An appalachian species of the Silurian ostracode genus Craspedobolbina

Abstract

Beyrichia kirki Ulrich & Bassler 1923 and B. lakemontensis from the Mastigobolbina typus Zone (Upper Clinton Formation, late Llandoverian) in Pennsylvania are revised and redescribed as one species, Craspedobolbina kirki (Ulrich & Bassler 1923). This is the only species of Craspedobolbina from America described hitherto. Its sexual dimorphism is manifest not only in the formation of a crumina but also in a paracruminal inflation of the syllobium. Far-reaching reconstructive retouching of the figures accompanying the-original description has prevented earlier recognition of this species as a Craspedobolbina.