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''Ornithostoma'' (meaning "bird mouth") is a genus of pterodactyloid pterosaurs. In 1869, Harry Govier Seeley, cataloguing the fossils of the ''Sedgwick Museum'' at Cambridge, referred three snout fragments of toothless pterosaur specimens from the Lower Cretaceous Albian Cambridge Greensand of England to ''Ornithocheirus simus''.〔Seeley, H.G., 1869. ''Index to the Fossil Remains of Aves, Ornithosauria and Reptilia, from the Secondary System of Strata Arranged in the Woodwardian Museum of the University of Cambridge''. Cambridge, Deighton, Bell & Co〕 These fragments had in 1859 been described by Richard Owen and referred to ''Pterodactylus sedgwickii'' and ''Pterodactylus fittoni''.〔Owen R., 1859. ''Supplement (No. I) to the Monograph on the Fossil Reptilia of the Cretaceous Formations. Order Pterosauria Owen, genus ''Pterodactylus'' Cuvier''. Monographs of the Palaeontological Society of London, pp 1–19〕 By 1871 Seeley had realised ''Ornithocheirus simus'' was a toothed form, different from the fragments. Therefore he provisionally named them as a separate genus ''Ornithostoma'', the name derived from Greek ὄρνις, ''ornis'', "bird", and στόμα, ''stoma'', "mouth". Seeley as yet provided no specific name.〔Seeley, H.G., 1871, "Additional evidence of the structure of the head in Ornithosaurs from the Cambridge Upper Greensand; being a supplement to the "Ornithosauria"", ''Annals and Magazine of Natural History'' Series 4 7(37): 20-36〕 In 1891 however, he named the type species ''Ornithostoma sedgwicki'' Seeley 1891, apart from the snout fragments also referring to pelvis elements, claiming it was identical to ''Pteranodon'' and had priority. On that occasion he also selected a genolectotype from the three fragments, the holotype of the type species: specimen CAMSM B.54485.〔Seeley, H.G., 1891, "On the shoulder girdle in Cretaceous Ornithosauria", ''Annals and Magazine of Natural History'' Series 6 7: 237-255〕 Samuel Wendell Williston in 1893 independently also considered ''Ornithostoma'' a synonym of ''Pteranodon ingens''. He therefore renamed ''Pteranodon'' species: ''Ornithostoma ingens'' (Marsh 1872) Williston 1893 = ''Pteranodon ingens'' (= ''P. longiceps'') and ''Ornithostoma harpyia'' (Cope 1872) = ''P. longiceps''. Williston also created a special family and subfamily for ''Ornithostoma'': the Ornithostomatidae and the Ornithostomatinae. Today, these concepts are no longer used. Williston indicated ''O. ingens'' as the type species, not knowing one had already been designated.〔Williston, S.W., 1893, "Kansas pterodactyls, Part II", ''Kansas University Quarterly'', 2: 97-81〕 However, Richard Lydekker denied the identity in 1904 and, also unaware of Seeley's earlier species name, created a purported (third) type species ''O. seeleyi''.〔Lydekker R. 1904. "Vertebrate paleontology". In: J.E. Marr and A.E. Shipley (Eds.). ''Handbook to the Natural History of Cambridgeshire''. Cambridge, Cambridge University Press, pp 51–70〕 In 1914, Reginald Walter Hooley reviewed the material. He, incorrectly, claimed the pelvis elements were misidentified parts of the notarium of the shoulder girdel and referred several additional specimens to ''Ornithostoma'', among them a skull fragment featuring a crest base, specimen CAMSM B.54406, and postcranial fragments such as vertebrae and limbs.〔Hooley R.W., 1914, "On the ornithosaurian genus ''Ornithocheirus'', with a review of the specimens of the Cambridge Greensand in the Sedgwick Museum", ''Annals and Magazine of Natural History, Series 8'', 13: 529–557〕 In a 1994 paper, S. Christopher Bennett like Lydekker considered ''Ornithostoma'' to be distinct from ''Pteranodon'', mainly because of the lower edge ridges of the jaw. He also concluded that it was a ''nomen dubium''.〔Bennett, S.C., 1994, "Taxonomy and systematics of the Late Cretaceous pterosaur ''Pteranodon'' (Pterosauria, Pterodactyloidea)", ''Occasional Papers of the Natural History Museum Kansas'' 169: 1-70〕 This in 2001 was rejected however, by David Unwin who thought ''Ornithostoma'' to be a valid genus belonging to the Pteranodontidae, but limited the referable material to the original three fragments, including perhaps CAMSM B.54406. Hooley's postcranial fragments he referred to ''Lonchodectes''.〔Unwin D.M., 2001, "An overview of the pterosaur assemblage from the Cambridge Greensand (Cretaceous) of Eastern England", ''Mitteilungen aus dem Museum für Naturkunde in Berlin'', Geowissenschaftliche Reihe 4: 189–221〕 In 2012, Alexander O. Averianov again recombined the holotype with CAMSM B.54406 and selected postcrania, the combination showing traits that indicated a position in the Azhdarchoidea, representing an animal similar in some ways to ''Tapejara''.〔Averianov, A.O. (2012). "''Ornithostoma sedgwicki'' – valid taxon of azhdarchoid pterosaurs." ''Proceedings of the Zoological Institute RAS'', 316(1): 40–49.〕 The holotype specimen is a snout fragment with a length of about five centimetres or two inches. It represents a triangular cross-section of the snout, about an inch high. There is no crest and the jaws are toothless but featuring low protruding rims. The fragment is tapering towards the front, the upper edge inclining under an angle of 12°, indicating the snout tip was located about ten centimetres to the front of the breakage forming the anterior edge of the fragment.〔 There has also an ''Ornithostoma'' species been based on a find from Russia. In 1914 Nikolai Nikolaevich Bogolubov named a single large vertebra found near Pterovsk ''Ornithostoma orientalis''.〔Bogolubov, N.N., 1914, "O pozvonk’ pterodaktilya uz’ vyerkhnyem’lovyikh’ otlozhyenii Saratovskoi gubyernii", ''Ezhegodnik po Geologii i Mineralogii Rossii'', 16: 1–7〕 The name was emended to ''O. orientale'' by George Olshevsky in 1991 because ''stoma'' is neuter. It has been renamed ''Bogolubovia orientalis'' (Nesov & Yarkov 1989) and been transferred from the Pteranodontidae to the Azhdarchidae. ==See also== * List of pterosaurs 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「Ornithostoma」の詳細全文を読む スポンサード リンク
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