Excellent Crawfordsville Crinoids Structure Study

Name: Inaudinata; Cladida; Cyathocrinites iowensis, Platycrinites saffordi

Age: Lower Mississippian Osagean Stage

Size (25.4 mm = 1 inch): Crinoid: Cyathocrinites Crown 45 mm long by 30 mm wide Platycrintes Stem: 98 mm long Matrix: 130 mm by 130 mm

Location: Crawfordsville, Indiana

Cyathocrinites iowensisDescription: A fine example of an advanced Inadunate Cladid crinoid of the Family Cyathocrinidae, this is Platycrinites saffordiCyathocrinites iowensis. The elegantly helical stem is diagnostic of the member of the Platycrinitidae known as Platycrinites saffordi. The stem of a crinoid served two main functions: placing the crown into the water column to filter out food particles, and anchoring the crinoid in the substrate. The fingerlike structures projecting from the stem are the radicular cirri which show this crinoid favored a muddy bottom. These crinoids must have been rapidly buried to be preserved in such a fine state of preservation. They are very esthetically displayed on this pentagonal siltstone matrix block.

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