Lejopyge vs Tomagnostus

Lejopyge is an extinct genus of small, blind agnostid trilobites in the family Ptychagnostidae. Its species Lejopyge laevigata lived during the Guzhangian Stage of the Middle Cambrian and has a broad geographic distribution in marine strata. The first appearance of Lejopyge laevigata is used to define and correlate a major Cambrian interval, and the genus is used in international Cambrian biostrat...

Tomagnostus is a genus of agnostid trilobites known from Middle Cambrian marine rocks. Its members were small, blind arthropods with a two-part body plan in which the cephalon and pygidium were similar in size and shape. Fossils assigned to Tomagnostus occur across several paleocontinents, making the genus useful for correlating Cambrian strata and identifying particular intervals of geological ti...