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''Avaceratops'' is a genus of small herbivorous ceratopsian dinosaurs which lived during the late Campanian during the Late Cretaceous Period in what are now the Northwest United States. ==Discoveries and species== The first remains of ''Avaceratops'' were found by fossil dealer Eddie Cole in the Judith River Formation of Montana, in 1981, on land of the Careless Creek Ranch, owned by rancher Arthur J. Lammers.〔"Avaceratops." In: Dodson, Peter & Britt, Brooks & Carpenter, Kenneth & Forster, Catherine A. & Gillette, David D. & Norell, Mark A. & Olshevsky, George & Parrish, J. Michael & Weishampel, David B. ''The Age of Dinosaurs''. Publications International, LTD. p. 129. ISBN 0-7853-0443-6.〕 They were preserved scattered throughout the remains of a prehistoric stream bed.〔 This ''Avaceratops'' specimen was likely buried in the sandbar after its body was swept downstream by the current.〔 The finds, displayed in Cole's fossil shop, were in October 1981 inspected by Peter Dodson who in July 1982 during a visit with Cole to the site discovered additional bones, which from 1984 were excavated by Anthony Fiorillo. The fossil was formally named and described by Dodson in 1986, as the type species ''Avaceratops lammersi''. It was the first ceratopsid named since ''Pachyrhinosaurus'' in 1950.〔 The genus was named after Ava Cole, Eddie's wife.〔 The specific epithet honors the Lammers family.〔 In 1990 George Olshevsky emended the name to ''A. lammersorum'', with the specific name in the genitive plural because it referred to several persons.〔Olshevsky, G., 1991, ''A revision of the parainfraclass Archosauria Cope, 1869, excluding the advanced Crocodylia. Mesozoic Meanderings 2'' 196 pp〕 However, Dodson objected against this change, arguing the genitive singular might also refer to a single family name.〔 The holotype, ANSP 15800, consists of a partial skeleton containing the lower skull, a left lower jaw, vertebrae, a complete shoulder girdle and most elements of forelimbs and hindlimbs. The type specimen might represent a juvenile or a subadult individual, Dodson in 1986 being inclined to consider it almost fully grown.〔 Kenneth Carpenter made a reconstruction of the skull, a cast of which was by Leroy Glenn combined with restored parts of the postcranial skeleton to create a mount that in 1986 was displayed in the Academy of Natural Sciences in Philadelphia; a copy of this skeletal mount was donated to the Upper Musselshell Valley Historical Museum in Harlowton.〔 In 1993 Paul Penkalski referred two earlier found squamosals to ''Avaceratops'', USNM 4802 and USNM 2415, of larger individuals.〔Penkalski, P.G., 1993, "The morphology of ''Avaceratops lammersi'', a primitive ceratopsid from the Campanian of Montana". ''Journal of Vertebrate Paleontology'' 13(3, suppl.): 52A〕 In 1999 Penkalski and Dodson described a second skull, MOR 692, again of a larger individual. This specimen includes the upper skull, with the nose and brow horns. In 1990 Thomas Lehman renamed ''A. lammersi'' into ''Monoclonius lammersi'';〔Lehman, T.M., 1990, "The ceratopsian subfamily Chasmosaurinae: sexual dimorphism and systematics". In: K. Carpenter and P. J. Currie (eds.), ''Dinosaur Systematics: Perspectives and Approaches'', Cambridge University Press, Cambridge pp 211-229〕 in 2010 the species was by Gregory S. Paul renamed into ''Centrosaurus lammersi''.〔Paul, G.S., 2010, ''The Princeton Field Guide to Dinosaurs'', Princeton University Press p. 264〕 Both alternative names have found no acceptance. 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「Avaceratops」の詳細全文を読む スポンサード リンク
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