Redlichiida is an order of trilobites, a group of extinct marine arthropods. Species assigned to the order Redlichiida are among the first trilobites to appear in the fossil record, about halfway during the Lower Cambrian. Due to the difficulty to relate sediments in different areas, there remains some discussion, but among the earliest are Fallotaspis (suborder Olenellina), and Lemdadella (suborder Redlichiina), both belonging to this order. However, the first representatives of the orders Corynexochida and Ptychopariida also appear very early on and may prove to be even earlier than any redlichiid species. However, in terms of anatomical comparison, the earliest redlichiid species are probably ancestral to all other trilobite orders and share many primitive characters. The last redlichii