Crinoid

Clematocrinus retiarius

• Silurian
• Much Wenlock Limestone Formation
• Wren's Nest, Dudley, England, UK

Size: 1.5 cm crown

A classic Dudley crinoid, Clematocrinus retiarius is a very small species with a crown size under 2 cm, and I believe the most common crinoid of the Wenlock Limestone. Its most notable feature is its remarkably long, tendril-like cirri distributed in clusters along the length of the stem. Crinoid cirri are mobile(!) appendages that help anchor the animal in place. While they are hardly unique to this species, they are absent in many Paleozoic crinoids and rarely as proportionately long as in C. retiarius.