Detailed Free-Swimming Cretaceous Crinoid from Lebanon

Description: This is an exquisitely-preserved example of a free-swimming, stemless crinoid from the Cretaceous Sublithographic Limestone of Haqel, Lebanon, currently known as Antedon. The genus has been called Pterocoma , but that genus is preoccupied by a genus of insects established in 1834. The elongated pinnules seem to be an adaptation to a low current environment. The long pinnules would be better able to filter out the limited food supplies, giving this crinoid an advantage over others. The genus was quite long-lived in that it was found in the Jurassic deposits of Solnhofen, Germany. This one shows some evidence of post-mortem orientation by the current with most of the arms streaming off to the left.