Earliest crinoids: New evidence for the origin of the dominant Paleozoic echinoderms

Abstract

Research Article| February 01, 2001 Earliest crinoids: New evidence for the origin of the dominant Paleozoic echinoderms Thomas E. Guensburg; Thomas E. Guensburg 1Physical Science Division, Rock Valley College, Rockford, Illinois 61114, USA Search for other works by this author on: GSW Google Scholar James Sprinkle James Sprinkle 2Department of Geological Sciences, University of Texas, Austin, Texas 78712, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Thomas E. Guensburg 1Physical Science Division, Rock Valley College, Rockford, Illinois 61114, USA James Sprinkle 2Department of Geological Sciences, University of Texas, Austin, Texas 78712, USA Publisher: Geological Society of America Received: 27 Jul 2000 Revision Received: 30 Oct 2000 Accepted: 03 Nov 2000 First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (2001) 29 (2): 131–134. https://doi.org/10.1130/0091-7613(2001)029<0131:ECNEFT>2.0.CO;2 Article history Received: 27 Jul 2000 Revision Received: 30 Oct 2000 Accepted: 03 Nov 2000 First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Thomas E. Guensburg, James Sprinkle; Earliest crinoids: New evidence for the origin of the dominant Paleozoic echinoderms. Geology 2001;; 29 (2): 131–134. doi: https://doi.org/10.1130/0091-7613(2001)029<0131:ECNEFT>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract The oldest crinoids have been discovered in Early Ordovician strata of the western United States. A set of emergent crinoid traits based on these and other early crinoids enables reinterpretation of crinoid origins and early history. The new fossils retain primitive echinoderm characteristics, including ambulacral floor plates and largely unorganized cup plating, a first for crinoids. They lack shared derived characteristics linking them to other stalked echinoderms, including blastozoans. Contrary to current widespread opinion, crinoids originated as an independent group during the Cambrian, apparently from an edrioasteroid ancestor. All four major Paleozoic crinoid clades had evolved by the early Ibexian (Tremadocian), and this initial diversification slightly preceded those of most other Paleozoic evolutionary fauna components. These earliest crinoids attached to carbonate hardgrounds developed on sponge-algal mounds, intraformational conglomerates, and grainstones. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.