SOFT-TISSUE PRESERVATION OF THE HIND GUT IN A NEW GENUS OF CLADID CRINOID FROM THE MISSISSIPPIAN (VISEAN, ASBIAN) AT ST ANDREWS, SCOTLAND |
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Authors: | THOMAS W KAMMER WILLIAM I AUSICH† |
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Institution: | Department of Geology and Geography, West Virginia University, Morgantown, WV 26506-6300, USA;e-mail:; Department of Geological Sciences, 155 South Oval Mall, The Ohio State University, Columbus, OH 43210, USA;e-mail: |
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Abstract: | Abstract: Soft-tissue preservation of the hind gut, or anal sac, in the tegmen of Tubulusocrinus (gen. nov.) doliolus (Wright) from the Mississippian (Visean, Asbian) Pittenweem Formation at St Andrews, Scotland, is the first of its kind known in crinoids; it sheds important new light on the nature of the cladid tegmen. Many cladid crinoids had a calcite-plated anal sac that may have functioned like a chimney to prevent fouling of the ambulacra. The tubular, uncalcified anal sac of Tubulusocrinus may have functioned like a hose by pointing down current between the arms to avoid fouling of the ambulacra. Its smaller size may also have required less energy to produce than a heavy-plated sac. The hind gut is apparently preserved by haematite replacement, which was probably altered from original authigenic pyrite that formed soon after catastrophic burial. |
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Keywords: | Anal sac crinoids Mississippian Scotland tegmen soft tissues |
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