File:Ectenocrinus simplex (fossil crinoid) (Kope Formation, Upper Ordovician; northern Kentucky, USA).jpg

English: Ectenocrinus simplex (Hall, 1847) - fossil crinoid from the Ordovician of Indiana, USA.

This fossil is from the famous Cincinnatian Series of the tristate area of Ohio-Kentucky-Indiana. Rocks in the Cincinnatian were deposited in relatively shallow marine facies during the Late Ordovician. The Cincinnatian succession is mostly interbedded limestones and shales. Most of the limestones are event beds (= tempestites), deposited during ancient storms.

Crinoids (sea lilies) are sessile, benthic, filter-feeding, stalked echinoderms that are relatively common in the marine fossil record. Crinoids are also a living group, but are relatively uncommon in modern oceans. A crinoid is essentially a starfish-on-a-stick. The stick, or stem, is composed of numerous stacked columnals, like small poker chips. Stems and individual columnals are the most commonly encountered crinoid fossils in the field. Intact, fossilized crinoid heads (crowns, calices, cups) are unusual. Why? Upon death, the crinoid body starts disintegrating very rapidly. The soft tissues holding the skeletal pieces together decay and the skeleton falls apart.

Classification: Animalia, Echinodermata, Crinoidea, Disparida, Homocrinidaee

Stratigraphy: Kope Formation, Edenian Stage, lower Cincinnatian Series, Upper Ordovician

Locality: unrecorded/undisclosed site in northern Kentucky, USA

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See info. at:

en.wikipedia.org/wiki/Crinoid