|
''Avisaurus'' (meaning "bird lizard") is a genus of enantiornithine bird from the Late Cretaceous of North America.〔(PaleoBiology Database: ''Avisaurus'', basic info )〕 Two species are known; the type species ''A. archibaldi'' and ''A. gloriae''.〔Varrichio, David J., Chiappe, Luis M. (1995) "A New Enantiornithine Bird From the Upper Cretaceous Two medicine Formation of Montana" " Journal of Vertebrate Paleontology" March 14, 1995, Vol. 15, no. 1, pp. 201 - 204〕 Both are known only from single fossilized bones of the foot — the tarsometatarsus. Both species of ''Avisaurus'' are known from the humid low-lying swamps, lakes, and river basins of the western shore of the Western Interior Seaway, and from the much more arid uplands between that area and the Cordilleran Overthrust Belt which eventually formed the Rocky Mountains. This genus belongs to the enantiornithine family Avisauridae, which also contains similar animals from South America such as ''Soroavisaurus'' 〔Chiappe, Luis M. (1993) " Enantiornithine (Aves) Tarsometatarsi from the Cretaceous Lecho Formation of Northwestern Argentina" ''American Museum Novitates'' December 27, 1993 Number 3083 pp. 1-2〕 and ''Neuquenornis'' 〔Chiappe, Luis M., Calvo, Jorge O. (1994) "Neuquenornis volans, a New Late Cretaceous Bird (Enantiornithes: Avisauridae) from Patagonia, Argentina" "Journal of Vertebrate Paleontology" June 22, 1994 Volume 14 No. 2 pp.230-246.〕 In the Late Cretaceous the Americas were still separated by a branch of the Tethys Ocean. The presence of reported ''Avisaurus'' remains in both North and South America has been put forward as evidence that faunal changes in the southern half of North America during the Lancian resulted from an immigration event of South American taxa moving north.〔Lehman, T. M., 2001, Late Cretaceous dinosaur provinciality: In: Mesozoic Vertebrate Life, edited by Tanke, D. H., and Carpenter, K., Indiana University Press, pp. 310-328.〕 ==''Avisaurus archibaldi''== ''A. archibaldi'' was discovered in the Late Cretaceous Hell Creek Formation of North America (Maastrichtian, from c.70.6-66 million years ago), making it one of the last enantiornithids. It was collected in 1975 in the UCMP locality V73097, in Garfield County, Montana, USA. ''A. archibaldi'' is represented by a single fossil of a tarsometatarsus in the collection of the University of California Museum of Paleontology. It has the catalog number UCMP 117600. It was initially described as the left tarsometatarsus of a non-avian theropod by Brett-Surman and Paul in 1985. It was later redescribed as the right tarsometatarsus of an enantiornithine bird by Chiappe in 1992.〔Chiappe, Luis M. (1992) "Enantiornithine (Aves) Tarsometatarsi and the Avian Affinities of the Late Cretaceous Avisauridae" "Journal of Vertebrate Paleontology" September 3, 1992, Volume 12 no. 3 pp. 344-350〕 The specimen has a maximum length of 73.9 mm, making it one of the largest known tarsometatarsi of an enantiornithine.〔 It is named after J. David Archibald, its discoverer, from The University of California, Berkeley. 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「Avisaurus」の詳細全文を読む スポンサード リンク
|