| 翻訳と辞書 |
Lucasuchus
''Lucasuchus'' is an extinct genus of aetosaur. Fossils have been found from the Bull Canyon Formation of the Dockum Group outcropping in the Revuelto Creek locality in Quay County, New Mexico. All specimens date back to the Norian stage of the Late Triassic. The genus was named in 1995 after the American paleontologist Spencer G. Lucas.〔Long, R. A., and Murry, P. A. (1995). Late Triassic (Carnian and Norian) tetrapods from the southwestern United States. ''New Mexico Museum of Natural History and Science Bulletin 4'', 254 pp.〕
''Lucasuchus'' was first proposed to be a junior subjective synonym of ''Longosuchus'' in 1999, and several other studies have also considered it to be an invalid genus.〔A new aetosaur (Reptilia: Archosauria) from the Upper Triassic of Texas and the phylogeny of aetosaurs. ''Journal of Vertebrate Paleontology'' 19(1):50-68.〕〔Heckert, A. B., Lucas, S. G., Hunt, A. P., and Spielmann, J. A. (2007). Late Triassic aetosaur biochronology revised. ''In:'' Lucas, S. G. and Spielmann, J. A., eds., ''The Global Triassic''. New Mexico Museum of Natural History and Science Bulletin 41.〕 However, more recent studies concluded that ''Lucasuchus'' is not congeneric with any other known aetosaur genus, and is likely to be more closely related to ''Desmatosuchus'' and ''Acaenasuchus'' than to ''Longosuchus''.〔Harris, S. R., Gower, D. J., and Wilkinson, M. (2003). Intraorganismal homology, character construction, and the phylogeny of aetosaurian archosaurs (Reptilia, Diapsida). ''Systematic Biology'' 52(2):239-252.〕 The presence of elongate lateral osteoderm horns is shared by all of these genera, which make up the subfamily Desmatosuchinae.〔Martz, J. W. and Small, B. J. (2006). ''Tecovasuchus chatterjeei'', a new aetosaur (Archosauria: Stagonolepididae) from the Tecovas Formation (Carnian, Upper Triassic) of Texas. ''Journal of Vertebrate Paleontology'' 26(2):308–320.〕〔Huene, F. V. (1942). Lieferungen 3/4. Pseudosuchia, Saurischia, Rhynchosauridae und Schlussabschnitt. ''Die Fossilen Reptilien des Südamerikanischen Gondwanalandes. Ergebnisse der Sauriergrabungen in Südbrasilien 1928/29. C. H. Beck'sche Verlagsbuchhandlung, München'' 161-332.〕〔Heckert, A. B. and Lucas, S. G. (2000). Taxonomy, phylogeny, biostratigraphy, biochronology, paleobiogeography, and evolution of the Late Triassic Aetosauria (Archosauria: Crurotarsi). ''Zentralblatt für Geologie und Paläontologie Teil I'' 1998:1539–1587.〕〔Sereno, P. C. (2005). (Desmatosuchinae ). Stem Archosauria ''TaxonSearch (1.0, 2005 November 7 )''. Retrieved on 2009-07-18.〕
It has been suggested that ''Lucasuchus'' is either a sexual dimorph belonging to the same species as ''Longosuchus meadei'' or an ontogenetic stage of the species (meaning that it represents one particular age group). However, several characteristics of ''Lucasuchus'' may indicate that it is indeed distinct from ''L. meadei'' rather than an example of morphological variation. For example, ''Lucasuchus'' has a clear radial pattern of pits and grooves on the paramedian osteoderms of the back while ''Longosuchus'' has only a random pattern of pits on the paramedians. In ''Lucasuchus'', the paramedians have large conical eminences, or projections, while in ''Longosuchus'' these projections are only present in the form of low pyramidal bosses. ''Lucasuchus'' also lacks the emarginations (or notches) on the spikes of the lateral osteoderms that are seen in ''Longosuchus''.
==References==
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「Lucasuchus」の詳細全文を読む
スポンサード リンク
| 翻訳と辞書 : 翻訳のためのインターネットリソース |
Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.
|
|