either the Late Triassic or Early Jurassic. The skull is long.〔 Several features indicate that ''Smok'' is an archosaur, including serrated teeth, a contact between the jugal and quadratojugal bones at the back of the skull, a hole in front of the eye socket called the antorbital fenestra, maxillae bones in the upper jaw that connect along their palatal processes, and a rounded projection on the upper part of the femur bone.〔 The braincase of ''Smok'' includes many derived (advanced) features. The most prominent of these is a funnel-shaped structure on the bottom of the braincase, formed by a very wide, rounded basisphenoid bone. A deep notch called the basisphenoid recess cuts into the back of this funnel. Above the funnel is a very thin area of the braincase that is formed by deep depressions on the basisphenoids.〔 ''Smok'' has several features that are shared with both dinosaurs and crocodile-line archosaurs, making classification difficult. Similarities with theropods include a groove, or antitrochanter, on the ilium bone of the hip that is part of the acetabulum (a depression where the head of the femur attaches to the hip). ''Smok'' and theropods also have an anterior trochanter on the femur. Some large theropods share with ''Smok'' the deep depressions of the basisphenoids in the braincase. Similarities with rauisuchians include a triangular antorbital fenestra and a connection between the ectopterygoid and jugal bones of the skull that is split into two projections. The hip of ''Smok'' has a ridge on the lateral surface of the ilium above the acetabulum. This ridge is a defining characteristic of rauisuchians, forming a buttress over the femur and giving these animals a pillar-erect stance.〔 Other features of ''Smok'' seem to exclude it from these groups of archosaurs. The premaxilla and maxilla of the upper jaw attach closely to each other, making a continuous row of evenly spaced teeth. Early theropods and orthithosuchids have a toothless gap between the premaxilla and the maxilla, distinguishing them from ''Smok''. The upper jaw bones of rauisuchians are not closely connected, leaving a small opening between the premaxilla and maxilla that is not seen in ''Smok''. Unlike many pseudosuchids and theropods, ''Smok'' does not have pneumatic areas, or air pockets, in the braincase. It also has several features that link it with primitive archosauromorphs, including the presence of a postfrontal bone on the skull and a closed acetabulum in the hip.〔 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「Smok (archosaur)」の詳細全文を読む スポンサード リンク
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