Agnostida

The trilobite Peronopsis interstrictus from the order Agnostida

• Worldwide

The Agnostida are recognized by a currently nine orders of the class of trilobites. They were small to very small trilobites from usually only a few millimeters in length, with a very similar form in the head shield ( cephalon ) and tail shield ( pygidium ), typically often curled.

The head shield is created almost circular in general and corresponds in size and shape often the tail plate, so you do not always looks right at first glance what you have right to the head or the tail. There are often no visible seams molting.

Occurrence

These small trilobites are typical of the Cambrian. But types of Agnostina occur to Upper Ordovician.

Submissions

This order has two suborders: Agnostina and Eodiscina. The Agnostina always have a two-tier chest and always no eyes. The Eodiscina usually have a tripartite thorax and usually no eyes.