Crinoid

Brabeocrinus christinae

• Pennsylvanian
• LaSalle Limestone, Bond Formation
• Pontiac/Ocoya, Illinois, USA

Size: 4 cm crown

This is one of the most common crinoids seen from the LaSalle Limestone-Bond Formation of Pontiac, Illinois. It displays the typical and more "primitive" cladid characteristics, including uniserial arms that bear pinnules. The level of preservation for this specimen, and for Pontiac crinoids in general, is exceptional by Pennsylvanian crinoid standards, as the majority of Pennsylvanian crinoids are found as lone calyxes, if even that. In fact, there are just a handful of localities in the world that produce articulated Pennsylvanian crowns with any regularity. The LaSalle Limestone is arguably the most important of them, both because its crinoids are of unparelleled quality and diversity, and because historically this locality enabled the first study of Pennsylvanian crinoids done principally on articulated crowns instead of calyxes.