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[[Image:Trilobites.jpg|right|thumb|200px|A variety of Trilobites]]'''Trilobites''' are an extinct form of [[arthropod]]. They came in a wide variety of sizes ranging from being under a millimeter long to being over two feet in length.

[[Image:Trilobites.jpg|right|thumb|200px|A variety of Trilobites]]'''Trilobites''' are an extinct form of [[arthropod]]. They came in a wide variety of sizes ranging from being under a millimeter long to being over two feet in length.

==Evolution and extinction==

==Evolution and extinction==

Trilobites first appeared some 600  [[mega year ago|Ma]]. during the Cambrian period. They diversified into many orders, and over a (relatively) short time scale disappeared completly about 250 Ma.<ref>http://www.trilobites.info/trends.htm</ref> The causes of the extinction are not fully clear.<ref>http://www.trilobites.info/lasttrilos.htm</ref>

Trilobites first appeared some 600  [[mega year ago|Ma]]. during the Cambrian period. They diversified into many orders, and over a (relatively) short time scale disappeared completely about 250 Ma.<ref>http://www.trilobites.info/trends.htm</ref> The causes of the extinction are not fully clear.<ref>http://www.trilobites.info/lasttrilos.htm</ref>

==Morphology==  

==Morphology==