Crinoid

Clathrocrinus clathratus

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

Size: 3.5 cm crown

This is surely one of the most bizzare and beautiful crinoids within the Pontiac fauna. The brachials of "C. clathratus" are extraordinarily elongated and articulate with each other at nearly 90-degree angles. As a result, the arms form prominent zig-zag patterns which overall give the crown a cage-like (or "trellis"-like, as Strimple described) appearance. Evidently one of the more extreme approaches taken by the rising cladids in pursuing various filter-feeding niches.