Crinoid

Euonychocrinus simplex

• Pennsylvanian
• LaSalle Limestone Member, Bond Formation
• Charleston, Illinois, USA

Size: 2.7 cm crown

This crinoid is one of two unusual Flexible species found in the LaSalle crinoid fauna and closely-related to the familiar Mississippian flexibles such as Taxocrinus, in that the presence of a distinct anal tube arising from the CD interarray clearly assigns it to the Taxocrinoidea. Its most interesting feature is the secondary ramules given off by the tertibrachials, which form a biendotomous branching pattern in the upper-half of the crown (Strimple & Moore 1971).