Asaphus lepidurus Basal Russian Lower Ordovician Trilobite

Description: A well-inflated example of an ancient member of the Asaphidae, this is Asaphus lepidurus. The region in which these trilobites lived was subject to dramatic changes in salinity and turbidity, and the trilobites were able to make rapid (geologically speaking) evolutionary adjustments. These adjustments were thought to be able to allow them to see both predator and prey more easily. This taxon was a basal trilobite, younger only than the founding Asaphus broggeri, that ultimately led to the dramatic radiation of the Asaphids in the region. Notice the distinctive terrace lines on the axial lobe, a distinguishing feature of the taxon. This large example also has a 37 mm by 25 mm on the same matrix plate, making for a nice association piece.