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 redlichiid trilobites died out before the end of the Middle Cambrian.