Editing Redlichiida (section)

== Suborders ==
The order Redlichiida is divided into two [[suborder]]s: [[Olenellina]] and [[Redlichiina]]. The main difference between the two groups is the lack of facial sutures in the Olenellina. This absence of the facial sutures is regarded as primitive by most scholars. [[Trilobite#Dorsal sutures|Opisthoparian facial sutures]] are a shared character of all Redlichiina. In other trilobites, dorsal sutures may be opisthoparian, gonatoparian, proparian or they may be lost secondarily. The absence in the fossil record of the earliest larval stage, the protaspid, suggests that it may have been uncalcified, which would be a second unique character that distinguishes the Olenellina from all other trilobites.<ref name='Treatise'/>

Fossils of olenellinid trilobites are found in North America, and other associated areas that comprised the Cambrian continent of [[Laurentia]]. They are very common and are used to define the extent of Laurentia. Their abrupt disappearance marks the boundary between the Lower and the Middle Cambrian.

Fossils of redlichiinid are associated with Cambrian regions other than Laurentia.