ecofactbook
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species
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Animalia
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Arthropoda
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Trilobita
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Ptychopariida
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Norwoodiidae
/
Holcacephalus
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Holcacephalus appalachius
Holcacephalus glabrus
Holcacephalus granulatus
Holcacephalus praecursor
Holcacephalus robustus
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