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Technosaurus
''Technosaurus'' (meaning "(Texas) Tech lizard") is an extinct genus of Late Triassic archosauriform, from the Norian age Upper Triassic Bull Canyon Formation (Dockum Group) of Texas, United States.
For about 20 years after its description, it was thought to be a basal ornithischian dinosaur, but better remains of other Triassic archosaurs have cast doubt on this interpretation. As named, it was a chimera of different animals.
==Description and history==
''Technosaurus'' is based on TTUP P9021, which initially consisted of a premaxilla (tip of the upper jaw), two lower jaw pieces, a back vertebra, and an astragalus. ''Technosaurus'' and its type species, ''T. smalli'', were named by Sankar Chatterjee in 1984. He described it as a fabrosaurid, a clade of small early ornithischians now considered to have been an artificial grouping. Material from the quarry where P9021 was found is disassociated and comes from a variety of Late Triassic animals, which would prove problematic.
The genus was reviewed in 1991 by Paul Sereno, who interpreted the premaxilla and a fragment from the front of the lower jaw as pertaining to a hatchling prosauropod, and found the vertebra to be indeterminate and the astragalus an unidentifiable fragment. Thus, he restricted the remains to be considered ''Technosaurus'' to the second lower jaw piece, a posterior fragment.〔 It was further reviewed in the light of new remains that spurred reevalutation of purported Triassic dinosaurs, particularly ornithischians named from tooth or jaw material. Irmis ''et al.'' (2007) agreed with the removal of the vertebra and astragalus, but found no characteristics that were unambiguously dinosaurian in the skull fragments. They noted similarities to ''Silesaurus'' in the jaw fragments Sereno had excluded, and themselves excluded the posterior fragment as actually belonging to the unusual rauisuchian ''Shuvosaurus''.〔 These authors would later restate their case, concluding that ''Technosaurus'', defined only by the premaxilla and non-''Shuvosaurus'' lower jaw fragment, was a valid, diagnostic genus, but could not be definitely classified beyond Archosauriformes ''incertae sedis'', and was unlikely to be either an ornithischian or sauropodomorph dinosaur.
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
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