Olenellina
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 Mesonacis vermontanus , a trilobite of the suborder Olenellina
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Extinct (fossil)
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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
- Hagadorn, J.W. (2002). "Burgess Shale-type Localities: The global picture", in Bottjer, D.J., W. Etter, J.W. Hagadorn & C.M. Tang, eds: Exceptional Fossil Preservation -- A Unique View on the Evolution of Marine Life. Columbia University Press. ISBN 0231102542.
- Greg Edgecombe and the Australian Museum. Australian Trilobites: A Species List and Bibliography. Retrieved on August 23, 2005.
- Sam Gon III. A guide to the Orders of Trilobites. Retrieved on August 23, 2005.
- Nedin, C. (1995). "The Emu Bay Shale, a Lower Cambrian fossil Lagerstätte, Kangaroo Island, South Australia". Memoirs of the Association of Australasian Palaeontologists 18: 31-40.
- Simpson, Dave. Trilobites of South Australia. Retrieved on August 23, 2005.
