The Status of the Ordovician Trilobite Genera Prionocheilus and Polyeres

Prionocheilus and Polyeres are valid trilobite genera created in 1847 by M. Rouault, based on faunas in the Rennes district of France. Hawle and Corda, in the same year, set up the genera Pharostoma and Selenopeltis, which have been considered congeneric with the first-mentioned genera. It has recently been ascertained that Rouault9s paper was published in April 1847, thereby antedating Hawle and Corda by three months. Consequently, Prionocheilus and Polyeres have priority. The subfamily names remain as Pharostomatinae and Selenopeltinae.