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Suborder:
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Tornoceratina 
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Superfamily:
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Tornoceratoidea 
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Family:
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Tornoceratidae 
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Subfamily:
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Tornoceratinae 
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| 
Genus:
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Crassotornoceras? 
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Species:
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isolatum | 
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Qualifier:
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ss | 
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Author:
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	Becker 1993,p.186	 
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Lower Boundary:
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UD2A--UD2B:(verneuili Zone base) [07,75], 374 million years
 
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| 
Upper Boundary:
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UD2F--UD2G:(subvaricatum Zone base), 370.8 million years
 
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