Olenellina

Olenellina is a suborder of the order Redlichiida of Trilobites. The suborder contains two superfamilies: Olenelloidea (with 2 families), and Fallotaspidoidea (with 5 families). The Olenillina are some of the most primitive trilobites. They originated at the beginning of the Cambrian era and became extinct at the end of the lower Cambrian.

Physiology

(See Trilobite: Terminology for definitions of morphological terms)

Cephalon: Lacking facial sutures and the glabella typically has rather deep lateral furrows. In some species the front glabellar lobe is an almost circular boss. There is a conterminant hypostome with a very wide rostral plate extending between genal angles, with a perrostral suture (no connective sutures).

Thorax: Numerous segments, is non-fulcrate with the axis often spine-bearing.

Pygidium: Narrow, with few segments.

Olenellina are the earliest trilobites in Cambrian stratigraphy. No calcified protaspis is known, the body is flattened and the cuticle is thin.

References