Olenellidae
Olenellidae is an extinct family of redlichiid trilobite arthropods. Olenellids lived during the late Lower Cambrian in the Olenellus-zone in the former paleocontinent of Laurentia and parts of what became the Famatinian orogen in what is now Argentina. This family can be distinguished from most other Olenellina by the partial merger of the frontal and middle pair of lateral lobes of the central area of the cephalon, that is called glabella, creating two isolated slits.