Crinoid

Pterotocrinus depressus

• Mississippian
• Bangor Formation
• Franklin County, Alabama, USA

Size: 3 cm across the tegmen "wing" plates

Pterotocrinus is a very unusual crinoid aptly named for the striking "wings" arising from the tegmen ("Ptero-" deriving from the Greek word for "wing"). Different species of Pterotocrinus are often distinguished and named by the shape of these wings.