Odontopleurida

Odontopleurida is an order of very spinose trilobites closely related to the trilobites of the order Lichida. Some experts group the Odontopleurid families, Odontopleuridae and Damesellidae, within Lichida. Odontopleurids tend to have convex, bar-shaped cephalons, and lobed, knob-shaped glabella that extend to, or almost to the anterior margin. Many, if not almost all odontopleurids have long spines that are derived either from the margins of the exoskeleton, or from granular or tubercular ornamentation, or both. Many odontopleurids are so spinose so as to be described as having "spines on (th