Olenellina

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Olenellina
Mesonacis vermontanus , a trilobite of the suborder Olenellina© Sam Gon III
Mesonacis vermontanus , a trilobite of the suborder Olenellina
© Sam Gon III
Conservation status
Extinct (fossil)
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Trilobita
Order: Redlichiida
Suborder: Olenellina
Superfamilies
  • Superfamily Olenelloidea
  • Superfamily Fallotaspidoidea
    • Archaeaspididae
    • Fallotaspididae
    • Judomiidae
    • Neltneriidae
    • Nevadiidae

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.

[edit] Physiology

(See the Trilobite article for a definition 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.


[edit] References