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Eumetazoa (metazoans)- 
    
Bilateria (bilaterally symmetrical animals)- 
    
Protostomia (protostomes)- 
    
    
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Tardigrada (water bears)- 
    
Class Heterotardigrada- 
    
Order Arthrotardigrada- 
    
Family Halechiniscidae- 
    
Genus Actinarctus- 
        
Species Actinarctus doryphorus
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Species Actinarctus lyrophorus
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Species Actinarctus neretinus
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Species Actinarctus physophorus
 
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