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''Lonchodomas'' is a genus of trilobites, that lived during the Ordovician. It was eyeless, like all raphiophorids, and had a long straight sword-like frontal spine, that gradually transforms into the relatively long glabella. Both the glabellar spine and the backward directed genal spines are subquadrate in section. ''Lonchodomas'' has five thorax segments and the pleural area of the pygidium has two narrow furrows. ''Lonchodomas'' occurred in what are today Argentina, Canada (Newfoundland), Estonia, Latvia, Norway, the Russian Federation (St. Petersburg region) and the United States (Oklahoma, Virginia). == Distribution == * ''L. carinatus'' is found in the Upper Ordovician of the United States (Lower Member and Botetourt limestone Member, of the Edinburg Formation, Shenandoah County, Virginia, 39.0° N, 78.4° W Blackriveran 460.9 - 449.5 Ma)〔 cited in (【引用サイトリンク】website= Paleobiology Database )〕 * ''L. clavulus'' is present in the Middle Ordovician of Newfoundland, Canada (''Histiodella kristinae'' conodont zone, Table Cove Formation; Table Point, "Middle Table Head" and Table Cove).〔 cited in (【引用サイトリンク】website= Paleobiology Database )〕 * ''L. mcgeheei'' is present in the Upper Ordovician of Oklahoma, United States (Bromide Formation, Sandbian). * ''L. retrolatus'' was collected from the Ordovician of Nevada (Eureka Quartzite, sandy limestone, 60–90 ft above base, Ranger Mountains, Nevada Test Site)) * ''L. rostratus'' is known from the Upper Ordovician of Estonia (Narva open pit, and Lasnamägi, Kukruse Stage, Sandbian) and Latvia (Remte 3 borehole, and Adze 6 borehole, Kukruse Stage, Sandbian). * ''L. suriensis'' was excavated from the Middle Ordovician of Argentina (Portillo del Cajón, Cerro Morado; Cerro Suri; Puesto El Despacho; Las Pircas; all La Rioja)〔 cited in 〕 * ''L. volborthi'' occurs in the Lower Ordovician of the Russian Federation (Volkhovian level, Putilovo quarry, St.Petersburg region). 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「Lonchodomas」の詳細全文を読む スポンサード リンク
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