Atops vs Eurekia

Atops is an extinct genus of trilobites, a group of marine arthropods that lived during the early Cambrian Period. The genus is associated with the late Atdabanian stage, an interval commonly placed in the early part of the Cambrian and dated to roughly 530 to 524 million years ago. Atops is therefore relevant to studies of early trilobite diversification and Cambrian marine fossil assemblages.

Eurekia is an extinct genus of asaphid trilobites placed in the family Eurekiidae. It is known from Late Cambrian and earliest Ordovician marine rocks of Laurentian North America, including the House Range of Utah, Nevada, and the Upper Mississippi Valley. The genus includes species such as Eurekia angustifrons and Eurekia apopsis, and its occurrences help document the transition from Cambrian to...