Olenellus is a genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of trilobite

Trilobite

Trilobites are a well-known fossil group of extinct marine arthropods that form the class Trilobita. The first appearance of trilobites in the fossil record defines the base of the Atdabanian stage of the Early Cambrian period , and they flourished throughout the lower Paleozoic era before...

 that lived during the Early Cambrian

Cambrian

The Cambrian is the first geological period of the Paleozoic Era, lasting from Mya ; it is succeeded by the Ordovician. Its subdivisions, and indeed its base, are somewhat in flux. The period was established by Adam Sedgwick, who named it after Cambria, the Latin name for Wales, where Britain's...

. It is commonly found in areas of Europe and North America (more specimens have been found in the upper Midwest and in Texas). When it was first described, Olenellus was thought to represent the earliest trilobite, although Holmia (= Esmeraldina) rowei and Nevadia

Nevadia

Nevadia is a genus of trilobites of the family Nevadiidae....

 weeksi have since been shown to pre-date Olenellus.

Olenellus is present in the Hardyston Quartzite

Hardyston Quartzite

The Cambrian Hardyston Formation or Hardyston Quartzite is a mapped bedrock unit in Pennsylvania and New Jersey.It was originally described by Wolff and Brooks in 1898, where two outcrops in Hardyston Township, Sussex County, New Jersey, were described...

 in New Jersey. It also may be found in the shale beds of the Kinzers Formation in Pennsylvania.

External links

• Trilobites Online (Olenellus crassimarginatus)