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Suborder:
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Goniatitina 
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Superfamily:
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Dimorphoceratoidea 
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Family:
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Girtyoceratidae 
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Subfamily:
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Girtyoceratinae 
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Genus:
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Girtyoceras 
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Species:
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gordoni | 
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Qualifier:
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ss | 
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Author:
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	Korn, D & Titus, A 2011, p. 146	 
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Lower Boundary:
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DER Go alpha 2--Go alpha 3  [11.60], 332.3 million years
 
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| 
Upper Boundary:
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DER fimbriatus--spirifer/striatus, 330.7 million years
 
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