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 Here is a trilobite of the species Cnemidopyge nuda nuda with the frontal spine as a detailed example. 
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| Location: | Minsterly, Shropshire, UK | ||
| Size of Trilobite: | about 34 mm long | ||
| Age: | Ordovician, Llanvirn Didymograptus artus-Biozone Hope Shale Formation (about 455 Mill. Years) | ||