New Elvinia Zone (Upper Cambrian) trilobites from new localities in the Collier Shale, Ouachita Mountains, Arkansas

Abstract

Three new species of trilobites, Erixanium lacunatum, Cernuolimbus monilis, and Anechocephalus aphelodermus, have been recovered from two new fossiliferous localities in the normally unfossiliferous Collier Shale in the Ouachita Mountains of west-central Arkansas. These new taxa occur with other trilobites previously reported from the Elvinia Zone in the Collier and elsewhere. Like the other trilobites reported from the Collier, these new taxa were originally deposited on the outer shelf, and were later eroded and redeposited in the adjacent, deep-water basin. Other species assigned to these genera have also been reported from outer shelf or continental slope sites. Species of Erixanium were widely distributed in equatorial and subtropical paleolatitudes in the Late Cambrian.