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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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Posttornoceratidae 
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Genus:
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Exotornoceras | 
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Qualifier:
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ge | 
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Author:
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	Becker 1984, p.64	 
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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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P.delph.--low.Platyclym.annulata IIIb/IV, 367.6 million years
 
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