The polyplacophoranMattheviaWalcott, 1885 has been reported previously only from Cambrian rocks. Recovery of specimens of two different species of Matthevia from the top of the cherty lower Gasconade Dolomite in Missouri extends the known range of the genus into the Ordovician. The presence of the Lower Ordovician trilobite PraepatokephalusLochman, 1964 in one collection provides the biostratigraphic evidence that the new specimens of Matthevia are Ordovician in age. Matthevia erecta n. sp. is described. An emended diagnosis for the trilobite Praepatokephalus is provided; two species of the genus are briefly described but are left in open nomenclature...

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