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Eumetazoa (metazoans)
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Bilateria (bilaterally symmetrical animals)
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Deuterostomia (deuterostomes)
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Echinodermata (sea stars, sea urchins, sea cucumbers, and relatives)
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Class Echinoidea
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Order Cassiduloida
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Family Apatopygidae
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Genus Apatopygus
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Genus Porterpygus
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